Patent Publication Number: US-2021177646-A1

Title: Intrauterine contraceptive device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/224,312, filed Dec. 18, 2018, entitled, “INTRAUTERINE CONTRACEPTIVE DEVICE,” which is a continuation of U.S. patent application Ser. No. 15/217,295 filed Jul. 22, 2016, entitled, “INTRAUTERINE CONTRACEPTIVE DEVICE,” now U.S. Pat. No. 10,159,596, which is a continuation of U.S. patent application Ser. No. 14/796,965, now U.S. Pat. No. 9,427,351, filed Jul. 10, 2015, entitled “INTRAUTERINE CONTRACEPTIVE DEVICE,” which is a continuation of U.S. patent application Ser. No. 13/795,940, now U.S. Pat. No. 9,089,418, filed Mar. 12, 2013, entitled “INTRAUTERINE CONTRACEPTIVE DEVICE,” which is a continuation-in-part of U.S. patent application Ser. No. 13/585,039, now U.S. Pat. No. 9,265,652, filed Aug. 14, 2012, entitled “INTRAUTERINE CONTRACEPTIVE DEVICE.” The disclosures of all the above-referenced patent applications are hereby incorporated by reference in their entireties herein. 
    
    
     FIELD 
     The invention relates generally to medical devices. More specifically, the invention relates to an intrauterine device for contraception and method for use. 
     BACKGROUND 
     Intrauterine devices (IUDs) are a commonly used form of contraception. There are two basic types of currently available IUDs—copper-releasing and progesterone-releasing. The copper IUD is a T-shaped device made of polyethylene wrapped with copper wire. The device acts as a foreign body within the uterus and releases copper to produce a chemical effect on the endometrium of the uterus and to alter the production of cervical mucus, thus producing a spermicidal environment. 
     Progesterone-releasing IUDs are also T-shaped devices and include a cylindrical reservoir containing levonorgestrel, which is released into the uterus over time. The levonorgestrel adds to the foreign body effects to create added spermicidal action and also thickens cervical mucus to act as a barrier to sperm penetration into the uterus. 
     Although both copper and progestin-releasing IUDs work well for contraception, both have common side effects. The most common side effects with copper IUDs are abnormal bleeding and pain. The most common side effects with levonorgestrel IUDs are hormone-related effects, such as headaches, nausea, breast tenderness, depression and cyst formation. When either copper or hormone/levonorgestrel is used as an active ingredient, it is typically thought that the larger the surface area of copper or hormone exposed in the uterus, the better the contraceptive action of the IUD. Although a larger surface area of exposed copper or hormone creates a higher risk of abnormal bleeding or other side effects, it is thought to be necessary to achieve effective birth control. Thus, for example, currently available copper IUDs typically have an exposed copper surface area of 380 mm squared. Past scientific studies of similarly configured IUDs, but with a reduced copper surface area of 200 mm squared, showed higher failure rates (undesirable pregnancies) in the range of 3%-10%. 
     In addition to the above shortcomings, many currently available IUDs are at least slightly uncomfortable and/or challenging to deliver into the uterus. All IUDs are delivered through the cervix using a delivery sheath. Although this delivery method works well in many cases, the required size of the currently available IUDs typically requires a sheath having an outer diameter that can cause pain or discomfort upon insertion into a cervix. In some cases, the pain can even be significant. Thus, the size of currently available IUDs and their delivery sheaths is another shortcoming. 
     Therefore, although existing IUDs work relatively well for their purpose of contraception, there is still a need for improved IUDs. Ideally, such improved IUDs would provide reliable, long-acting contraception with relatively few, minor side effects. At least some of these objectives are met by the embodiments described in this application. 
     BRIEF SUMMARY 
     Based on the various drawbacks of currently available IUDs, various embodiments of IUDs described herein provide contraception without the use of copper, levonorgestrel, other hormones or other substances. These IUDs provide contraception by providing an effective foreign body response within the uterus and in some cases by applying pressure against the uterine wall. The IUDs described herein are generally made at least in part of shape memory material, such as but not limited to Nitinol. 
     In other embodiments described herein, an IUD may deliver copper and/or another spermicide in a targeted fashion to one or more targeted areas within the uterus. For example, in one embodiment, copper may be focally delivered by at IUD at or near openings of the fallopian tubes and at or near the cervical os. By delivering a substance more selectively (or “focally”), these IUD embodiments provide effective contraception with smaller doses of copper (or other substance) than currently available IUDs. Generally, the limited, focal delivery of a substance such as copper is augmented by the IUD acting as a foreign body within the uterus, thus providing effective contraception. 
     In one aspect, a method for promoting contraception by placing a contraceptive device within a uterus without blocking fallopian tubes may include advancing a distal end of a delivery device through a cervix, advancing the contraceptive device comprising an elongate shape memory member out of the distal end of the delivery device and into the uterus, and limiting inferior migration of the contraceptive device within the uterus. Advancing the contraceptive device out of the distal end of the delivery device may cause the device to expand from a first, compressed shape within the delivery device to a second, expanded shape within the uterus. In the expanded shape, two tissue contact surfaces at opposite ends of the shape memory member may contact the inner wall of the uterus, and each of the tissue contact members, when the contraceptive device is delivered, may be positioned near, but not within, an opening of one of the two fallopian tubes branching from the uterus. Inferior migration may be limited by allowing the contraceptive device to assume a third shape, when subjected to pressure that tends to cause a downward migration of the device within the uterus, in which the tissue contact members are closer together than in the second shape and in which an expandable middle portion of the device is expanded to contact the inner wall of the uterus and thus limit the downward migration of the device. 
     In some embodiments, each of the tissue contact surfaces, when the device is delivered, may be positioned within approximately 2 cm of an opening of one of the fallopian tubes. Optionally, some embodiments of the method further involve delivering a substance within the uterus via the contraceptive device, where the substance may include but is not limited to one or more hormones, spermicides, copper and/or therapeutic agents. In one embodiment, delivering the substance may involve delivering copper to at least one selected area of the uterus in a more concentrated dose than to at least one other area of the uterus via at least one substance delivery member disposed on the contraceptive device in at least one location configured to provide the substance at the at least one selected area. In some of such embodiments, a total exposed surface area of the substance delivery member(s) may equal no more than about 200 square millimeters. In some embodiments, the substance delivery member(s) may include at least two substance delivery members, and each of the at least two substance delivery members may be positioned on the contraceptive device so that it will be located at or near an ostium of one of the fallopian tubes when the contraceptive device is delivered to the uterus. Optionally, the substance delivery member(s) may further include at least one additional substance delivery member positioned on the contraceptive device so that it will be located at or near an internal cervical os when the contraceptive device is delivered to the uterus. 
     In some embodiments, the method may further include removing the contraceptive device through the cervix by pulling on a thread connected to the contraceptive device. In some embodiments, the distal end of the delivery device may be tapered, and the contraceptive device may be completely contained within the delivery device during advancement of the delivery device through the cervix. In some embodiments, advancing the contraceptive device out of the delivery device may involve delivering the contraceptive device to a first, inferior location in the uterus, and the method may further include allowing the contraceptive device to migrate superiorly to a second location in the uterus after delivery. In some embodiments, the method may further involve applying sufficient pressure against the wall of the uterus with the tissue contact surfaces to promote contraception. 
     In another aspect, a method for promoting contraception may involve delivering a substance to one or more targeted areas in a uterus in a more concentrated dose than to at least one other area in the uterus via a contraceptive device having at least one substance delivery member located thereon. In such a method, a total exposed substance delivery surface area of the substance delivery member(s) may equal no more than about 200 square millimeters. 
     In some embodiments, the method may also involve, before delivering the substance, advancing a distal end of a delivery device through a cervix, and advancing the contraceptive device comprising an elongate shape memory member out of the distal end of the delivery device and into the uterus, thus causing the contraceptive device to expand from a first, compressed shape within the delivery device to a second, expanded shape within the uterus, where two tissue contact surfaces at opposite ends of the shape memory member contact the inner wall of the uterus when the contraceptive device is in the second shape, and where each of the tissue contact members, when the contraceptive device is delivered, is positioned near, but not within, an opening of one of the two fallopian tubes branching from the uterus. 
     In some embodiments, the substance is copper, and the substance delivery member(s) include at least a first substance delivery member positioned on the elongate member at or near a first one of the tissue contact surfaces, a second substance delivery member positioned on the elongate member at or near a second one of the tissue contact surfaces, and a third substance delivery member positioned on the elongate member at or near a middle portion configured to be located at or near a cervical os when the contraceptive device is located within the uterus. In some embodiments, the method may further include limiting inferior migration of the contraceptive device within the uterus by allowing the contraceptive device to assume a third shape when subjected to pressure that tends to cause a downward migration of the device within the uterus, in which the tissue contact members are closer together than in the second shape and in which an expandable middle portion of the device is expanded to contact the inner wall of the uterus and thus limit the downward migration of the device. In some embodiments, the method may further include applying sufficient pressure against the wall of the uterus with the tissue contact surfaces to promote contraception. 
     In some embodiments, the substance is copper, and the substance delivery member(s) include at least three substance delivery members, two of which are positioned on the contraceptive device so that they will be located at or near an ostium of a fallopian tube and one of which is positioned on the contraceptive device so that it will be located at or near a cervical os when the contraceptive device is delivered to the uterus. In alternative embodiments, the substance may be one of any number of spermicidal agents other than copper. In some embodiments, the method may further include delivering an additional substance to the uterus, where the additional substance may include but is not limited to Levonorgestrel, other hormones and/or therapeutic agents. In various embodiment, the total exposed surface area of the substance delivery members may equal no more than about 200 square millimeters. 
     In another aspect, a method for promoting contraception by focally delivering a substance within a uterus may first involve advancing a contraceptive device out of a distal end of a delivery device and into the uterus, thus causing the contraceptive device to expand from a first, compressed shape within the delivery device to a second, expanded shape within the uterus, where two tissue contact surfaces at opposite ends of the contraceptive device contact an inner wall of the uterus when the contraceptive device is in the second shape, and where each of the tissue contact surfaces, when the contraceptive device is delivered, is positioned near, but not within, one of two fallopian tube openings. Next, the method may involve delivering the substance to at least one targeted area of the uterus over time, via the contraceptive device, where the at least one targeted area includes areas at or near both of the fallopian tube openings, and where the contraceptive device includes at least one substance delivery member located at or near each of the tissue contact surfaces to deliver the substance at or near the fallopian tube openings. Finally, the method may also involve allowing the contraceptive device to partially collapse within the uterus such that the at least one substance delivery member forms a continuous line across the uterus from one side to an opposite side of the inner wall of the uterus. 
     In some embodiments, the contraceptive device may include at least three substance delivery members, and advancing the contraceptive device may cause at least one of the substance delivery members to be positioned at or near each of the openings of the fallopian tubes and one of the substance delivery members to be positioned at or near a cervical os. In some embodiments, delivering the substance comprises delivering copper, and a total exposed surface area of the substance delivery members is no more than about 200 square millimeters. In some embodiments, the contraceptive device may include an elongate shape memory member, the substance delivery member(s) may be formed as sleeves disposed around the shape memory member, and allowing the contraceptive device to partially collapse causes the substance delivery members to move together to form an approximately continuous cylinder. 
     In another aspect, a method for approximating contractility of a uterus may first involve advancing a contraceptive device comprising a shape memory member out of the distal end of a delivery device and into the uterus, thus causing the contraceptive device to expand from a first, compressed shape within the delivery device to a second, expanded shape within the uterus, where two tissue contact surfaces at opposite ends of the contraceptive device contact the inner wall of the uterus when the contraceptive device is in the second, expanded shape, and where each of the tissue contact surfaces, when the contraceptive device is delivered, is positioned near, but not within, an opening of a fallopian tube. The method may then involve visualizing, using a visualization device, the contraceptive device in the second shape in which a middle portion of the device is expanded. The method may then involve approximating contractility of the uterus by comparing an amount of expansion of the middle portion of the device with a known amount of expansion of the middle portion when the device is completely unconstrained. In some embodiments, visualizing the contraceptive device may involve using a radiographic visualization device positioned outside the uterus and at least a portion of the middle portion of the contraceptive device may be radiopaque. 
     In another aspect, a shape memory, intrauterine, contraceptive device may include two tissue contact surfaces at or near opposing ends of the device, an expandable middle portion between the tissue contact surfaces, and a spring portion at or near a midpoint of the elongate member. The contraceptive device may be configured to move from a first, default configuration when unconstrained to a second, partially collapsed configuration when the two tissue contact surfaces are forced toward one another by an inner wall of a uterus. The expandable middle portion is expanded in the second shape such that it contacts the inner wall of the uterus to help prevent migration of the contraceptive device out of the uterus. 
     In some embodiments, the two tissue contact surfaces, the middle portion and the spring portion comprise one shape memory wire. In some embodiments, the spring portion, the middle portion, and two arms extending from the middle portion comprise a shape memory wire, and the device further includes two tissue contact members, each of which is coupled with one of the opposing ends of the shape memory wire to form the tissue contact surfaces. In some embodiments, the contraceptive device may include a shape memory wire made of a material such as but not limited to Nitinol, other shape memory metal alloys and/or shape memory polymers. In one embodiment, the shape memory wire may have a diameter of between about 0.015 inch and about 0.017 inch. In one embodiment, the middle portion may be expandable, in the second shape, to a width approximately equal to a distance between the two tissue contact surfaces. In one embodiment, the device may be compressible into a third, fully collapsed configuration for positioning within a delivery sheath having an inner diameter of between about 2.70 mm and about 2.90 mm. 
     Some embodiments may further include a substance coupled with the device for delivery to the uterus, such as but not limited to one or more hormones, spermicides, copper, zinc and/or therapeutic agents. In some embodiments, the substance may be coupled with the device via at least one substance delivery member attached to the device. In some embodiments, the substance may be copper, and a total exposed surface area of the substance delivery member(s) is no more than approximately 200 square millimeters. In some embodiments, the contraceptive device may include a shape memory wire, and the substance delivery member(s) may include a first copper sleeve disposed over the shape memory wire at or near a first one of the tissue contact surfaces, a second copper sleeve disposed over the shape memory wire at or near a second one of the tissue contact surfaces, and a third copper sleeve disposed over the shape memory wire at or near the spring portion. 
     In some embodiments, a contraceptive device for focally delivering a substance in a uterus may include an elongate shape memory member having two opposing ends and a spring portion between the opposing ends and at least one substance delivery member disposed along a minority of a length of the shape memory member at a location to locally deliver the substance, when the contraceptive device is placed in the uterus, to at least one of an area near a fallopian tube or an area near a cervical os. 
     In some embodiments, the substance delivery member(s) may include two substance delivery sleeves, where each of the sleeves is disposed over the shape memory member at or near one of the opposing ends. In some embodiments, the substance delivery member(s) may include a substance delivery sleeve disposed over the shape memory member at or near the spring portion. In some embodiments, the substance delivery member(s) may include at least one substance delivery sleeve disposed over the shape memory member at or near each of the opposing ends and at least one substance delivery sleeve disposed over the shape memory member at or near the spring portion. In some embodiments, the substance may include copper or any of a number of other spermicidal agents. In one embodiment, the substance is copper, and the substance delivery members have a total surface area no more than about 200 square millimeters. Optionally, the device may further include a hormone delivery member disposed at a different location along the shape memory member from a location of the substance delivery member. 
     In another aspect, an intrauterine device for promoting contraception without blocking the fallopian tubes may include an elongate shape memory member having two opposing ends, a spring portion at approximately a midpoint between the two ends, a default configuration when released from constraint, and a collapsed configuration when constrained. The device may further include least one copper delivery member coupled with the shape memory member at or near each of the two ends for focally delivering a substance to a uterus in an area at or near openings of the fallopian tubes, where a total exposed surface area of the substance delivery members is no more than 200 square millimeters. 
     In some embodiments, the shape memory member may further include an expandable middle portion that expands when the two opposing ends are forced toward one another by an inner wall of the uterus, wherein the expanded middle portion may contact the wall of the uterus to help prevent migration of the device out of the uterus. In some embodiments, the substance delivery members, when pushed together by the inner wall of the uterus pushing together the opposing ends, form an approximately continuous line across the uterus. In some embodiments, the elongate member is made of a shape memory material, such as but not limited to Nitinol, other shape memory metal alloys and/or shape memory polymers. 
     In some embodiments, the two opposing ends may be looped portions of the elongate member, and the elongate member may be made of Nitinol. In some embodiments, the spring portion may be a spring having at least one coil formed in the elongate member. In some embodiments, the device in the collapsed configuration may be sufficiently small to fit within a delivery sheath having an inner diameter of between about 2.70 mm and about 2.90 mm. In some embodiments, the elongate member may have a diameter of between about 0.015 inch and about 0.017 inch. In some embodiments, the substance delivery member(s) may include multiple substance delivery sleeves disposed over the shape memory member. In some embodiments, the sleeves may include at least one sleeve at or near one of the ends, one sleeve at or near an opposite end, and one sleeve at or near the spring portion. 
     In another aspect, a contraceptive device that may also be used for approximating contractility of a uterus may include an elongate shape memory member having two opposing ends, a spring portion at a midpoint of the elongate member, a default expanded configuration, and a collapsed configuration. The device may also include two tissue contact surfaces, each of which is disposed at one of the opposing ends of the elongate member and a middle portion of the elongate member that expands in direct proportion to compression pressures acting upon the two tissue contact surfaces such that a separation distance of the middle portion of the elongate member may be used to approximate contractility of the uterus. Optionally, the device may also include at least one radiopaque marker or material on the middle portion of the elongate member to facilitate visualization of the middle portion using a radiographic visualization device. 
     In another aspect, a contraceptive system may include a shape memory, intrauterine, contraceptive device and a delivery device for housing and delivering the contraceptive device into the uterus through a cervix. The contraceptive device may include two tissue contact surfaces at or near opposing ends of the device and an expandable middle portion between the tissue contact surfaces. The contraceptive device may be configured to move from a first, default configuration when unconstrained to a second, partially collapsed configuration when the two tissue contact surfaces are forced toward one another by an inner wall of a uterus, where the expandable middle portion is expanded in the second shape such that it contacts the inner wall of the uterus to help prevent migration of the contraceptive device out of the uterus. The delivery device may include a shaft having a tapered distal tip and a pusher member disposed inside the shaft for at least one of advancing the contraceptive device out of the distal tip or maintaining a position of the contraceptive device within the shaft while the shaft is retracted. 
     In some embodiments, the contraceptive device may be preloaded into the shaft of the delivery device before providing the system to a customer. For example, in some embodiments, the contraceptive device may be preloaded through a proximal end of the shaft of the delivery device. In some embodiments, the shaft of the delivery device may have an inner diameter of no more than about 3.00 mm and an outer diameter of no more than about 3.40 mm. In some embodiments, the contraceptive device may include a Nitinol wire. In some embodiments, the shaft of the delivery device may include an inner surface having at least one slot for directing advancement of the contraceptive device out of the distal tip. Optionally, the contraceptive device may further include at least one substance delivery member for delivering a substance within the uterus. In some embodiments, the substance is copper, the substance delivery member(s) include at least one substance delivery member at or near each of the tissue contact surfaces, and a total exposed surface area of the substance delivery member(s) is no more than about 200 square millimeters. 
     In another aspect, A contraceptive device for focally delivery a substance in a uterus comprises an elongate shape memory member having two opposing ends located at each end of a pair of arms, a portion between the opposing ends comprising a portion of the pair of arms that cross each other in a series of twists, wherein the arms exit the series of twists to form the opposing ends, and at least one substance delivery member disposed along a portion of the elongate shape memory member at a location to locally deliver the substance, when the contraceptive device is placed in the uterus, to at least one of an area near a fallopian tube or an area near a cervical os, or both. The length, placement, or number of turns of the series of twists may at least in part define the device stiffness. 
     These and other aspects and embodiments of the invention are described in greater detail below, with reference to the drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of an intrauterine device (IUD), according to one embodiment; 
         FIGS. 2A-2F  show a cross-sectional view of a uterus, cervix and fallopian tubes, illustrating a method for delivering an intrauterine device (IUD) into a uterus, according to one embodiment; 
         FIG. 3  is a front view of an IUD, according to an alternative embodiment; 
         FIGS. 4A and 4B  illustrate a method for using the IUD of  FIG. 3 , according to one embodiment; 
         FIG. 5  is a front view of an IUD including copper sleeves for focal copper delivery, according to one embodiment; 
         FIGS. 6A and 6B  are front and perspective views, respectively, of an IUD including copper sleeves for focal copper delivery, according to an alternative embodiment; 
         FIGS. 7A and 7B  are cross-sectional views of a uterus, showing an insertion location and a migrated location of an IUD such as that shown in  FIGS. 6A and 6B , according to one embodiment; 
         FIGS. 8A and 8B  are cross-sectional views of a uterus, showing expanded and partially contracted views of an IUD including copper sleeves for focal copper delivery, according to one embodiment; 
         FIGS. 9A-9D  are front, bottom, side and perspective views, respectively, of an IUD including copper sleeves for focal copper delivery, according to another alternative embodiment; 
         FIG. 10  is a front view of an IUD including a twisted middle portion and copper sleeves for focal copper delivery, according to one embodiment; and 
         FIG. 11  is a perspective view of an IUD delivery device, according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , in one embodiment, a contraceptive intrauterine device (IUD)  1010  may include a shape memory, elongate member  1012  and two tissue contact members  1016 ,  1018  disposed at opposite ends of elongate member  1012 . Elongate member  1012  may include a spring portion  1014 , typically but not necessarily disposed approximately at a midpoint between the opposite ends of elongate member  1012 , an expandable middle portion  1020 , two arms  1015  extending from middle portion  1020 , and bends  1022  between middle portion  1020  and arms  1015 . All or a part of each tissue contact member  1016 ,  1018  may comprise a tissue contact surface, in other words, a surface that typically contacts an inner wall of a uterus when IUD  1010  is deployed in the uterus. 
     Elongate member  1012  is manufactured from a resilient, shape memory material, such as but not limited to Nitinol (nickel titanium alloy), spring stainless steel, other shape memory metal alloys, shape memory polymers, or the like, and has a default (or “predetermined”) expanded configuration as shown in  FIG. 1 . Elongate member  1012  may be compressed into a low profile, collapsed configuration, to facilitate preloading of IUD  1010  into a delivery sheath and delivery of IUD  1010  through a cervix via the sheath. When released from compression within the uterus, IUD  1010  springs back into its default expanded configuration to allow tissue contact members  1016 ,  1018  to contact the uterine wall and, by the force inherent in its shape memory material, apply sufficient pressure against the inner wall of the uterus to maintain IUD  1010  in position within the uterus. In many cases, IUD  1010  may not spring back into its fully expanded, default configuration when delivered into the uterus, due to force applied upon it by the uterine wall. Thus, it is possible to discuss an “expanded configuration” of IUD  1010  without necessarily meaning that it is fully expanded to it default configuration. 
     In some embodiments, IUD  1010  may be configured to assume a partially collapsed configuration, in which the uterine wall has pushed the two tissue contact members  1016 ,  1018  together to cause middle portion  1020  to expand laterally. This partially collapsed configuration is described in further detail below. Generally, this configuration may occur when forces applied by the uterine wall cause IUD  1010  to migrate slightly in an inferior direction (i.e., toward the cervical os). As middle portion  1020  expands, it may help prevent further inferior migration by contacting the inner uterine wall and thus acting as a stop mechanism. 
     In its fully expanded configuration, such as in  FIG. 1 , (or when partially expanded) IUD  1010  in some embodiments applies outwardly directed pressure against the uterine wall that is sufficient only to help maintain IUD  1010  in a desired location in the uterus and prevent or at least limit inferior migration. In these embodiments, IUD  1010  provides contraceptive effect primarily or exclusively by acting as a foreign body in the uterus. In alternative embodiments, IUD  1010  may apply a greater amount of pressure against the uterine wall, such that the applied pressure helps facilitate or enhance the contraceptive effect. Various embodiments of IUD  1010  described herein may thus be “pressure-applying” or “non-pressure-applying,” but in either case they will be configured to provide effective contraception. Thus, any particular embodiment described herein should not be interpreted to limit the claims to a particular amount of pressure applied to a uterus, unless such limitation is specifically set forth in a claim. 
     As illustrated in  FIG. 1 , in one embodiment, spring portion  1014  is disposed at the vertex (or bottom) of elongate member  1012 , middle portion  1020  extends upward from spring portion  1014  in approximately an elongate oval shape, elongate member  1012  crosses over itself and forms bends  1022 , and then it extends into arms  1015 . Although this configuration is described in reference to this embodiment, IUD  1010  may have any of a number of different expanded configurations in alternative embodiments. Furthermore, although the term “spring portion” is used to describe a portion of elongate member  1012  that helps confer laterally directed pressure to tissue contact members  1016 ,  1018 , spring portion  1014  is not necessarily a spring. In many of the embodiments, for example, spring portion  1014  is simply a midpoint of elongate member  1012  that is formed as a loop. In other embodiments, spring portion  1014  may have any of a number of different shapes. 
     IUD  1010  may be said to have a wingspan (or “width”) W, as measured from a tip of one tissue contact member  1016  to a tip of the other tissue contact member  1018 . IUD  1010  may also be said to have a height (or “length”) H, as measured from the bottom of spring portion  1014  to the tops of tissue contact members  1016 ,  1018 . Wingspan W and height H are generally selected to provide IUD  1010  with a desired amount of laterally directed pressure at tissue contact members  1016 ,  1018 , so that IUD  1010  will maintain itself in a given location within the uterus and exert sufficient pressure to promote contraception. In one embodiment, for example, IUD  1010  may have a height H of between about 25 mm and about 28 mm and a wingspan W of between about 44 mm and about 46 mm. Alternative sizes may be provided to enhance the effectiveness of IUD  1010  in different female anatomies, but because IUD  1010  is sufficiently resilient and the uterus is typically a closed space, IUD  1010  is generally a “one size fits all” device. 
     As just mentioned, the uterus (or “uterine cavity”) is generally not an open space. Even though the uterus is typically illustrated as an open space, such as in  FIGS. 2A-2F , this is simply a schematic illustration, because the uterus itself is a closed space. IUD  1010  should, therefore, have sufficient laterally directed pressure when released from a delivery device within the uterus to expand within the closed uterine cavity. The uterus is also typically a moist environment, so IUD  1010  should have sufficient resiliency to overcome any surface tension that might hold the opposed surfaces of the inner wall of the uterus together. In embodiments in which substances (copper, hormone, etc.) are not included, it is also important that IUD  1010  apply sufficient laterally directed pressure to promote contraception. It is believed that pressure applied to the inner uterine wall by tissue contact members  1016 ,  1018  may by itself disrupt the uterine environment in such a way to cause a spermicidal effect, thus preventing conception. The pressure exerted against the uterine wall by IUD  1010  may cause an inflammatory response, ischemia, compression of the spiral artery and/or a combination thereof, and any or all of these may help promote contraception. 
     Finally, IUD  1010  should have sufficient laterally directed pressure to prevent inferior migration of the device within the uterus or expulsion of the device from the uterus. As is described in greater detail below, IUD  1010  likely has the greatest contraceptive effect when it resides in a certain portion of the uterus, so ideally IUD  1010  will have sufficient outwardly directed pressure to prevent inferior migration or expulsion of the device. In some embodiments, IUD  1010  also has a configuration and applies sufficient force to promote superior migration of the device after delivery, which At the same time, another objective of IUD  1010  is to prevent perforation of the uterine wall, so IUD  1010  should not have an excessive amount of outwardly directed pressure. 
     IUD  1010  generates laterally directed, expansile pressure due to the nature of its resilient, shape memory material (typically but not necessarily Nitinol), the diameter of its material, and its default, expanded shape and size, including spring portion  1014 . Spring portion  1014  may in some embodiments be an actual spring or looped portion of elongate member  1012 , while in alternative embodiments it may be any of a number of other suitable shapes that help confer laterally directed pressure to elongate member  1012 . This laterally directed pressure pushes tissue contact members  1016 ,  1018  against the uterine wall with sufficient pressure that they first move along the wall to a desired location for promoting contraception and then maintain their position on (or “adhere to”) the wall at that location. IUD  1010  may also have a shape, size, lateral pressure, and size and shape of tissue contact members  1016 ,  1018  that help prevent tissue contact members  1016 ,  1018  from advancing (or “migrating”) into the fallopian tubes. It may be advantageous for IUD  1010  to avoid entering the fallopian tubes, because this may facilitate removal of IUD  1010  when desired. Delivery, adherence to the uterine wall and other characteristics of IUD  1010  are described in further detail below. By generating adhering pressure against the uterine wall, IUD  1010  remains in the uterus as a foreign body and provides further contraceptive effect by the application of pressure, thus safely preventing unwanted pregnancy. 
     As mentioned, in one embodiment, elongate member  1012  is made of Nitinol. In various embodiments, the diameter of elongate member  1012  may be selected to help provide a desired amount of lateral pressure generation when the device is in the default expanded configuration of  FIG. 1 . For example, in some embodiments, elongate member  1012  may be a Nitinol wire with a diameter of between about 0.010″ and about 0.025″ and more ideally between about 0.014″ and about 0.015″. 
     In alternative embodiments, resilient materials other than Nitinol may be used, such as other shape memory metal alloys, spring stainless steel or the like. Nitinol is typically preferred, however, due to its ability to remain in a compressed configuration (such as in a delivery catheter) for long periods of time, fully spring back into its expanded configuration, and maintain a constant but gentle pressure against the uterine wall for many years of useful life of IUD  1010 . The material properties of a Nitinol IUD  1010  allow it to be compressed into a collapsed or low profile configuration for storage in a delivery device, stored in that configuration for long periods of time, and then delivered out of the delivery device to assume its default, expanded configuration. Other resilient materials typically do not retain their full resilient properties over time in this way, although to the extent other materials would serve this purpose they may be used in alternative embodiments. Storing and/or packaging IUD  1010  within a delivery device makes its use easier, because the end user (typically a physician or physician&#39;s assistant) is not required to load the device into the delivery device. By contrast, currently available IUDs typically must be loaded into their delivery devices by a physician or physician&#39;s assistant before use. IUD  1010  formed of Nitinol is also unique in that it provides a constant lateral pressure in various uterine sizes and is thus a “one size fits all” device. Constant gentle lateral pressure along the inner uterine wall also prevents expulsion of IUD  1010  out of the uterus, which is one of the potential complications of currently available IUDs. 
     Tissue contact members  1016 ,  1018  may be comprised of any of a number of suitable materials and may have a number of different sizes and shapes. In some embodiments, IUD  1010  may include tissue contact members  1016 ,  1018  made of different or the same material as elongate member  1012 . Alternatively, an IUD may include “tissue contact surfaces” that are part of elongate member  1012 . These tissue contact surfaces may also be referred to as “tissue contact points” or “end points.” Tissue contact members  1016 ,  1018  also generally include tissue contact surfaces (i.e., a portion of each tissue contact member  1016 ,  1018  that contacts the uterine wall). Thus, the phrases “tissue contact members,” “tissue contact surfaces,” “tissue contact points” and “end points” may sometimes be used herein interchangeably and should not be interpreted to limit the scope of the invention as set forth in the claims. 
     Generally, the material, size and shape of tissue contact members  1016 ,  1018  are selected to prevent, or at least reduce the tendency for, tissue in-growth of tissue contact members  1016 ,  1018  into uterine wall tissue while also preventing inferior migration or expulsion of IUD  1010 . Tissue in-growth prevention is important for facilitating later removal of IUD  1010  from the uterus if and when desired. This prevention of tissue in-growth is in direct contrast to a number of prior art permanent contraception or sterilization devices that purposely try to promote tissue in-growth, for example to permanently attach a device within the fallopian tubes. IUD  1010 , in contrast, is usually easily removed and does not permanently adhere to the uterine wall. In one embodiment, tissue contact members  1016 ,  1018  may be made of a high density polyethylene. In alternative embodiments, tissue contact members  1016 ,  1018  may be made of any of a number of alternative, typically non-porous materials, such as but not limited to metals, plastics, elastomers such as silicone, or combinations thereof. Furthermore, tissue contact members  1016 ,  1018  may be coated, such as with a coating to prevent tissue in-growth, or may be impregnated with various medications or other substances, such as but not limited to hormone, spermicide or the like. Tissue contact members  1016 ,  1018  may also be made of (or coated with) an echogenic material to facilitate visualization of IUD  1010  using transvaginal ultrasound or other visualization techniques. 
     Tissue contact members  1016 ,  1018  may have any suitable size and shape but are generally configured to apply a desired amount of pressure to the uterine wall to maintain the position of IUD  1010 , in some embodiments to promote contraception, and to prevent tissue in-growth, without causing pain or uterine wall perforation, a well known risk of currently available intrauterine devices. Tissue contact members  1016 ,  1018  must also be sized so that they can be effectively delivered through a low profile delivery device without pain to the patient. To achieve these goals, tissue contact members  1016 ,  1018  according to one embodiment have a diameter of between about 1 mm and about 8 mm, and preferably between about 2 mm and about 4 mm, and even more preferably between about 2.5 mm and about 3.5 mm. Tissue contact members  1016 ,  1018  according to this embodiment may have a length of between about 3.0 mm and about 5.0 mm, and preferably between about 3.5 mm and about 3.6 mm. Also according to one embodiment, each tissue contact member  1016 ,  1018  has a surface area of between about 30 mm squared and about 45 mm squared, and preferably between about 31 mm squared and about 32 mm squared. Providing tissue contact members  1016 ,  1018  with a relatively large surface area (while keeping them small enough to fit within a delivery device) may help prevent uterine wall perforation and in-growth, while still allowing for the application of a desired amount of laterally directed pressure against the uterine wall. 
     Referring now to  FIGS. 2A-2F , a portion of the female reproductive anatomy is shown in schematic form in cross-section, and a method for delivering IUD  1010  to a uterus U is illustrated. As shown in  FIG. 2A , the vagina V leads into the cervix C, which in turn leads into the uterus U (illustrated schematically as an open cavity). The uterus U has an inner wall W, which in this application is referred to simply as the uterine wall. Two fallopian tubes F branch off of the uterus U. During the natural reproductive cycle, eggs travel down the fallopian tubes F to be fertilized by sperm (typically within a fallopian tube F), and the fertilized egg then implants on the uterine wall W to grow into a fetus. IUD  1010  works primarily or exclusively by producing a “hostile environment” in the uterus U for sperm and thus preventing fertilization, or secondarily, if fertilization occurs, by blocking implantation. 
     With reference to  FIG. 2B , as a first step in a method for IUD delivery, an IUD delivery device  1020  containing IUD  1010  (not visible in  FIG. 2B ) may be advanced through the cervix C into the uterus U. While housed in delivery device  1020 , IUD  1010  is in a collapsed, low profile configuration to facilitate its passage through the cervix C. In some embodiments, such as the one pictured, IUD  1010  may be completely contained within delivery device  1020  during advancement of delivery device  1020  through the cervix C. As will be described further below, IUD  1010  may be preloaded into a proximal end of delivery device  1020 , due to its shape memory material. This proximal preloading allows delivery device  1020  to have a tapered distal tip  1021 , which facilitates advancement of delivery device  1020  through the cervix C with little or no pain or discomfort. Proximal preloading of IUD  1010  into delivery device  1020  also makes the process easier for a user, since currently available IUDs must be pulled into the distal end of a delivery device by the physician or physician&#39;s assistant prior to use. Delivery device  1020  may take any of a number of suitable forms, typically including an outer sheath and an inner pusher member. One embodiment of a delivery device is described is described in further detail below with reference to  FIG. 10 . 
       FIGS. 2C and 2D  show the next steps in an IUD delivery process, according to one embodiment.  FIG. 2C  illustrates IUD  1010  partially expelled from delivery device  1020  into the uterus U. In  FIG. 2D , IUD  1010  has been completely expelled from delivery device  1020  but is still in contact with a pusher member  1022  of delivery device  1020 . At this point, tissue contact members  1016 ,  1018  are contacting the uterine wall W. In various embodiments, IUD  1010  may be expelled from delivery device  1020  using any of a number of different techniques and mechanisms. In one embodiment, for example, pusher member  1022  may be held in a stable position, and a sheath on delivery device  1020  may be retracted to expose IUD  1010 . Alternatively, a sheath may be held in a stable position and pusher member  1022  may be advanced to push IUD  1010  out of the distal end of delivery device  1020 . In another embodiment, pusher member  1022  may be advanced while a sheath is retracted. In other alternative embodiments, other suitable means for expelling IUD  1010  from delivery device  1020  may be used. 
     Comparing the position of IUD  1010  in  FIGS. 2C and 2D  shows that IUD  1010  may advance along the uterine wall W toward the fallopian tubes F during and/or after delivery to eventually seat (or “adhere”) in an area just below (or “inferior to”) the fallopian tube openings. Alternatively, IUD  1010  may simply be delivered directly to the desired location within the uterus U rather than delivering it to an initial location and having it ride along the uterine wall W before seating at its final location. The words “seat” and “adhere” do not mean that IUD  1010  permanently attaches to the uterine wall. In fact, as previously mentioned, tissue contact members  1016 ,  1018  and IUD  1010  are designed to prevent tissue in-growth and permanent attachment to the uterine wall. “Seating” and “adhering” are thus generally used to simply mean maintaining a relative position along the uterine wall. Ideally, but not necessarily, each tissue contact member  1016 ,  1018  will seat in an area of the uterine wall W within approximately 2 cm inferior of a fallopian tube opening, and preferably within approximately 1 cm inferior of a fallopian tube opening. This is believed to be an ideal area for IUD  1010  to reside for contraception, although an exact location for IUD  1010  within the uterus is not required. 
     Movement of IUD  1010  along the uterine wall and adherence of IUD  1010  at a given location are caused by a combination of the amount of outward pressure produced inherently by IUD  1010 , the size and shape of IUD  1010 , the size, shape and physical characteristics of tissue contact members  1016 ,  1018 , and the size and shape of the uterus U. IUD  1010  is configured to have enough outwardly directed pressure and other characteristics to make IUD  1010  adhere to the uterine wall W, typically near the fallopian tube orifices, without actually entering the fallopian tubes F. The pressure applied to the uterine wall W by the IUD  1010  is believed to be at least one reason that IUD  1010  prevents pregnancy. The constant, gentle pressure applied to the uterine wall W is believed to disrupt the natural uterine environment. In alternative embodiments, described further below, an IUD may simply contact the uterine wall and not apply any significant amount of pressure to the wall. In these embodiments, in other words, the IUD contacts the uterine wall with sufficient force only to maintain positioning of the IUD, in which case the IUD will include some form of substance delivery mechanism (copper, hormone, etc.) to provide contraceptive effect. 
     In its fully expanded, default configuration, IUD  1010  may have a wingspan or width W (described previously), of between about 18 mm and about 54 mm, depending upon the anatomical characteristics of the patient. The wingspan W of IUD  1010  may be selected at least in part due to the distance between the uterine wall W just inferior to one fallopian tube F and the uterine wall W just inferior to the opposite fallopian tube F. For example, the average intra-ostial distance in nulliparous women is 29.2 mm, and the average intra-ostial distance in parous women is 30.0 mm, so the IUD wingspan may in some embodiments be based at least in part on these measurements. (“Assessment Of The Uterine Cavity And The Intraostial Distance Using Hysterosalpingography”, Fertility and Sterility, Volume 88, Supplement 1, September 2007, Page 5202, J. G. Bromer, F. Sanguinetti, M. Tal, P. Patrizio. Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Conn.; Department of Radiology, Yale University School of Medicine, New Haven, Conn.) 
     As described previously, when expanded, one embodiment of IUD  1010  applies laterally directed pressure against the uterine wall W via tissue contact members  1016 ,  1018  to cause irritation/inflammation, ischemia, compression of arterial structures, and/or other effects that promote contraception. Additionally, IUD  1010  may apply sufficient pressure to slightly distort the shape of the uterine wall W, which is believed to further promote contraception. The amount of laterally directed pressure applied to the uterine wall W is important for proper functioning of IUD  1010 , both for adherence (and thus migration and expulsion prevention), and also for the added effect of uterine wall distortion. In various embodiments, a range of the pressure applied by tissue contact members  1016 ,  1018  to the uterine wall is between about 0.002 pounds-pressure and about 0.025 pounds-pressure, and ideally between about 0.002 pounds-pressure and about 0.015 pounds-pressure. 
     Referring to  FIG. 2E , IUD  1010  is shown in place in the uterus U, completely disconnected from delivery device  1020 . At this point, delivery device  1020  may be removed through the cervix C, leaving IUD  1010  in place, as shown in  FIG. 2F . IUD  1010  then remains in the uterus U for as long as desired to promote contraception. 
     IUD  1010  may be left in the uterus U permanently or may be removed at any time. Because IUD  1010  is easily delivered and removed, it allows for nonsurgical contraception as an office procedure and without the need for surgery or the necessity for visualization either radiologically, ultrasonically, or with a hysteroscope. IUD  1010  uses radial pressure and inherent properties in its construction to promote contraception, thus eliminating the need for hormones or copper in the device. IUD  1010  also uses radial pressure prevent inferior migration or expulsion. As such, IUD  1010  may be used for permanent or temporary contraception. As described further below, although IUD  1010  does not require the use of hormones, copper or other substances, in alternative embodiments it may also be adapted for local delivery of these or other therapeutic agents. In other alternative embodiments, IUD  1020  may be configured to provide contraceptive effect primarily or exclusively via delivery of a substance (copper, hormone, etc.) and not via application of pressure. IUD  1010  may also be used, in some embodiments, for treatment of one or more conditions such as abnormal uterine bleeding and/or pelvic pain, in addition to providing contraception. 
     Referring now to  FIG. 3 , in another embodiment, a contraceptive device (or “IUD”)  2100  may have a similar configuration to that described above, but may have an elongate shape memory member  2102  formed into loops at opposite ends to provide tissue contact surfaces (or “end points”)  2108   a ,  2108   b , rather than having tissue contact members attached to elongate member  2102 . In all other aspects, the embodiment of IUD  2100  in  FIG. 3  is the same as the embodiment of IUD  1010  in  FIG. 1 . As with the previously described embodiment, contraceptive device  2100  may include elongate member  2102 , an expandable middle portion  2104 , a spring portion  2106 , two bends  2110  and two arms  2112 . In various embodiments, elongate member  2102  may have a predominantly flat (or “two-dimensional”) configuration, as shown. Alternatively, elongate member  2102  may have a more three-dimensional configuration (not shown). For example, one or more portions of elongate member  2102  may be curved or bent, which in some embodiments may help elongate member  2102  conform to a curved shape of a uterus. 
     Contraceptive device  2100  is shown, in  FIG. 3 , in its fully expanded, unconstrained, default configuration. Contraceptive device  2100  may also be compressed into a long, thin configuration for placement within a delivery device (not shown), such as a delivery catheter or sheath, by pulling/pushing tissue contact surfaces  2108   a ,  2108   b  upward, away from spring portion  2106 . The delivery device may be sufficiently small so that it can be passed through a cervix without causing pain or discomfort and without requiring mechanical dilation, anesthesia (topical, local or general) or expansion of the cervix, cervical canal or internal or external cervical os. In some embodiments, for example, contraceptive device  2100  may be compressible/collapsible to a diameter that fits within a delivery sheath having an inner diameter of between about 2.50 mm and about 3.00 mm and more preferably between about 2.70 mm and about 2.90 mm, and an outer diameter of between about 2.80 mm and about 3.40 mm and more preferably between about 2.95 mm and about 3.20 mm. 
     When contraceptive device  2100  is released from its delivery catheter into the uterus, it expands to a configuration approximately like the configuration shown in  FIG. 3 . Typically, tissue contact surfaces  2108   a ,  2108   b  will help device  2100  adhere to uterine wall tissue to remain in place near but not in the fallopian tubes. However, if contraceptive device  2100  begins to migrate down (or out of) the uterus, the uterine wall will pressure tissue contact members  2108   a ,  2108   b  together, thus pushing out the sides of middle portion  2104 . The expanded sides of middle portion  2104  will then provide increased mechanical resistance, including but not limited to, contacting the uterine wall and helping to prevent or resist migration. The expansion of middle portion  2104  is directly proportional to the amount of compression placed on tissue contact surfaces  2108   a  and  2108   b  by the uterine wall, and thus the relative amount of contractility of the uterine wall. Thus, in some embodiments, the separation distance of middle portion  2104  (and/of tissue contact surfaces  2108   a ,  2108   b ) may be used as a measurement of uterine contractility. This is described further with reference to  FIGS. 4A and 4B . 
     Elongate member  2102  may be made of any suitable shape memory material, such as but not limited to Nitinol, other shape memory metal alloys or shape memory polymers. Tissue contact surfaces  2108   a ,  2108   b  may be made of the same material or a different material as elongate member  2102 . Typically, tissue contact surfaces  2108   a ,  2108   b  will be made of a material that resists slipping on the intrauterine wall but that also resists tissue ingrowth, as described previously. In some embodiments, tissue contact surfaces  2108   a ,  2108   b  may comprise balls of formed material, such as a polymer, deposited on the ends of elongate member  2102 . In other embodiments, such as the one in  FIG. 3 , tissue contact surfaces  2108   a ,  2108   b  are simply portions of elongate member  2102 . Generally, the term “end points” or “tissue contact members” or “tissue contact surfaces” or other similar terms are used herein to refer to portions of an IUD that contact the uterine wall when the IUD is in place. In many embodiments, the “tissue contact members” are at the ends of an elongate member and are the primary contact points of the IUD with the uterus. In some embodiments, however, such as the embodiment just described, IUD  2100  may include additional tissue contact surfaces or portions (for example expandable middle portion  2104 ), as will be described further below. Whether the term used in relation to a particular embodiment is “end points” or “tissue contact members” or “tissue contact surfaces” or some other similar term should not be interpreted to limit the scope of the invention as it is defined by the claims. 
     Forming tissue contact surfaces  2108   a ,  2108   b  as loops of elongate member  2102 , as in the embodiment shown in  FIG. 3 , may be advantageous for a number of reasons. One reason is that such a configuration will allow IUD  2100  to be collapsed down to a very small cross-sectional diameter for insertion into a delivery device, because the loops of elongate member  2102  can easily overlap. In some embodiments, for example, contraceptive device  2100  may be compressible/collapsible to a diameter that fits within a delivery sheath having an inner diameter of between about 2.50 mm and about 3.00 mm and more preferably between about 2.70 mm and about 2.90 mm, and an outer diameter of between about 2.80 mm and about 3.40 mm and more preferably between about 2.95 mm and about 3.20 mm. 
     Referring now to  FIGS. 4A and 4B , contraceptive device  2100  is shown immediately after being delivered into a uterus ( FIG. 4A ) and after slight migration down the uterine wall ( FIG. 4B ). In  FIG. 4A , device  2100  has been delivered, and tissue contact surfaces  2108   a ,  2108   b  are contacting the inner uterine wall U near but not within the fallopian tubes. In this position, tissue contact surfaces  2108   a ,  2108   b  apply pressure to the uterine wall U and are in an optimal position to prevent conception. In most cases, IUD  2100  will remain in this position or very close to it, due to the slip resistant nature of tissue contact surfaces  2108   a ,  2108   b . In many cases, in fact, IUD  2100  may be delivered inferiorly and migrate superiorly, sometimes contacting the fundus of the uterus U, as will be described in further detail below. In some cases, however, and with reference now to  FIG. 4B , contraceptive device  2100  may be subject to contractile pressures of the uterus which may cause the device to slide (or “migrate”) down the uterine wall U while remaining within the uterine cavity. Significant migration of any intrauterine device or ultimate expulsion of the device out of the uterus is obviously not desirable. Therefore, device  2100  is configured such that when end points  2108   a ,  2108   b  are forced closer together, middle portion  2104  expands or bows outward to contact the uterine wall U along secondary contact surfaces  2112 . Secondary contact surfaces  2112  are simply lengths of middle portion  2104  that may contact the uterine wall upon expansion of middle portion  2104 . Secondary contact surfaces  2112  and end points  2108   a ,  2108   b  thus act together to contact the uterine wall U and prevent inferior migration (or further inferior migration) of contraceptive device  2100 . In this way, contraceptive device  2100  is configured to prevent its own inferior migration and/or expulsion out of the uterus. 
     Additionally, the amount of separation distance of secondary contact surfaces  2112  of middle portion  2104  is directly proportional to the amount of compression of end points  2108   a  and  2108   b , and thus proportional to a relative amount of uterine wall contractility. This separation or expansion of middle portion  2104  may thus be used as a measurement tool for measuring approximate contractility of a uterus. In one embodiment, middle portion  2104  (or part of middle portion  2104 ) may be marked with one or more radiopaque markers or may be made radiopaque, to enhance visualization and thus facilitate measurement of uterine contractility. In other embodiments, end points  2108   a ,  2108   b  may have enhanced radiopacity for the same purpose. In still other embodiments, both middle portion  2104  and end points  2008   a ,  2008   b  may be made radiopaque or include radiopaque markers. A method may include visualizing the separation of middle portion  2104  and approximating an amount of uterine contractility from the separation. 
     The IUD embodiments described above provide effective contraception without the use of copper, Levonogestrel, other hormones or other drugs or substances. This may be advantageous in many circumstances, because any side effects potentially caused by such substances will be avoided by using a “substance-free” IUD. In some embodiments, however, it may be equally or even more advantageous to provide an IUD that delivers copper, hormone and/or one or more other substances in a limited dose to the uterus. For example, a focal substance delivery IUD according to one embodiment may deliver copper to a targeted area at or near each of the openings of the fallopian tubes and/or at or near a cervical os. Although some amount of copper will typically permeate most or all of the rest of the interior of the uterus, it may remain concentrated in the targeted areas of focal delivery. Thus, a lower dose of substance may be delivered while still providing effective contraception, since the delivery is targeted toward areas of enhanced contraceptive efficacy. In this way, a focal substance delivery IUD may provide contraception that is equal to or better than currently available devices while reducing or eliminating the side effects typically caused by such devices. 
     The IUD embodiments described below employ shape memory material to maintain contact with a uterine wall and also provide selective delivery of copper to targeted areas within the uterus. In alternative embodiments, any of the IUDs described above may be altered to include delivery of copper and/or one or more alternative substances. In some embodiments, an IUD may provide selective or targeted delivery of copper and application of uterine wall pressure to provide contraception. The delivery of lower dose copper or other substances described below may be generally referred to as “selective,” “targeted,” “focal,” “localized” or the like. These terms generally mean that a substance is purposely delivered to one or more areas within the uterus in a greater concentration than it is delivered to other parts of the uterus. In summary, the IUDs described herein may provide contraception by the application of pressure, by targeted delivery of copper or other substance, or by both. Therefore, although a number of IUD embodiments are described herein as having a particular mechanism of contraceptive action, in alternative embodiments they may be modified to have additional or other mechanisms also described herein. 
     Referring now to  FIG. 5 , in another embodiment, a contraceptive device (or “IUD”)  2200  similar to the one shown in  FIG. 3  may include an elongate shape memory member  2202  having two tissue contact surfaces (or “end points”)  2208   a ,  2208   b . Elongate member  2202  may have a two-dimensional (i.e., predominantly flat) configuration, as shown, or alternatively may have a more three dimensional (i.e., slightly bent out of plane) configuration, as discussed above. Elongate member  2202  may include a middle portion  2204 , a spring portion  2206 , and bends  2210  between the middle portion  2204  and the tissue contact surfaces  2208   a ,  2208   b . Spring portion  2206  is generally located at an approximate midpoint of the length of elongate member  2202 —i.e., at the bottom of IUD  2200 . Middle portion  2204  is capable of expanding to contact the uterine wall and limit inferior migration and expulsion, as described previously. 
     In this embodiment, four focal substance delivery members in the form of copper sleeves  2212  are disposed over elongate member  2202  close to tissue contact surfaces  2208   a ,  2208   b . Copper sleeves  2212  may deliver a small amount of copper to the uterine wall near one of the ideal locations for contraceptive effect—i.e., near and just below the fallopian tubes. By providing focal delivery of copper, contraceptive device  2200  may provide the beneficial contraceptive effect of copper without the side effects often seen with currently available copper IUDs—i.e., excessive and/or non-menstrual bleeding. Such focal delivery may also be described as “concentrated,” “selective,” “localized,” “targeted” or the like, as mentioned above. Copper sleeves  2212  generally cover only a minority of elongate member  2202 , and focal delivery of copper thus achieves the desired contraceptive effect while delivering a lower overall dose of copper to the uterus, compared with currently available IUDs. For example, copper sleeves  2212  of contraceptive device  2200  may have an exposed surface area of no more than about 200 square millimeters, and more ideally no more than about 150 square millimeters, and even more ideally no more than about 125 square millimeters. In the embodiment shown in  FIG. 5 , for example, the copper sleeves  2212  have a surface area of about 125 square millimeters. By comparison, currently available IUDs typically have copper measurements of about 380 square millimeters—i.e., over three times as much as the surface area of copper sleeves  2212 . By delivering copper locally, near an ideal location within the uterus, contraceptive device  2200  may accomplish the objective of copper without as many bleeding side effects. 
     In an alternative embodiment, copper may also be attached to contraceptive device  2200  at or near spring portion  2206 . Such copper may be attached, for example, in the form of one or more sleeves or one or more wires wrapped around elongate member  2202 . Copper located in this area on contraceptive device  2200  may be advantageous, because when contraceptive device  2200  is implanted, that portion of the copper will be located near to the cervical os (the opening of the cervix into the uterus). Copper disposed in this area will help stop sperm from proceeding farther into the uterus. In another alternative embodiment (not shown), copper may be included at or near spring portion  2206  and not near end points  2208   a ,  2208   b . In alternative embodiments, sleeves  2212  may be replaced by any other suitable substance delivery device(s), such as but not limited to copper wire(s), drug delivery depot(s), drug coatings, drug eluting carriers, or the like. 
     In yet other alternative embodiments (also not shown), copper sleeves  2212  may be used along with one or more hormone delivery devices, which may contain or be coated or impregnated with Levonorgestrel or any other suitable hormone, which may be released over time into the uterus. When a combination of copper and hormone is used, it may be possible to lower the doses of both the copper and the hormone to very low levels while still providing the desired contraceptive effect. In various embodiments, any suitable hormone delivery device (or devices) may be attached to elongate member  2202 , as desired. 
     Referring now to  FIGS. 6A and 6B , another alternative embodiment of a focal substance delivery contraceptive device (or “IUD”)  2300  is shown, in front and perspective views, respectively. In this embodiment, IUD  2300  may again include an elongate shape memory member  2302  having two tissue contact surfaces (or “end points”)  2308   a ,  2308   b . Elongate member  2302  may have a two-dimensional (i.e., predominantly flat) configuration, as shown, or alternatively may have a more three dimensional (i.e., slightly bent out of plane) configuration. Elongate member  2302  may include a middle portion  2304 , a spring portion  2306 , and bends  2310  between middle portion  2304  and tissue contact surfaces  2308   a ,  2308   b . Again, spring portion  2306  is generally located at an approximate midpoint of the length of elongate member  2302 —i.e., at the bottom of IUD  2300 . Attached to spring portion  2306  is a retrieval string  2305 , which may be a suture material or the like for retrieving the device  2300  from the uterus. 
     This embodiment includes copper sleeves  2312  near each of tissue contact surfaces  2308   a ,  2308   b  and additional copper sleeves  2314  near spring portion  2306 . Thus, the IUD  2300  may provide focal delivery of copper to areas of the uterus at or near openings of the fallopian tubes as well as at or near the cervical os. In one embodiment, the total surface area of copper sleeves  2312 ,  2314  may be no more than about 200 square millimeters and even more ideally no more than about 150 square millimeters. This embodiment includes four substance delivery sleeves  2312  near tissue contact surfaces  2308   a ,  2308   b  and two sleeves  2314  near spring portion  2306 . In alternative embodiments, any other suitable number of sleeves may be included, such as between 1 and 20 sleeves. In other alternative embodiments, sleeves  2312 ,  2314  may be replaced with some other form of substance delivery device or mechanism, such as but not limited to wires, coatings, apertures in elongate member  2302  that leak a substance, permeable materials, beads coated or impregnated with a substance, or the like. Additionally, in various embodiments, sleeves  2312 ,  2314  may be either loosely or tightly affixed to elongate member  2302 , so that they may be free to move in some embodiments and may be fixedly attached in others. 
     With reference now to  FIGS. 7A and 7B , as described previously, the various embodiments of the IUD described herein are configured to resist and/or limit inferior migration and expulsion of the IUD from a uterus. Some or all of the embodiments may also have a tendency, due to their configuration and shape memory material, to migrate superiorly within a uterus (i.e., toward the top or “fundus” of the uterus). For example, as shown in  FIG. 7A , the IUD  2300  may be delivered into a uterus U in a relatively inferior location (for example, just beyond the cervical os O). In this location, the device  2300  and its substance delivery members may be located relatively far from the openings of the fallopian tubes F. As shown in  FIG. 7B , however, the device  2300  may tend to expand and move superiorly up the uterus U to a position closer to the fallopian tube F openings. This second, migrated position may be more effective for contraception. However, in either location, the copper sleeves  2312 ,  2314  are located near the openings of the fallopian tubes F and the cervical os O, thus providing focal substance delivery in those areas. Thus, the embodiments described herein may facilitate delivery of an IUD, because it is possible to simply place the device just within the uterus and allow it to migrate to a more desirable location within the uterus. This will likely be easier than trying to position a device in an ideal location during initial delivery, which may require visualization, increased manipulation and potentially discomfort to the patient. 
     With reference now to  FIGS. 8A and 8B , in some embodiments, IUD  2300  may be delivered to (or may migrate to) a first, relatively superior location in the uterus, as shown in  FIG. 8A . At this location IUD  2300  may assume is fully expanded (or nearly fully expanded) configuration. At some later point, IUD  2300  may migrate slightly inferiorly, as shown in  FIG. 8B , thus causing copper sleeves  2312  (or other substance delivery devices) to move together to form a continuous line approximately horizontally across the uterus U. This approximately horizontal line of copper sleeves  2312  may act as an approximately horizontal, linear blockade to help block sperm from traveling through the uterus U toward the fallopian tubes F. At the same time, the other copper sleeves  2314  are still located at or near the cervical os O to further enhance contraception. 
     Referring now to  FIGS. 9A-9D , another alternative embodiment of a focal substance delivery contraceptive device (or “IUD”)  2500  is shown, in front, bottom, side and perspective views, respectively. In this embodiment, IUD  2500  has all the features of the embodiment of  FIGS. 6A and 6B , but also includes additional copper sleeves. Thus, IUD  2500  includes elongate shape memory member  2502  having two tissue contact surfaces (or “end points”)  2508   a ,  2508   b . Elongate member  2502  includes a middle portion  2504 , a spring portion  2506 , and bends between middle portion  2504  and tissue contact surfaces  2508   a ,  2508   b . Again, spring portion  2506  is generally located at an approximate midpoint of the length of elongate member  2502 —i.e., at the bottom of IUD  2500 . Attached to spring portion  2506  is a retrieval string  2505 , which may be a suture material or the like for retrieving the device  2500  from the uterus. 
     In the embodiment shown, IUD  2500  includes copper sleeves  2512  near each of the tissue contact surfaces  2508   a ,  2508   b  and additional copper sleeves  2514  near spring portion  2506 , as in  FIGS. 6A and 6B . In this embodiment, however, there are four additional copper sleeves  2514  near spring portion  2506 , rather than two. Additionally, there are two added copper sleeves  2513 , positioned on the loop formed at the opposite ends of elongate member  2502 . Thus, the IUD  2500  may provide focal delivery of copper to areas of the uterus at or near openings of the fallopian tubes as well as at or near the cervical os via a total of ten copper sleeves  2512 ,  2513 ,  2514 . In one embodiment, the total exposed surface area of the copper sleeves  2512 ,  2513 ,  2514  may be no more than about 200 square millimeters and even more ideally no more than about 150 square millimeters. 
     With reference now to  FIG. 10 , another alternative embodiment of a focal substance delivery contraceptive device (or “IUD”)  2600  similar to the one shown in  FIGS. 6A and 6B , and also including some of the extra copper sleeves of  FIGS. 9A-9D  is illustrated. This embodiment may include an elongate shape memory member  2602  having two tissue contact surfaces (or “end points”)  2608   a ,  2608   b . Elongate member  2602  may have a two-dimensional (i.e., predominantly flat) configuration, as shown, or may have a more three dimensional (i.e., slightly bent out of plane) configuration. Elongate member  2602  may include a middle portion  2604 , a loop portion  2606  disposed at the vertex (or bottom) of elongate member  2602 , and bends  2610  between middle portion  2604  and tissue contact surfaces  2608   a ,  2608   b . Attached to loop portion  2606  is a retrieval string  2605 , which may be a suture material or the like for retrieving the device  2600  from the uterus. The device  2600  includes copper sleeves  2612  near each of the tissue contact surfaces  2608   a ,  2608   b  and additional copper sleeves  2614  near loop portion  2606 , as described with respect to the device  2300  depicted in  FIGS. 6A and 6B . 
     In this embodiment, the bottom loop portion does not form any turns of a spring structure. Instead, to generate the resilience in the arms of the device as in the other embodiments described herein, this embodiment includes twists  2616  along the middle portion  2604  of the arms as they extend from the tissue contact surfaces toward the loop portion  2606 . Twists may be formed when the two arms of the elongate member  2602  cross each other more than once in a longitudinally extending helix containing multiple turns that run in series from closer to the loop portion  2606  outward along the arms until the arms diverge again from the twisted portion to form the opposing ends of the elongate member.  FIG. 10  shows three twists  2616 . However, other numbers of twists (e.g., 1-5, 6-10, greater than 10) are also possible. In this embodiment, the twists  2616  act as the “spring portion” to confer laterally directed pressure to tissue contact surfaces  2608   a ,  2608   b.    
     It may be desirable to be able to easily modify the properties of the elongate member  2602 . For example, the anatomical dimensions or characteristics of the uterus or medical conditions of a patient may call for adjustments to the outward force produced by the device  2600 . In such applications, the location of the twists along the middle portion  2604 , the number of the twists  2616 , and the tightness of the twists  2616  may be used to provide variability in the properties of the device  2600 . For example, increasing the number of twists  2616  may increase the stiffness of the elongate member  2602 ; and decreasing the number of twists  2616  may decrease the stiffness of the elongate member  2602 . For another example, increasing the tightness of the twists  2616  may increase the stiffness of the elongate member  2602 . Decreasing the tightness of the twists  2616  may decrease the stiffness of the elongate member  2602 . Moving the twists  2616  up along the middle portion  2604  may increase the stiffness of the elongate member  2602 ; and moving the twists down along the middle portion  2604  may decrease the stiffness of the elongate member  2602 . With the device of  FIG. 10 , a variety of differently configured devices can be made available to physicians to apply in the appropriate circumstances. The variability provided by the twists also allows much easier and more continuous customization of properties by merely modifying the nature of the twists, rather than the thickness or material of the wire itself to produce similar variations in properties. Wires come in standard sizes and materials, and if some intermediate is desired, the expense can make producing such a modified device impractical. Controlling properties of the device with the properties of the twists  2616  resolves this issue. 
     Referring now to  FIG. 11 , as mentioned above, one drawback with current IUDs is that delivery of the IUD through the cervix into the uterus can be uncomfortable or even painful. Additionally, currently available IUDs typically require a physician or assistant to load the IUD into the delivery device in the clinic, because preloading the IUD will typical deform the material it is made of and thus adversely affect its ability to stay in the uterus. In one embodiment, an IUD delivery device  2400  may be configured to address at least some of these drawbacks. Delivery device  2400  may include a tubular shaft  2402  (or “sheath”), a tapered distal tip  2404 , a pusher member  2410  disposed at least partially within shaft  2402 , and a handle  2406 . A retrieval string  2405 , which is part of the IUD, may extend out the proximal end of the delivery device  2400 . 
     Delivery device  2400  and its combination with the IUD embodiments described above may have a number of advantages over currently available devices. First, the shape memory IUDs described herein may typically be preloaded into shaft  2402  without causing permanent deformation of the IUDs. This enhances ease of use, since currently available devices typically must be loaded by the physician. Second, the IUDs described herein may be preloaded by advancing the IUD into a proximal end of delivery device  2400 , rather than by pulling the IUD into the distal end of a delivery device, as currently available devices work. Since delivery device  2400  is preloaded proximally, it may include tapered distal tip  2404 , which will likely be more comfortable when advanced through the cervix. In contrast, when the physician has to load the IUD by pulling it into the distal end of a delivery device in the clinic, such a tapered distal tip  2404  is not feasible. 
     The outer diameter of the shaft  2402  may be made smaller than currently available devices, because the shape memory IUDs described above are generally collapsible to fit in a smaller inner diameter. In some embodiments, for example, an IUD such as those described above may be collapsible to a diameter that permits shaft  2402  to have an outer diameter of between about 2.80 mm and about 3.40 mm, and more preferably between about 2.95 mm and about 3.20 mm. Fourth, although not visible in  FIG. 11 , an inner wall of the shaft  2402  may have slots for guiding/orienting an IUD within the delivery device  2400 . Such slots may help with delivery of the IUD, because the physician will know, based on the position of the delivery device  2400  relative to the patient, what the orientation of the IUD is. Again, this is not a feature of currently available IUD delivery devices, and such guiding/orienting with slots would not generally be possible when the physician must load the IUD into the delivery device in the clinic. In some embodiments, the pusher member  2410  may also have one or more guiding/orienting features, such as protrusions to fit within the slots of the inner wall of the shaft  2402 . In some embodiments, one or more markings may also be included on the shaft  2402 , pusher member  2410  and/or handle  2406  for helping guide/orient an IUD for facilitating delivery. 
     Various embodiments of a contraceptive intrauterine device and methods for using it have been disclosed above. These various embodiments may be used alone or in combination, and various changes to individual features of the embodiments may be altered, without departing from the scope of the invention. For example, the order of various method steps may in some instances be changed, and/or one or more optional features may be added to or eliminated from a described device. Therefore, the description of the embodiments provided above should not be interpreted as unduly limiting the scope of the invention as it is set forth in the claims. 
     Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.