Contraceptive cervical cap

A cervical cap for covering a portion of the cervix uteri in order to prevent migration of sperm from the vagina into the cervical canal to thereby prevent conception. The cervical cap has an open end portion, a dome-shaped portion, preferably sealed, disposed opposite the open end portion, and a ridged section designed to grip the cervix to secure the cap. In the preferred embodiments, the ridged section has a plurality of substantially parallel ring-shaped ridges formed on the interior surface of the cap. In an alternate embodiment, a helical-shaped ridge is formed on the interior surface of the cap and extends from the rim to the dome portion, progressively narrowing in width.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for covering a portion of the 
cervix uteri to prevent the migration of sperm from the vagina into the 
cervical canal and more particularly to a cervical cap having a ridged 
section adapted to grip the cervix, thus preventing dislodgement (or 
displacement) of the cap (or thus increasing cap stability). 
2. Description of the Related Art 
Cervical caps designed to cover a portion of the cervix uteri in order to 
prevent the migration of sperm from the vagina into the cervical canal and 
thereby prevent conception are known in the art. However, these known caps 
suffer several drawbacks and deficiencies. 
Known cervical caps create medical problems for the user, such as abnormal 
cramps, abnormal bleeding, abnormal discharge from the uterus, and mucosal 
erythema. Furthermore, known caps, due to their size and shape, cause 
discomfort for both the user as well as for the partner. 
Another problem encountered with prior cervical caps is the frequency with 
which they become dislodged from the cervix. These caps rotate on the 
cervix or slide from the surface of the cervix when the rim is gently 
pushed. The result of such dislodgement is not only increased discomfort 
but the defeat of the very purpose behind using the cervical cap because 
dislodgement allows sperm to migrate into the cervical canal which can 
result in conception. 
Therefore, attempts have been made to design a reliable cervical cap that 
securely fits around a portion of the cervix while still avoiding the 
aforementioned medical problems and the associated inconveniences and 
discomfort. Such attempts have taken a variety of forms. For example, some 
caps have been designed with a spring mechanism within the wall; some caps 
have been provided with adhesive to adhere the cap to the cervix (see, for 
example, U.S. Pat. No. 3,952,737); and some have been provided with 
projections on the inner surface. However, these caps have not only failed 
to solve the problems discussed above, but have created additional 
problems. For example, U.S. Pat. No. 3,952,737 discloses a cervical cap 
which is held to the cervix by an O-ring, notches, an internal bead and an 
inner sealing ring. This device, however, in attempting to solve the 
dislodgement problem, has resulted in a cap that is both expensive to 
manufacture due to its complexity and is difficult to use because it is 
inserted with an applicator and the 0-ring must be maneuvered from the 
bottom position to the top position after the cap has been placed on the 
cervix. 
A need therefore exists for a cervical cap that is comfortable and reliable 
as a contraceptive. Furthermore, a need exists for such a comfortable and 
reliable cap that is simple to use, is not prohibitively expensive, and 
does not adversely affect the health of the user. 
SUMMARY OF THE INVENTION 
The present invention overcomes the aforementioned problems and 
deficiencies in the art. The present invention provides an apparatus for 
covering a portion of the cervix uteri which comprises a cap having inner 
and outer surfaces and an open end portion. The inner surface has a ridged 
section which is adjacent to the open end portion. The ridged section is 
adapted to grip the cervix when the cap is placed over a portion of the 
cervix. The ridged section has first and second ridge portions projecting 
inwardly from the inner surface of the cap. The distance between the open 
end portion and the first ridge portion is less than the distance between 
the open end portion and the second ridge portion. 
More particularly, in one embodiment, the first and second ridge portions 
are substantially ring shaped and are disposed in substantially parallel 
relationship to each other. Preferably, the first ridge portion is formed 
at a rim of the cap. The inside diameter of the ridged section at the 
first ridge portion is substantially equal to the inside diameter of the 
ridged section at the second ridge portion. The cap may further include a 
third ring-shaped ridge disposed between the first and second ridges and 
in substantially parallel relationship to the first and second ridges. The 
cap preferably terminates in a rounded edge region at the open end 
portion. 
The cap may have a reduced diameter rim section relative to the diameter of 
the ridged section. Alternatively, the cap may have an enlarged diameter 
rim section relative to the diameter of the ridged section. A region of 
the cap adjacent to the ridged section may be tapered so that the inside 
diameter at that region is less than the inside diameter at the ridged 
section. The ridged section of the cap may also be tapered so that the 
distance between the inner and outer surfaces is greater at the first 
ridge portion than at the second ridge portion. 
In an alternate embodiment of the present invention, the first and second 
ridge portions of the cap are connected to form a continuous helical 
shaped ridge wherein the inside diameter of the cap at the ridged section 
remains substantantially constant or progressively decreases away from the 
open end portion. Preferably, the first ridge portion is formed at the rim 
of the cap. The cap may terminate at a rounded edge region at the open end 
portion. Alternatively, a flange-like projection is formed at the rim of 
the cap which extends outwardly from the open end portion. The ridged 
section of the cap may be tapered such that the distance between the inner 
and outer surfaces is greater at the first ridge portion than at the 
second ridge portion. 
The cap may further comprise a dome-shaped portion which is disposed 
opposite the open end portion and is preferably of substantially uniform 
thickness. The dome-shaped portion is preferably sealed and has an inside 
diameter which progressively increases towards the ridged section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the drawings, the several embodiments of the invention are shown in 
longitudinal cross-section. That is, the cap is essentially dome- or 
bell-shaped; the axis of rotation of the drawing lies in the plane of the 
drawing. Like reference numerals prefixed with the figure number represent 
corresponding parts in the several views. Thus, the cervical cap of the 
present invention is indicated generally by reference numeral 10 in FIG. 
1, by 20 in FIG. 2, by 30 in FIG. 3, and by 40 in FIG. 4. The cervical 
cap, made preferably of natural or resilient synthetic rubber, is inserted 
to cover the vaginal portion of the cervix uteri and is designed to be 
impenetrable in normal use so as to prevent sperm from migrating into the 
cervical canal, thereby preventing conception. 
In the embodiment shown in FIG. 1, the cervical cap 10 has an outer surface 
100 and an inner surface 110. The cervical cap 10 includes a dome portion 
120, a rim 130, and an opening 140. The opening 140, defined by the rim 
130, is disposed opposite the dome portion 120 and is of sufficient size 
to fit over the vaginal portion of the cervix uteri. The rim 130 has a 
rounded edge top portion 132 located at opening 140 where the cap 10 
terminates. 
The dome portion 120 is substantially semicircular in shape, and preferably 
has a uniform thickness measuring about 0.8 mm to about 1 mm, depending on 
the material used to construct the dome. The dome portion 120 is 
preferably sealed to effectively prevent the migration of sperm into the 
cervical canal. The dome portion 120 is tapered so that the inside 
diameter of the cap 10 progressively decreases toward a tip 122 of the 
dome. Preferably and advantageously, and depending on the size of the 
cervix, which varies widely among women and may change in a given woman as 
a result of childbirth, the inside diameter D1 at the widest section of 
dome portion 120 of the cap 10 may vary from about 22 mm to about 34mm. 
The height H of the cap 10, measured from opening 140 to tip 122, may vary 
from about 25 mm to about 40 mm. The inside diameter D2 of the rim 130 may 
vary from about 19 mm to about 32 mm. Therefore, a cervical cap is 
provided which advantageously combines small size, comfort, and 
reliability. 
The rim 130 has a circumferential ridge section 150 between top portion 132 
and dome portion 120. Section 150 contains a plurality of blunt edged 
ridges on its inner surface. The ridged section 150 effectively functions 
to secure cap 10 to the cervix by firmly but gently pressing against the 
surface of the cervix uteri. This uniquely shaped ridged section 150 helps 
to provide an airtight and substantially fluid-tight fit and prevents 
dislodgement of the cap which would cause an increase in the chance of 
conception. Preferably, a gel, cream, or foam-type spermicide is provided 
in the space defined by the dome portion 120 to provide further 
contraceptive protection. 
FIG. 1 illustrates the embodiment of the cervical cap 10 of the present 
invention having a ridged section 150 which comprises three ring-shaped 
ridges 152, 154, and 156. The three ring-shaped ridges 152, 154, and 156 
are preferably disposed in parallel relationship to each other with the 
outer ridge 152 forming a part of the rim 130 of the cap 10. A space or 
recess 153 is defined by a pair of substantially parallel walls 160 and a 
third wall 161 substantially perpendicular to the pair of walls 160 and is 
located between the outer ridge 152 and the middle ridge 154, and a space 
or recess 155, similar to recess 153, is defined between the middle ridge 
154 and inner ridge 156. The three ridges 152, 154, and 156 are preferably 
of equal width or thickness W so that the distance between the inner 
surface 110 and the outer surface 100 at each of the ridges 152, 154, and 
156 is approximately equal. In the preferred embodiment, W1 measures about 
4 mm. Preferably, the depth of each of the recesses 153 and 155 is about 
1.5 mm. The outside diameter E1 at the rim section 130 preferably measures 
about 28-40. 
Obviously, a range of appropriate cap sizes will be provided. Values for 
the cap diameters and ridge spaces will be selected to effectively secure 
the cap 10 to the cervix of the particular wearer. 
Finally, cap 10 as illustrated in FIG. 1 tapers slightly inwardly from the 
top portion 130 along section 132 adjacent the cap opening 140. 
The version of the cervical cap shown in FIG. 2 differs from that of FIG. 1 
primarily with respect to the shapes of the respective ridge sections. In 
the embodiment of FIG. 2, the ridge region 250 is thicker than the 
corresponding ridge region 150 in FIG. 1. Thus W2, the thickness of region 
250, is greater than W1. The portion 202 joining rim region 234 with dome 
region 220 has a longer taper than the corresponding portion 102 in FIG. 
1. Diameter E2, the outer diameter of rim 230 measures about 32-44 mm. 
Preferably, the thickness or width W2 of ridge region 250 decreases from 
the outer ridge 252 to the inner ridge 256, as shown in FIG. 2, to provide 
the desired combination of rigidity and flexibility. 
FIG. 3 illustrates yet another alternate embodiment of the cervical cap 
having parallel ring-shaped ridges to grip the cervix. The cap 30 has a 
ridged section 350 which includes an outer ridge 352, an middle ridge 354, 
and an inner ridge 356. A recess 353 is defined between outer ridge 352 
and middle ridge 354, and a recess 355 is defined between middle ridge 354 
and inner ridge 356. The ridged section 350 is tapered so that the 
distance between the inner surface 310 and outer surface 300 decreases 
from outer ridge 352 to inner ridge 356, whereby the width or thickness of 
ridges 352, 354, and 356 vary. In one specific example, the thickness T1 
between the outer and inner surfaces 300 and 310 at the outer ridge 352 is 
preferably about 5 mm, the thickness T2 between the outer and inner 
surfaces 300 and 310 at the middle ridge 354 is preferably about 4 mm, and 
the thickness T3 between the outer and inner surface 300 and 310 at the 
inner ridge 356 is preferably about 3 mm. Obviously, other dimensional 
relationships which achieve the same function and result are possible. 
The cervical cap embodiment in FIG. 3 is shown with a flange 336 extending 
outwardly from rim 330 away from opening 340. While the cap can be 
constructed in this way, the preferred versions do not include the flange 
336. In the more preferred versions, the rim is rounded, as the 
embodiments shown in FIGS. 1, 2, and 4. 
FIG. 4 illustrates another alternate embodiment of the cervical cap of the 
present invention. The cap 40 has a ridged section 450 which comprises a 
helical shaped ridge 452 formed on inner surface 410. The helical shaped 
ridge 452 enables the cap 40 to be screwed onto the exterior surface of 
the cervix to provide a secure fit. 
In the embodiment shown in FIG. 4, the helical-shaped ridge 452 extends 
from an inner portion 438 of rim 430. Rim 430 terminates preferably in a 
rounded edge region 432. Helical ridge 452 terminates at its inner end 
458, adjacent portion 402 which joins wall region 434 and dome region 420. 
The width or thickness W4 of ridge region 450 between the inner surface 
410 and outer surface 400 along the helical-shaped ridge 452 preferably 
remains substantially constant or continuously decreases away from opening 
440 until the inner portion 458 is flush with inner surface 440. A space 
or recess 457 is defined between the adjacent rows of helical ridge 452 by 
walls 160, 161 as described above. The inside diameter of the cap 10 at 
spaces 457 is from about 18 mm to about 35 mm. 
When the cervical cap of the present invention is inserted, preferably 
digitally or with a suitable insertion tool, over the vaginal portion of 
the cervix uteri, the substantially parallel walls 160 of the ridge 
section remain substantially fixed relative to each other and function to 
grip that portion of the cervix both firmly and gently to effectively 
prevent the dislodgement of the cap. There is no need for additional 
securing features, as the unique dimensions of the cap, including the 
shape and size of the dome, as well as the unique location and formation 
of the ridges secure the cap in position. Both the ring-shaped ridges and 
the helical-shaped ridge advantageously provide for easy insertion and a 
secure fit. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.