Comparison of birth control methods

# Overview
Different types of birth control methods have large differences in effectiveness, actions required of users, and side effects.

# Ease of use
Different methods require different actions of users.  Barrier methods, spermicides, and withdrawal must be used at every act of intercourse.  The male condom may not be applied until the man achieves an erection.  Other barrier methods (cervical barriers, contraceptive sponge, and female condom) may be placed several hours before intercourse begins.  Spermicides, depending on the form, may be applied several minutes to an hour before intercourse begins.
Oral contraceptives, periodic abstinence methods, and the lactational amenorrhea method (LAM), require some action every day. Other hormonal methods require less frequent action - weekly for the patch, monthly for the vaginal ring or combined injectable contraceptive, and every twelve weeks for the injection Depo-Provera.
Implants are good for several years.  Intrauterine methods require clinic visits for removal and replacement (if desired) only once every few years (3-10, depending on the device).  Sterilization is a one-time, permanent procedure - after the success of surgery is verified, no action is required of users.

# Side effects
Different forms of birth control have different potential side effects.  Not all, or even most, users will experience side effects from each method.
Minimal or no side effects are possible with withdrawal, periodic abstinence, and LAM.  Some forms of periodic abstinence encourage examination of the cervix; insertion of the fingers into the vagina to perform this examination may cause changes in the vaginal environment.  Following the rules for LAM may delay a woman's first post-partum menstruation beyond what would be expected from different breastfeeding practices.
Barrier methods have a risk of allergic reaction.  Users sensitive to latex may use barriers made of less allergenic materials - polyurethane condoms, or silicone diaphragms, for example.  Barrier methods are also often combined with spermicides, which have possible side effects of genital irritation, vaginal infection, and urinary tract infection.
Sterilization procedures are generally considered to have low risk of side effects, though some persons and organizations disagree.
After IUD insertion, menstrual periods are often heavier, more painful, or both - especially for the first few months after they are inserted.
Because of their systemic nature, hormonal methods have the largest number of possible side effects.
The less effective the method, the greater the risk of the side-effects associated with pregnancy.

# Effectiveness calculation
Failure rates may be calculated by either the Pearl index or a life table method. A "perfect-use" rate is where any rules of the method are rigorously followed, and (if applicable) the method is used at every act of intercourse.
Actual failure rates are higher than perfect-use rates for a variety of reasons:
- mistakes on the part of those providing instructions on how to use the method
- mistakes on the part of the method's users
- conscious user non-compliance with method.
- insurance providers sometimes impede access to medications (e.g. require prescription refills on monthly basis)
For instance, someone using oral forms of hormonal birth control might be given incorrect information by a health care provider as to the frequency of intake, or by mistake not take the pill one day, or simply not bother to go to the pharmacy on time to renew the prescription, or the pharmacy might be unwilling to provide enough pills to cover an extended absence.

# User dependence
Different methods require different levels of diligence by users.  Methods that require a clinic visit less than once per year are said to be non-user dependent.  Intrauterine methods, implants and sterilization fall into this category.  For methods that are not user dependent, the actual and perfect-use failure rates are very similar.
Many hormonal methods of birth control, and LAM require a moderate level of thoughtfulness.  For many hormonal methods, clinic visits must be made every three months to a year to renew the prescription.  The pill must be taken every day, the patch must be reapplied weekly, or the ring must be replaced monthly.  Injections are required every few months.  The rules for LAM must be followed every day.  Both LAM and hormonal methods provide a reduced level of protection against pregnancy if they are occasionally used incorrectly (rarely going longer than 4-6 hours between breastfeeds, a late pill or injection, or forgetting to replace a patch or ring on time).  The actual failure rates for LAM and hormonal methods are somewhat higher than the perfect-use failure rates.
Higher levels of user commitment are required for other methods. Barrier methods, withdrawal, and spermicides must be used at every act of intercourse.  They do not provide any protection from pregnancy if they are not used.  Periodic abstinence methods require daily tracking of the menstrual cycle.  They also do not provide any protection from pregnancy if incorrectly used.  The actual failure rates for these methods are much higher than the perfect-use failure rates.

# Effectiveness of various methods
The table below color codes the Typical-use and Perfect-use failure rates as:
Some methods may be combined for higher effectiveness rates.  For example, simultaneously using both the male condom and spermicide (applied separately, not pre-lubricated) is believed to reduce perfect-use pregnancy rates to those seen among implant users.
If a method is known to have been ineffective (such as a condom breaking), emergency contraception may be taken up to 72 hours after sexual intercourse.

## Comparison table
This table lists the chance of pregnancy during the first year of use.

## References for effectiveness rates
- Combined injectable contraceptive: "FDA Approves Combined Monthly Injectable Contraceptive". The Contraception Report. Contraception Online. June 2001. Retrieved 2008-04-13..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- Jadelle: Sivin I, Campodonico I, Kiriwat O;  et al. (1998). "The performance of levonorgestrel rod and Norplant contraceptive implants: a 5 year randomized study". Hum. Reprod. 13 (12): 33718. PMID 9886517.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
- Lea's Shield: Mauck C, Glover LH, Miller E;  et al. (1996). "Lea's Shield: a study of the safety and efficacy of a new vaginal barrier contraceptive used with and without spermicide". Contraception. 53 (6): 32935. PMID 8773419.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
- Prentif cervical cap:Trussell, James (2004). "Contraceptive Efficacy".  In Hatcher, Robert A.;  et al. Contraceptive Technology (18th rev. ed. ed.). New York: Ardent Media. pp. pp. 773-845. ISBN 0-9664902-6-6.CS1 maint: Explicit use of et al. (link) CS1 maint: Extra text (link)
All other methods: Trussell, James (2007). "Contraceptive Efficacy".  In Hatcher, Robert A.;  et al. Contraceptive Technology (19th rev. ed. ed.). New York: Ardent Media. ISBN 0-9664902-0-7.CS1 maint: Explicit use of et al. (link) CS1 maint: Extra text (link)