Comparison of birth control methods
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Different types of birth control methods have large differences in effectiveness, actions required of users, and side effects.
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[edit] 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, and every twelve weeks for the injection Depo-Provera.
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 surgery, no action at all is required of users.
[edit] 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 the Lactational Amenorrhea Method (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 people and organizations disagree.[1][2]
Intrauterine methods often cause pain and changes in bleeding patterns.
Because of their systemic nature, hormonal methods have the largest number of possible side effects.
[edit] 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.
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.
[edit] 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 and sterilization fall into this category. For methods that are not user dependent, the actual and perfect-use failure rates are very similar.
Both the hormonal methods of birth control, and the Lactational Amenorrhea Method (LAM, breastfeeding infertility) require a moderate level of thoughtfulness. For 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. 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.
[edit] Effectiveness of various methods
- The table below color codes the Perfect-use failure rates as:
-
under 1% Green ultra low risk up to 5% Yellow low risk up to 10% Orange medium risk over 10% Red high risk
Many 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.[3] 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 of birth control methods (chance of pregnancy per year) | |||
|---|---|---|---|
| Birth control method | Type | Typical failure rate (%) | Perfect-use failure rate (%) |
| Norplant (synthetic progesterone implant) | Hormonal | 0.05 | 0.05 |
| IntraUterine System (e.g. Mirena) | Intrauterine & Hormonal | 0.1 | 0.1 |
| Male sterilization | Sterilization | 0.15 | 0.1 |
| Combined oral contraceptive pill ("COCP" estrogen/progesterone, "The Pill") |
Hormonal | 2.15-8 | 0.1 |
| Depo Provera (synthetic progesterone injection) | Hormonal | 0.3 | 0.3 |
| Female sterilization | Sterilization | 0.5 | 0.5 |
| Progesterone only pill ("POP", "minipill") | Hormonal | 5 | 0.5 |
| Intrauterine device (e.g. Copper T) | Intrauterine | 0.8 | 0.6 |
| Contraceptive patch ("The Patch") | Hormonal | 1-2 | 1 |
| NuvaRing | Hormonal | 2 | 1 |
| Male latex condom | Barrier | 15 | 2 |
| Fertility awareness1 (basal body temperature, cervical mucus) |
Periodic abstinence | 3-25 | 1-3 |
| Lactational Amenorrhea Method2 |
Natural | 2 | 0.5 |
| Withdrawal (coitus interruptus) | Natural | 19 | 4 |
| Female condom | Barrier | 21 | 5 |
| Diaphragm and spermicide | Barrier | 20 | 6 |
| Lea's shield | Barrier | 15,3 4.44 | Not available |
| Cervical cap and spermicide5 | Barrier | 16 | 9 |
| Vaginal sponge and spermicide5 | Barrier | 16 | 9 |
| Rhythm Method | Periodic abstinence | 25 | 9 |
| Gel / foam / suppository / film | Spermicide | 29 | 18 |
| Vaginal sponge and spermicide6 | Barrier | 32 | 20 |
| Cervical cap and spermicide6 | Barrier | 32 | 26 |
| None (unprotected intercourse) | N/A | 85 | 85 |
Note 1: Sometimes used interchangeably with natural family planning (NFP), though NFP refers specifically to family planning methods sanctioned by the Roman Catholic Church.
Note 2: Pregnancy rate is for first six months of use (method becomes less effective when used beyond six months post-partum), or until first postpartum menstruation (method is no longer effective after menstruation resumes).[4]
Note 3: There exists only a clinical trial with a sample of 59 women (17% nulliparous), with spermicide.[5]
Note 4: Same data, if population is standardized in terms of parity (this rate is lower because of low index of nulliparous women in the study)[6]
Note 5: Nulliparous women (women who have not given birth).
Note 6: Parous women (women who have given birth).
[edit] References
- Hatcher, RA, Trussel J, Stewart F, et al (2000). Contraceptive Technology, 18th Edition, New York: Ardent Media. ISBN 0-9664902-6-6.
[edit] Footnotes
- ^ Bloomquist, Michele (May 2000). Getting Your Tubes Tied: Is this common procedure causing uncommon problems?. MedicineNet.com. WebMD. Retrieved on 2006-09-25.
- ^ Hauber, Kevin C.. If It Works, Don't Fix It!. Retrieved on 2006-09-25.
- ^ Kestelman P, Trussell J. "Efficacy of the simultaneous use of condoms and spermicides.". Fam Plann Perspect 23 (5): 226-7, 232. PMID 1743276.
- ^ Comparison of Effectiveness. Planned Parenthood (April 2005). Retrieved on 2006-08-12., which cites Hatcher.
- ^ Birth Control Guide. FDA Consumer. U.S. Food and Drug Administration (December 2003). Retrieved on 2006-08-12.
- ^ FDA Approves Lea's Shield. The Contraception Report. Contraception Online (June 2002). Retrieved on 2006-08-13.
