Epigee Birth Control Guide
Oral Contraceptives
Combined Oral ContraceptivesProgestin-Only Pills
Emergency Contraceptive PillsFAQs about Hormonal Methods

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Did you know that hormonal contraceptives, like The Pill, have post-fertilization mechanisms?
(see info in box on right)

No, just learned of it now.
Yes, I already knew.
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How does this information affect your decision to use (or have your partner use) hormonal contraception?
makes me less likely to use or recommend
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Hormonal methods of birth control appear in many different forms and are extremely popular due to their ease of use and efficacy. These include oral contraceptives, injectables, and implants, all of which have multiple birth control mechanisms, including some which take effect after fertilization (see box below). There are also numerous side-effects and health risks which can be entirely avoided if the other methods of birth control discussed in this guide are used instead.

Average Failure Rate: 3 - 8%

Ortho Birth Control Pills The process of ovulation is directed by hormones. Estrogen and progesterone are two hormones which direct many of the processes surrounding the menstrual cycle. Artificial analogues of these have proven an efficient form of birth control. To prevent pregnancy a woman takes a pill daily which contains both of these hormones. This is the combination pill, or simply "the pill."

The estrogen works by preventing an egg from being released from the ovaries most of the time. Both the estrogen and progesterone make the uterus a hostile environment for an embryo by causing a thinning of the uterine lining. As modern combination pills contain less estrogen than their predecessors, an egg will be released by the ovaries 2-10% of the time. If fertilization takes the embryo will be unable to implant in the uterus, resulting in the death of the embryo. Although some consider this risk minimal, the most reliable sources cite the interceptive effect as a major mechanism of action; in fact, large doses of this drug are used as a 'morning after pill' (see the Emergency Contraceptive Pills below).

Oral contraceptives also have some uncommon but serious health risks associated with their use, especially among smokers; these include abnormal blood clotting and heart attacks, cancer, and gallbladder disease. Side effects include headaches, acne, weight gain, vaginal infections, and depression.

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What to Know about Hormonal Methods

Think "oral contraceptives" prevent conception? Think again. Hormonal methods suppress ovulation much of the time, but scientists recognize that in many cases ovulation continues to occur.[1] Some women who use hormonal methods ovulate every single cycle. So how do hormonal methods prevent conception? That depends on how you define "conception." Although most people think of conception as the joining of egg and sperm to form new life, in some circles the word "conception" has an alternate meaning--the implantation of the embryo into the uterus.[2] When fertilization is not prevented, hormonal birth control methods commonly cause the expulsion of an embryo prior to implantation by changing the lining of the uterus so that it will not accept an embryo and by changing the way the fertilized ovum travels down the fallopian tube.[3] This action has been termed by some as 'interceptive,' as opposed to contraceptive or abortive.[4] This is an important distinction, because any woman interested in preventing fertilization will want to avoid using these methods. Although there are legitimate medical uses for some of these drugs, clinicians tend not to explain the interceptive effects to their patients, some being unaware themselves. Pharmaceutical companies minimize this mechanism of hormonal methods to prevent women of conscience from rejecting their products, as had occurred with the IUD.[5]

1. WL Larimore, JB Stanford, Postfertilization Effects of Oral Contraceptives and Their Relationship to Informed Consent, Archives of Family Medicine, 2000;9:126-133. Go there, PDF version
2. The FDA and the American College of Obstetrics and Gynecology now define 'conception' to mean implantation instead of fertilization. Under this definition, all hormonal methods and IUDs would be contraceptive. JC Willke, Abortion: Questions and Answers, Revised 1990 Ed., Hayes Publishing Company Inc., Cincinnati, OH, 1990, p. 42-43.
3. RA Hatcher et al, Contraceptive Technology, 17th Ed., Ardent Media Inc., New York, 1998, p. 406, 468-9, Table 20-1.
4. RG Rahwan, "Pharmacological Approaches to Birth Control: Contraceptives, Interceptives, Abortifacients." U. S. Pharmacist, 1977, 10: 31-42. Course notes revisited 1995.
5. R Alcorn, see Section 10. "What do the Pill manufacturers say?" in "Does the birth control pill cause abortions?" 2nd ed., Eternal Perspective Ministries, Gresham, OR, 1998. Go there.

Average Failure Rate: 1 - 13%

Progestin based oral contraceptives, commonly referred to as "the mini-pill," contain progestin but no estrogen. The mini-pill works by changing the lining of the uterus which prevents the implantation of an embryo and inhibiting ovulation in some women. Many women taking the mini-pill will continue to ovulate every month, and those women who do cease ovulating will usually stop having periods altogether. The progestin may also cause a thickening of cervical mucus, making it harder for sperm to reach the egg. This effect on cervical mucus, however, starts to drop off sharply if a woman is only a few hours late in taking her next pill, thus it is critical that pills be taken at the same time every day.

Doctors tend to recommend the mini-pill to breastfeeding women because it does not reduce the amount of milk produced, although there have been concerns about exposing the new infant to unnecessary steroids. Mini-pills also considered safer than combined OCs, as many of the vascular risks are markedly reduced with the omission of the estrogen component. Health risks and side effects include ectopic pregnancy, depression, and menstrual cycle disturbances.


Emergency Contraceptive Pills (ECP), or The Morning-After "Pill," are actually a large dose of ordinary oral contraceptives taken after intercourse has occurred. ECPs were first used in the 1960's for rape victims, but the FDA now recommends oral contraceptives for emergency use when a woman has had unprotected intercourse within the previous 72 hours.

ECPs work in the same way as other hormonal methods, by suppressing ovulation, making the uterus inhospitable to the newly conceived human being, and interfering with the movement of the ovum. (See box above.) For women who have had unprotected intercourse and do not wish to use ECPs, it is suggested that immediately following unprotected intercourse a spermicidal agent be applied to reduce the probability of conception.

Emergency Contraceptive Pills can only be obtained from a doctor. The doctor may require that the patient sign a contract indicating that she is aware of the health risks and will consider abortion if the treatment fails, even though there is no evidence that oral contraceptive pills would harm the baby. ECPs are thought to be 75% effective. Common side effects are nausea and vomiting; health risks include increased risk of ectopic pregnancy.

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