Like the patch and the vaginal ring, birth control pills rely on a combination of two artificially generated natural hormones to inhibit the natural cyclical process of reproduction. By adding small amounts of progesterone (a.k.a. progestin) and estrogen into a woman's body, the birth control pills prevent her from releasing an egg into the ovary and also diminish the effectiveness of the cervical mucus as a receptacle for the egg, should it still somehow bypass the pill's preventative actions.

Types of Birth Control Pills

Very few methods of birth control are more statistically effective than the pill. Used properly, it is considered 99.9% effective. A variation of the birth control pill called the mini-pill contains only progestin, not estrogen. These are designed mainly for women who are breastfeeding or who have had experienced too adverse a reaction to the full-strength contraceptive. Another, newer option is the extended-cycle pill, which reduces a woman's annual number of periods from the standard 13 to just four. The brand Seasonale uses a 13-week cycle of pills, with 12 weeks of active medication followed by one week of inactive medication. At that latter stage is when the women on these pills experience their seasonal period.

Birth Control Pills Alter Sexual Attraction?

Because birth control pills are such a powerful medication, some of the ways they work on women are only just now being ascertained. One of the more fascinating findings in recent years is that the medications may in fact alter how they are attracted to men. Normally, women are said to be attracted to the scent of a man who has a histocompatibility complex (MHC) that is different from theirs. However, a study found that the birth control pill could tip them instead towards men who share the same general MHC. It may have something to with an instinct to want for a "nurturing relative", but a separate study found that when women are paired with these same-MHC male partners, they are less sexually satisfied and more likely to cheat.

Possible Link between Birth Control Pills and Cancer

Another area of great variances in data is the relationship between taking the pill and the onset of cervical or breast cancer. One of the more frightening recent findings is that women who had been on the birth control pill within a year of a breast cancer diagnosis had a 60% higher risk of dying from the disease than those who were not on the pill.