Women have always practiced birth control, but it wasn't until the 1960s that hormonal control of ovulation became available. Initially, estrogen and progesterone were available only in pill form, but hormonal control is now also accomplished by injection, implant, patch and cervical ring. All methods prevent ovulation by maintaining sex hormones at high levels throughout a woman's cycle. Many residual effects have been noted from hormonal birth control, especially in pill form, which has been the most studied.
Residual Sexual Effects
The birth control pill was touted as being a sexual liberator by allowing women to enjoy sex without the concern of impregnation, although there is evidence that its residual effects may actually reduce sexual desire and pleasure. The "Journal of Sexual Medicine" published a clinical trial in 2006 that studied 124 women who were taking oral contraceptives for many years. The researches concluded that long-term use of oral contraceptives affected testosterone levels which caused unwanted residual effects, such as reduced sexual desire, difficulty with arousal and insufficient lubrication due to reduced vaginal secretions. Because of these residual effects, most of the women reported pain with sexual intercourse due to the lack of lubrication, and overall less sexual satisfaction.
Cancer-Causing Effects
The most serious residual effect of long-term use of oral contraceptives is cancer. Certain cancers, such as breast cancer, proliferate in the presence of elevated levels of sex hormones, such as estrogen. The National Cancer Institute confirms some clinical trials have shown that taking oral contraceptives increases the risk of breast cancer, although it notes that other studies concluded that there is no risk increase. The Institute cites that risks of cervical and liver cancers are elevated in oral contraceptive users.
There is agreement, however, in which cohort of women might be at the greatest risk of breast cancer and other cancers, and those are women older than 45 years who have been taking oral contraceptives for the majority of their adult lives, according to "Women and Cancer." These women have elevated risk because of long-term use and because the pills used to have higher estrogen content.
Cancer Protecting Effects
There are other cancers, however, that are deterred by elevated levels of sex hormones, which occurs when taking any form of hormonal birth control. For example, the National Cancer Institute cites that many studies indicate a reduced risk of ovarian and endometrial cancers in women on birth control pills. In particular, a 1992 analysis of 20 studies of oral contraceptive use conducted at Harvard Medical School found that that the risk of ovarian cancer decreased with increasing duration of birth control pill use. Results showed a 10 to 12 percent decrease in risk after one year of use, and a 50 percent decrease in risk after five years of use.
Cardiovascular Residual Effects
A 1989 study published in the "International Journal of Fertility" notes that other residual effects are experienced from short-term and long-term use of birth control pills and include increased risk of blood clots, myocardial infarction and stroke. Many of these residual effects are enhanced by cigarette smoking, which is why doctors recommend not smoking while on oral contraceptives. Low-dose estrogen pills, called the mini-pill, cause far fewer cardiovascular effects. The length of time that elevated levels of sex hormones can cause residual effects depends greatly on the user, but is thought to be many months to a couple of years.
References
- "Journal of Sexual Medicine"; Impact of Oral Contraceptives on Sex Hormone Binding Globulin and Androgen Levels: A Retrospective Study in Women with Sexual Dysfunction; Claudia Panzer M.D. et al; January, 2006
- U.S. National Cancer Institute: Oral Contraceptive and Cancer Risks
- "Women and Cancer"; Laurie Elit; 2006
- "Obstetrics and Gynecology"; A quantitative assessment of oral contraceptive use and risk of ovarian cancer; S.E. Hankinson et al; April, 1992
- "International Journal of Fertility"; Cardiovascular effects of oral contraceptives: a review; 1989
