The cervical cap is one of the least common forms of contraception. It is a latex or silicone covering that fits over a woman’s cervix, in order to prevent sperm from entering the uterus. The effectiveness of this method depends upon which type of cap is used, who is using it, and whether or not it is used consistently and correctly. For example, the annual failure rate of the cervical cap for women who have given birth is between 32 and 26 percent for typical and perfect use. However, among women who have never given birth, it is between 16 and 9 percent. The difference in the rates is because childbirth alters a woman’s cervix, making the cap less effective. However, not all women can use this method of birth control. In fact, cervical caps do not fit 20-40 percent of women.
Historically, many cultures have attempted to create devices that cover the cervix as a method of birth control. These primitive barrier methods were made from everything imaginable, including beeswax, seaweed, lemon halves, paper, tree bark, tree roots, rock salt, and other items.
The potential side effects of the cervical cap are few, but may include urinary tract infection, toxic shock syndrome, and allergic reaction. Since the device blocks the sperm from entering the uterus, the woman is also deprived of its beneficial effects. For example, a man’s seminal fluid includes at least two dozen ingredients, including estrogens, follicle-stimulating hormone, luteinizing hormone, testosterone, transforming growth factor beta, and several different prostaglandins. During intercourse the female’s body absorbs these, and they aid the health of the woman.
Furthermore, when a man and woman have intercourse, the woman’s body becomes accustomed to the man’s sperm. In medical terms, her immune system develops a gradual tolerance to the antigens on his specific type of sperm and seminal fluid. For several hours after intercourse, a woman’s immune cells will collect and transfer a man’s foreign proteins and entire sperm cells from her cervix to her lymph nodes, where her immune system learns to recognize his genes.
However, if the couple decides to use a barrier method of birth control for an extended period of time before having children, the womb will not be accustomed to the sperm, and the woman’s immune system may treat them as foreign bodies. This can disrupt the delicate balance of hormones and cause the woman’s blood vessels to constrict, leading to higher blood pressure in the expectant mother. This condition (preeclampsia) occurs in about 5 to 8 percent of all pregnancies and can lead to premature delivery of the baby. Unfortunately, pre-term babies are more likely to experience learning disabilities, cerebral palsy, epilepsy, blindness, and deafness. Preeclampsia can also be dangerous for the mother: it is the third leading cause of maternal death during childbirth.
It has been demonstrated that a man’s semen offers a protective effect against preeclampsia, because it makes the woman’s immune system more likely to recognize his baby. According to The Journal of the American Medical Association, preeclampsia is more than twice as common in women who used barrier methods of contraception. So in a certain sense, couples who use the cervical cap are having “unprotected” sexual intercourse, because the man is not protecting the woman’s body with the beneficial effects of his semen.
. Hatcher, et al., Contraceptive Technology 18th ed. (New York: Ardent Media, 2000).
. Secor, “The cervical cap,” NAACOG’s Clinical Issues in Perinatal and Women’s Health Nursing 3:2 (1992): 236-245.
. “A History of Birth Control Methods,” Planned Parenthood (June 2002); “Evolution and Revolution: The Past, Present, and Future of Contraception,” The Contraception Report 10:6 (February, 2000): 15.
. G.G. Gallup, Jr., et al., “Does Semen Have Antidepressant Properties?” Archives of Sexual Behavior 31:3 (June 2002), 289–293; P.G. Ney, “The Intravaginal Absorption of Male Generated Hormones and Their Possible Effect on Female Behaviour,” Medical Hypotheses 20:2 (June 1986), 221–231; Herbert Ratner, “Semen and Health: The Condom Condemned,” Child and Family (1990); C. J. Thaler, “Immunological Role for Seminal Plasma in Insemination and Pregnancy,” American Journal of Reproductive Immunology 21:3–4 (November/December 1989), 147–150.
. Ratner; Ney, 221–231.
. S.A. Robertson, et al., “Transforming Growth Factor Beta—A Mediator of Immune Deviation in Seminal Plasma,” Journal of Reproductive Immunology 57:1–2 (October/November 2002), 109–128.
. Douglas Fox, “Gentle Persuasion,” New Scientist (February 9, 2002); Douglas Fox, “Why Sex, Really?” U.S. News and World Report (October 21, 2002), 60–62.
. S.A. Robertson, et al., “The Role of Semen in Induction of Maternal Immune Tolerance to Pregnancy,” Seminars in Immunology 13 (2001), 243; John B. Wilks, A Consumer’s Guide to the Pill and Other Drugs, 2nd ed. (Stafford, Va.: American Life League, Inc., 1997), 136.
. A. Hirozawa, “Preeclampsia and Eclampsia, While Often Preventable, Are Among Top Causes of Pregnancy-Related Deaths,” Family Planning Perspectives 33:4 (July/August 2001), 182; Andrea Mackay, et al., “Pregnancy-Related Mortality From Preeclampsia and Eclampsia,” Obstetrics & Gynecology 97 (2001), 533–538.
. H. S. Klonoff-Cohen, et al., “An Epidemiologic Study of Contraception and Preeclampsia,” The Journal of the American Medical Association 262:22 (December 8, 1989), 3143–3147.
. S.A. Robertson, et al., “Seminal ‘Priming’ for Protection from Pre-Eclampsia: A Unifying Hypothesis,” Journal of Reproductive Immunology 59:2 (August 2003), 253–265; G.R. Verwoerd, et al., “Primipaternity and Duration of Exposure to Sperm Antigens as Risk Factors for Pre-eclampsia,” International Journal of Gynaecology and Obstetrics 78:2 (August 2002), 121–126; J. I. Einarsson, et al., “Sperm Exposure and Development of Preeclampsia,” American Journal of Obstetrics and Gynecology 188:5 (May 2003), 1241–1243; M. Hernandez-Valencia, et al., “[Barrier Family Planning Methods as Risk Factors Which Predisposes to Preeclampsia],” Ginecologia y Obstetrica de Mexico 68 (August 2000), 333–338; Dekker, et al., “Immune Maladaptation in the Etiology of Preeclampsia: A Review of Corroborative Epidemiologic Studies,” Obstetrical and Gynecological Survey 53:6 (June 1998), 377–382; H. S. Klonoff-Cohen, et al., “An Epidemiologic Study of Contraception and Preeclampsia,” The Journal of the American Medical Association 262:22 (December 8, 1989), 3143–3147.