Oral contraception (“OCPs”) uses hormones similar to natural estrogen and progesterone but of greater potency. When taken orally these cause the pituitary to cease producing the ovarian stimulatory hormones LH and FSH, thus shutting down ovulation. They also inhibit the formation of the mucus that allows ejaculated sperm to travel into the uterus and make the lining of the uterus inhospitable to pregnancy. This combination of three effects provides very effective and reliable contraception.
Oral contraception requires the patient to take one pill daily, at about the same time. The rule my patients learn is to take a pill at the same time daily; if you forget one, take it as soon as you remember. Most OCP therapy uses 21 active and 7 inactive pills, to permit menses in the fourth week and assure the patient that she is not pregnant. High concentrations of hormones in the OCPs that were used decades ago made this necessary to avoid side effects. Modern OCPs have doses a half to a tenth of those used in the 1960’s and can safely be used continuously. If active pills are taken daily, OCPs will prevent menstruation entirely without impairing future fertility. This is an enormous benefit to women with painful menstruation or with heavy menstrual bleeding.
Benefits Of Oral Contraception
While the main benefit of OCPs is the prevention of pregnancy, oral contraceptives may be used to treat other medical conditions, including:
- Abnormal uterine bleeding, Endometriosis and Dysmenorrhea (painful uterine bleeding), by limiting menstrual flow or preventing menses.
- Acne, Hirsutism (abnormal hair growth) and Polycystic ovary syndrome, by shutting off ovarian testosterone production.
- Prevention of pelvic cancer. Women who use OCPs in their 20-30s for at least five years have a 70% reduction in ovarian cancer and a 50% reduction in uterine cancer after menopause. This appears to be due to cessation of ovulation, with its attendant rupture and repair of the ovarian skin; and of reduced tissue growth within the uterus during the menstrual cycle.
Some OCPs may be used for emergency contraception if taken within 72 hours of unprotected sexual intercourse.
Risks Of Oral Contraception
Oral contraception is generally safe but there are risks to all medicines. OCPs are the most-studied medicine in history and risks have been greatly reduced by the steady reduction of doses over 60 years. Problems are rare in young women but increasingly likely in those who are smokers, overweight, hypertensive, or over age 40. These include:
- Irregular menstrual bleeding
- Abnormal blood clotting
- Weight gain
- High blood pressure
- Growth of benign liver nodules (hepatic adenoma); this is rare, I have seen one case ever.
Hormonal methods of birth control do not protect against HIV or other sexually transmitted diseases. Women using OPCs who have new or multiple male partners should use condoms as well to protect against STDs.