Birth Control Pills
Birth control pills (oral contraceptives) are a highly effective form of contraception. When taken correctly, they prevent pregnancy in about 99 percent of women. Additionally, the pills offer other health benefits such as reducing heavy bleeding and painful cramping.
Birth control pills commonly contain estrogen and progesterone hormones. They may prevent pregnancy by preventing ovulation (release of the egg from the ovary) or by changing the lining of the uterus and the consistency of the cervical mucus.
Any woman who desires to prevent pregnancy may consider using birth control pills if medically appropriate. Women may also benefit from taking birth control pills if they have other conditions such as heavy or painful menstrual periods, a diagnosis of endometriosis LINK, premenstrual syndrome LINK or polycystic ovarian syndrome.
Taking birth control pills also decreases a woman’s risk of ovarian cancer. Data analysis of birth-control pill use in more than 23,000 women with ovarian cancer and 87,000 women without ovarian cancer suggests that a woman's risk of ovarian cancer decreases by 58 percent with 15 years’ use, 44 percent with 10 to 14 years’ use, 36 percent with five to nine years’ use, and 22 percent with one to four years of use.
If a woman takes a birth control pill perfectly (same time, every day, no missed pills), the possibility that she becomes pregnant is 0.1 percent each year. In other words, one of 1,000 women taking birth control pills on this schedule would become pregnant. The actual likelihood of pregnancy while on birth control pills is slightly higher because many women forget to take the pill. If several pills are missed in one month, they may not effectively prevent pregnancy.
If you miss one birth control pill, take it as soon as you remember. It is OK to take two birth control pills at the same time if you notice that you missed a day. Birth control pills probably are effective when one pill is missed, but this is not guaranteed.
If you miss two birth control pills, take two pills as soon as you remember, and two pills the following day to catch up. Continue to take your pills daily, but use a backup method of birth control, such as condoms, during this month.
If you miss more than two birth control pills, call the clinic to discuss what to do next.
Some women who have significant symptoms (bleeding, cramping, or migraine headaches) with their menstrual cycles, or who choose not to have periods, take their birth control pills continuously. (Skipping the week of non-active pills, and starting the next pack, prevents the ovary from releasing an egg and prevents a menstrual period.) Continuous use of birth control pills usually is recommended only with pills that have low dosages of hormones. If you are interested in this approach, talk with your physician to ensure you are on an appropriate pill and that you have the right instructions.
Birth control pills are generally well tolerated. However, women who have any of the following conditions are not good candidates for birth control pills and should consider other options.
- History of migraine headaches
- Seizure disorder on anticonvulsant medications
- Previous blood clot or stroke
- Active liver disease
- Breast cancer or other cancers
- Undiagnosed abnormal uterine bleeding LINK (talk to your physician)
- High cholesterol
- Women over age 35 years who smoke
Most women tolerate birth control pills well, but some women notice nausea, bloating or mood changes. Many women also notice some spotting or irregular bleeding when they are starting on birth control pills, which often resolves over a span of months.
Birth control pills can place you at higher risk for blood clots and pulmonary embolism (blood clots that travel to your lungs). In general, these risk levels are lower than those of patients who are pregnant. If you are taking birth control pills and develop calf pain, shortness of breath or chest pain, you should call your physician right away.
Birth control pills can interfere with other medications that can make one or the other less effective. To avoid such scenarios and to minimize the risk of unplanned pregnancy, tell your physician the names and dosages all of the medications you take.