Effectiveness: 92 to 99.7 percent (effectiveness is near 100 percent if the pill is taken daily as directed; because many women do not use as directed, the pregnancy rate is 2-9 pregnancies per 100 women each year, and it may be slightly less effective if you're overweight).
What is it? Most birth control pills contain synthetic hormones similar to estrogen and progesterone produced by your body. Pills containing both hormones are known as combination pills; some pills only contain progestin and are known as the mini-pill (that option is described separately). Birth control pills typically come in packs with a month's supply, and you take one pill daily at about the same time of day. There are many types available, containing various types, amounts and combinations of hormones. Birth control pills are often referred to as “the pill" or oral contraception.
How does it work? Birth control pills release synthetic estrogen and progestin. These hormones keep you from releasing eggs so pregnancy cannot occur. The hormones also thicken your cervical mucus, blocking the sperm from reaching the egg, and affect the lining of the uterus, both of which may help prevent pregnancy.
STD protection: No; you will still need to use condoms if you are concerned about STDs.
Benefits: It's simple and convenient and allows women to feel more spontaneous about having sex. It may make your periods regular, lighter and shorter. Like other hormonal forms of birth control, the pill may offer some protection against acne; severe menstrual cramps; bone thinning; ectopic pregnancy; endometrial and ovarian cancers; iron deficiency anemia; serious infections in the ovaries, fallopian tubes and uterus; breast and ovarian cysts; pelvic inflammatory disease; and premenstrual symptoms. Your ability to get pregnant returns quickly when you stop using the pill.
Disadvantages: May cause nausea, breast tenderness, weight gain or loss, water retention, increased blood pressure, headaches, changes in mood or sexual desire. The combination pill is not recommended if you are pregnant or think you may be pregnant; have had breast cancer; are over 35 and smoke; or have certain other health conditions (see Notes below). Certain medicines and supplements may make the pill less effective, including the antibiotic rifampin, certain oral medicines taken for yeast infections, some HIV medicines, some anti-seizure medicines and St. John's wort. Vomiting and diarrhea may also prevent the pill from working. Serious complications are rare, but always talk with your health care provider about risks and benefits.
Availability: Prescription required.
Cost: $15 to $50 for a 1-month supply.*
Notes: Combination pills may be packaged to let you have a period monthly, every 3 months or not at all. Active pills taken continuously prevent you from getting your period, but you may have spotting or bleeding the first 6 months, lessening or stopping over time. The pill is not recommended for use during prolonged bed rest or if you are pregnant; have migraine headaches with aura; have blood clots or vein problems; have (or have had) breast or liver cancer; have had a heart attack, stroke or angina; have had serious heart valve problems; have certain hereditary blood-clotting disorders; have serious diabetes or liver disease; are 35 or older and smoke; or have high blood pressure and smoke. You should not take certain types of combination pills if you have ever had kidney, liver or adrenal gland disease. Women who use hormonal contraception are strongly advised not to smoke.
* The Affordable Care Act requires insurance companies to cover with no co-pay any FDA-approved contraceptive method prescribed by your doctor, including barrier methods, hormonal methods, implanted methods, emergency contraception, female sterilization and patient education and counseling. These estimated costs apply to women who do not have insurance coverage or who work for a "religious employer," who may be exempt from providing contraceptive coverage. For details about what your insurance covers, contact your benefits coordinator or health insurance provider.