Birth Control Pill

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.