The birth control pill, also known as an oral contraceptive or simply referred to as ?The Pill,? is hailed as one of the most important innovations in women's health. Before the advent of the Pill, many women were forced to endure multiple pregnancies because there were no reliable or convenient means of preventing conception. During the twentieth century, two women named Margaret Sanger and Katherine McCormick resolved to change this and funded the work of Gregory Pincus, a doctor who had been studying the role that hormones played in conception. A partnership with the pharmaceutical company Searle later resulted in Enovid, the first birth control pill approved by the Food and Drug Administration (FDA) for use in the United States. Five years later, the Comstock Law, which was passed in 1873 deeming contraception as illegal, was repealed, and millions of women began to exercise more control over their wombs. As the decades passed, continuous research and development has been carried out to improve the quality of these birth control pills.

There are currently three different kinds of birth control pills: progestin-only pills (POP), combination pills, and emergency contraceptive pills (ECP). Progestin-only pills, also known as ?mini-pills,? must be taken at a certain time every 24 hours. They contain no estrogen and primarily works by thickening the cervical mucus to prevent sperm from entering the uterus. This is ideal for women who cannot take estrogen or are currently breastfeeding. The second type of birth control pill is called the combination pill, because it contains both estrogen and progestin. This type of oral contraceptive comes in three variants: monophasic pills, which have 21 tablets containing equal amounts of both hormones and seven placebos that will be taken during menstruation; multiphasic pills, which contain varied amounts of the two hormones to be taken with a specific dosing schedule mirroring the menstrual cycle; and continuous use pills, which are designed to be taken successively without stopping between packets, thereby totally stopping the menstrual period.

The last type of oral contraception, called emergency contraceptive pills, is not to be taken regularly unlike other birth control pills. This latest innovation in pregnancy prevention is selling under the brand name Plan B, a drug which contains a synthetic progestin called levonorgestrel. Also known as ?the morning after pill,? Plan B was designed specifically for emergencies when a woman missed a dose of the pill before sex, a failure in other birth control methods such as a broken condom or displaced intrauterine device or after being sexually assaulted.

Plan B acts primarily to prevent pregnancy by stopping ovulation (the release of an egg from the ovary), fertilization (the union of a sperm and egg cell), or implantation (attachment of the fertilized egg) in the woman's womb. This is possible because conception rarely occurs immediately after intercourse, and is more likely to happen within several days after the sperm is released inside a woman's body. Plan B uses a two-dose regimen taken within 72 hours of the sexual intercourse to ensure that this does not happen, and is successful in about eighty percent (80%) of cases. Side effects may include nausea, vomiting, abdominal pain, fatigue and headache. This drug is currently only available with a doctor's prescription, although the FDA plans to make it widely available over the counter soon.