Oral contraceptive

Oral contraceptives are chemicals taken by mouth to inhibit normal fertility. All act on the hormonal system. Female oral contraceptives have been on the market since the early 1960s, and enjoy great popularity. They are used by millions of women around the world, though the acceptance varies by region: approximately one-third of sexually active women in the United Kingdom, but much less in countries such as Japan. Male oral contraceptives remain a subject of research and development, and are not widely available to the public.

Mechanism of action

The Pill prevents pregnancy in three ways. It works primarily by preventing ovulation, but it also makes the uterus less likely to accept implantation of an embryo if one is created. The synthetic hormones thicken the mucus in the cervix making it more difficult for sperm to reach any egg.

Related Topics:
Ovulation - Uterus - Cervix

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Several different types of 'the Pill' exist. Generally, they all have different synthetic estrogens and progestins, chemical analogues of the natural hormones: estradiol (an estrogen) and progesterone (a progestagen). Most common brands use 20 to 40 micrograms of ethinyl estradiol as the estrogen component and either a fixed or varying (the bi- and triphasic pills) amount of either levonorgestrel or norethindrone as the progestagen component.

Related Topics:
Hormone - Estradiol - Estrogen - Progesterone - Progestagen - Ethinyl estradiol - Levonorgestrel - Norethindrone

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Please see Progesterone only pills which, lacking any estrogen, have much less of the side-effects and complications that apply to combined pills.

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