Emergency contraception

Morning-after pill; Postcoital contraception; Birth control - emergency; Plan B; Family planning - emergency contraception

Emergency contraception is a birth control method to prevent pregnancy in women. It can be used:

  • After a sexual assault or rape
  • When a condom breaks or a diaphragm slips out of place
  • When a woman forgets to take birth control pills
  • When you have sex and do not use any birth control
  • When any method of birth control is not used correctly
Intrauterine device

The intrauterine device shown uses copper as the active contraceptive, others use progesterone in a plastic device. IUDs are very effective at preventing pregnancy (less than 2% chance per year for the progesterone IUD, less than 1% chance per year for the copper IUD). IUDs come with increased risk of ectopic pregnancy and perforation of the uterus and do not protect against sexually transmitted disease. IUDs are prescribed and placed by health care providers.

Side sectional view of female reproductive system

The female reproductive system includes the vagina, cervix, and uterus shown here in cut section.

Hormone-based contraceptives

The pill works in several ways to prevent pregnancy. The pill suppresses ovulation so that an egg is not released from the ovaries, and changes the cervical mucus, causing it to become thicker and making it more difficult for sperm to swim into the womb. The pill also does not allow the lining of the womb to develop enough to receive and nurture a fertilized egg. This method of birth control offers no protection against sexually-transmitted diseases.

Birth control methods

Artificial contraception methods work in different ways to decrease the likelihood that sexual intercourse will result in pregnancy. Barrier methods such as condoms (male or female), diaphragms (with or without spermicide) and sponges (with spermicide) have as their first line of defense the physical blocking of the sperm's entry into the uterus. If sperm cannot get into the uterus it cannot fertilize an egg, and pregnancy cannot occur. An IUD works in a different way, by making the uterus toxic to sperm and by disturbing the lining of the uterus so that it won't allow egg implantation. The hormones in oral contraceptives and hormone implants fool the ovaries into refraining from ovulation, and without a fertile egg, pregnancy will not occur. IUDs and oral contraceptives and hormones may be used as emergency contraception in the case of unprotected sex, but neither one will protect against sexually-transmitted disease.

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