How Does Emergency Contraception Work?


A method to prevent pregnancy when you have an unexpected need is emergency contraception. Emergency contraception can be used up to 120 (5 days) after unprotected intercourse. The sooner you take emergency contraception after unprotected sex, the better chance it has of working. If taken in the first 24 hours after unprotected intercourse, it has a 95% rate of successful pregnancy prevention.

Some situations where a woman may need emergency contraception include:
• When a condom breaks, or comes off, including when it comes off inside the woman’s vagina.
• When a woman forgets to take her birth control pill for more than three days in a row.
• If a woman’s diaphragm or cervical cap slips out of place or is inserted incorrectly.
• If a woman has sex without any method of contraception.
• After a woman is sexually assaulted or raped.

Many people get emergency contraception confused with RU486, which is known as the abortion pill. But they are not the same thing. RU486 ends an already established pregnancy in the very early stages. Emergency contraception prevents a pregnancy from happening in the first place and will not disturb an already established pregnancy.

Emergency contraception works two different ways depending where in her menstrual cycle unprotected sex occurs. If she has not already ovulated, emergency contraception will prevent ovulation. If no egg is released, no pregnancy can occur. If she has already ovulated, emergency contraception will prevent implantation from occurring, usually by inducing bleeding so the lining of the uterus sheds.

Most emergency contraception is in the form of a pill or pills containing synthetic hormones. In some cases, the Copper T IUD can also be used as emergency contraception if it is inserted into the uterus within 5 days of unprotected intercourse. Some women elect to have the IUD removed after their next period after the danger of pregnancy has passed and some decide to leave it in and use it as their chosen method of birth control.

If a woman has any questions about using emergency contraception, she should consult with her health care provider.

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