Emergency Contraceptive Pill - Sexual Health Peer Resource Center

What it is: The easiest way to understand is to think of it as a larger dose of the birth control pill taken after unprotected intercourse to prevent pregnancy. Two common brands of are Plan B (offered at Vaden) and Preven.

When to use it: The “morning after pill” seems to imply that should be taken the morning after unprotected sex; however, can be taken any time within the first 72 hours after unprotected sex. The sooner it is taken, the better it will work to prevent pregnancy. Though it has not been formally tested, it is biologically implausible that the efficacy would plummet to zero after 72 hours. Taking ECPs on day 4 or even day 5 after unprotected intercourse will do no harm and may reduce the risk of pregnancy.

Effectiveness: On average, if 100 women have unprotected intercourse once during the second or third week of their cycle, 8 will become pregnant. Following treatment with progestin-only ECPs (such as Plan B), 1 will become pregnant (an 89% reduction in the risk of pregnancy. Combined ECPs (such as Preven) are slightly less effective reducing risk by 75%. If a woman used only (perfect use) as her method of contraception for a year, her annual risk of pregnancy would be about 38% with Preven and 19% with Plan B. ECPs when used correctly are not as effective as properly used methods of ongoing contraception.

How it works: Depending on when in the menstrual cycle they are taken, ECPs may inhibit or delay ovulation, inhibit tubal transport of the egg or sperm, interfere with fertilization, or alter the lining of the uterus, thereby inhibiting the implantation of a fertilized egg. The first pill is taken as soon as possible following unprotected sex. Another pill is taken twelve hours later.

Side Effects: Almost all women can safely use ECPs. The only absolute contraindication to use of ECPs is confirmed pregnancy, simply because ECPs will not work if a woman is pregnant. There are no long term side effects from using ECPs. About 23% of women taking progestin-only ECPs experience nausea and 6% vomit. Other side effects include fatigue, headache, dizziness, and breast tenderness. An anti-nausea drug is often prescribed along with , and if vomiting occurs within 1 hour after taking a dose, some clinicians recommend repeating that dose. Preven has higher side effects percentages: 50% nausea, 20% vomit.

Is abortion? No, use of emergency contraception does not cause an abortion. Emergency contraception prevents pregnancy. If a woman is already pregnant, emergency contraception has no effect, and is not harmful. Medical science defines the beginning of pregnancy as the implantation of a fertilized egg into the lining of a woman’s uterus. Implantation begins five to seven days after fertilization, and is completed several days later. [Source:


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	Choosing a Method Non-Methods Barrier Methods Hormonal Methods Chemical Methods Combination Methods Intrauterine Device Natural Family Planning Emergency Contraceptive Pill Fertility Charting Abstinence Sterilization	Emergency Contraceptive Pill What it is: The easiest way to understand is to think of it as a larger dose of the birth control pill taken after unprotected intercourse to prevent pregnancy. Two common brands of are Plan B (offered at Vaden) and Preven. When to use it: The “morning after pill” seems to imply that should be taken the morning after unprotected sex; however, can be taken any time within the first 72 hours after unprotected sex. The sooner it is taken, the better it will work to prevent pregnancy. Though it has not been formally tested, it is biologically implausible that the efficacy would plummet to zero after 72 hours. Taking ECPs on day 4 or even day 5 after unprotected intercourse will do no harm and may reduce the risk of pregnancy. Effectiveness: On average, if 100 women have unprotected intercourse once during the second or third week of their cycle, 8 will become pregnant. Following treatment with progestin-only ECPs (such as Plan B), 1 will become pregnant (an 89% reduction in the risk of pregnancy. Combined ECPs (such as Preven) are slightly less effective reducing risk by 75%. If a woman used only (perfect use) as her method of contraception for a year, her annual risk of pregnancy would be about 38% with Preven and 19% with Plan B. ECPs when used correctly are not as effective as properly used methods of ongoing contraception. How it works: Depending on when in the menstrual cycle they are taken, ECPs may inhibit or delay ovulation, inhibit tubal transport of the egg or sperm, interfere with fertilization, or alter the lining of the uterus, thereby inhibiting the implantation of a fertilized egg. The first pill is taken as soon as possible following unprotected sex. Another pill is taken twelve hours later. Side Effects: Almost all women can safely use ECPs. The only absolute contraindication to use of ECPs is confirmed pregnancy, simply because ECPs will not work if a woman is pregnant. There are no long term side effects from using ECPs. About 23% of women taking progestin-only ECPs experience nausea and 6% vomit. Other side effects include fatigue, headache, dizziness, and breast tenderness. An anti-nausea drug is often prescribed along with , and if vomiting occurs within 1 hour after taking a dose, some clinicians recommend repeating that dose. Preven has higher side effects percentages: 50% nausea, 20% vomit. Is abortion? No, use of emergency contraception does not cause an abortion. Emergency contraception prevents pregnancy. If a woman is already pregnant, emergency contraception has no effect, and is not harmful. Medical science defines the beginning of pregnancy as the implantation of a fertilized egg into the lining of a woman’s uterus. Implantation begins five to seven days after fertilization, and is completed several days later. [Source: