Student Health Services
Holloway Hall

Emergency Contraception Plan B Instructions & Fact Sheet

What is Plan B?

Plan B is a progestin only emergency contraceptive. It is made of the progestin called Levonorgestrel. It is intended for use to prevent unintended pregnancy, and should be used within 72 hours following unprotected intercourse or a known or suspected contraceptive failure (such as condom breakage). It is available over-the-counter to those aged 17 and over, and to those 16 and younger by prescription only. It is not intended for routine use as a contraceptive.

How effective is Plan B in preventing pregnancy?

Plan B is very effective in preventing pregnancy if used as directed within 72 hours of unprotected intercourse. In clinical trials, the expected pregnancy rate of 8% (with no contraceptive use) was reduced to approximately 1% with Plan B One-Step.

What are the side effects of Plan B?

The most common side effects include heavier menstrual bleeding (30.9%), nausea (13.7%), lower abdominal pain (13.3%), fatigue (13.3%), and headache (10.3%). If you vomit within two hours of taking the tablet, immediately contact your healthcare provider to discuss whether to take another tablet.

How does Plan B work?

Plan B works primarily by preventing ovulation or fertilization. It does this by altering transport of the ova and/or sperm in the fallopian tubes. Plan B may also inhibit implantation in the endometrium. Plan B will not disrupt the process of implantation once it has already begun.

How do I take Plan B?

For best efficacy, take the pill as soon as possible, within 72 hours of unprotected intercourse. Take the dose of Plan B with a meal to reduce the chance of nausea. If you are very prone to nausea, you may take Dramamine (over-the-counter) an hour before taking the pill.

Is Plan B safe?

The specific hormone in Plan B has been used in birth control pills for a long time, and has a very good safety profile. It is not effective in terminating an existing pregnancy. The only people who should not take Plan B are women who are already pregnant, are allergic to any of the components of Plan B (the hormone and the fillers), or have undiagnosed abnormal genital bleeding. It is not effective in preventing sexually transmitted diseases or HIV.

What will happen after I take Plan B?

Women who take Plan B should have their period within 3 weeks of taking it. You may have your period on time, a little early, or a little late. Your period may be lighter or heavier than usual. Make a follow up appointment at the Health Care Center if your period is delayed more than one week beyond the date you expected your period. If you develop severe lower abdominal pain 3 to 5 weeks after taking Plan B One-Step, you should make a follow up appointment to be evaluated for a possible ectopic (tubal) pregnancy.

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