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
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.
* * *