Emergency contraception (EC), previously known as the "morning-after pill," is the term for hormone (birth control) pills taken within 5 days after unprotected intercourse to prevent pregnancy. EC can reduce your chance of getting pregnant by 75% to 90% if taken in the first 72 hours, and is somewhat less effective if taken 3-5 days after unprotected intercourse.
- EC can prevent pregnancy by temporarily delaying ovulation (the
release of eggs). It also may stop fertilization (the joining of
an egg and sperm), or stop implantation (the attachment of a fertilized
egg to the uterine wall).
- EC is not an abortion pill, and will not work if you already
- If your previous menstrual cycle was unusual, or if you suspect
that you may already be pregnant, a pregnancy test is advised prior
to taking EC. If your pregnancy test is negative, it is okay to
take EC. If your pregnancy test is positive, do not take EC. Call
the Clinic Nurse Advice Line at (510) 643-7197.
- EC should be taken as soon as possible within 5 days after unprotected
intercourse. There are several EC options, including multiple doses
of regular oral contraceptives. Follow instructions in the package,
or on the medication label.
- Your next menstrual period should begin within 2 to 3 weeks. Call
the Clinic Nurse if your period has not started within 3 weeks after
- Studies to date have not shown evidence of birth defects in humans
if EC fails and pregnancy occurs.
Possible symptoms or side-effects with emergency contraception:
- Nausea and occasionally vomiting: The risk of nausea is lower with progestin-only EC (such as Plan B).
Nausea is usually worse when
the stomach is empty. Try eating small amounts of food at frequent
intervals. For example, eat a cracker or light snack every 1 or
2 hours. If vomiting occurs within 1 to 2 hours after taking the
tablets, please call the clinic for advice. It is possible that
you may not have absorbed enough of the medication to protect you against
pregnancy. You may consider pre-treating for nausea with Dramamine®, Bonine®
(Meclizine Hydrochloride) or Benadryl® (Diphenhydramine). These
medications are available without a prescription. They may cause
- Breast tenderness: This may be uncomfortable but will go away when you start your period. A well-fitting bra and some ibuprofen or acetaminophen may be helpful.
- Emergency contraception is not intended to be used as a
substitute for regular contraception. It is not as effective as
regular birth control methods.
- Unprotected intercourse can result in sexually transmitted infections
(STIs). Schedule an appointment for an STI test 1 to 2 weeks after
- You should not take any EC containing estrogen if you have a blood-clotting disorder, active liver disease, current migraine headache, or a history of breast cancer. Though serious side effects such as blood clots have on rare occasions been associated with longer-term use of combined oral contraceptives, complications have not been reported with the use of EC.
UHS provides Plan B, a form of progestin-only emergency contraception. Plan B is available at the UHS Pharmacy without a prescription to women and men aged 18 and older, with a picture ID to verify age. The cost of over-the-counter Plan B is $30. If you are a woman under 18, you can get a prescription by calling the Advice Nurse at (510) 643-7197. If the Tang Center is closed, you may get EC over the counter at a local pharmacy instead. Consider obtaining EC in advance and keeping it at home, so that you will have some easily available in case of an emergency.
For more information about contraception and safer-sex guidelines, make an appointment with a trained sexual health peer educator or clinician, call the Advice Nurse, or drop by the Self-Care Resource Center.
- Appointments with a peer educator or clinician: (510) 642-2000
- Advice Nurse: (510) 643-7197
- Self-Care Resource Center: (510) 642-7202
- Pregnancy: Medical, Counseling and Educational Services
- Sexual Assault: Medical, Counseling and Educational Services
- Not-2-Late: The Emergency Contraception Website
The Office of Population Research at Princeton University
- Emergency Contraception FAQ
The National Women's Health Information Center
Disclaimer: The information provided here is not intended to diagnose, treat or provide a second opinion on any health problem or disease. It is meant to support, not replace, the relationship that exists between an individual and his/her clinician.
Last revised: March 2008