How many birth control pills can be taken after unprotected sex for emergency contraception?

Originally Published: May 1, 1994 - Last Updated / Reviewed On: August 21, 2012
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Dear Alice,

Is there any way for a woman to combine her birth control pills to get the same effect as PCC (post-coital contraception)? If so, what is the dosage? For example, could I take three or four or even all of my birth control pills at once in order to get the same effect? I need to know the answer: How many pills will equal one PCC dosage? Please tell me because otherwise I'm going to take the whole month's worth at once.

—Desperate

Dear Desperate,

"Post-coital contraception," "the morning after pill," and "emergency contraception" are all names given to hormonal medication that is taken after unprotected sex to prevent pregnancy. Some birth control pills that contain ethinyl estradiol and levonorgestrel are considered safe and effective for use as emergency contraception (EC). However, if a woman has been taking her birth control pills regularly and as directed by her health care provider, taking them in the higher emergency contraceptive dose isn't necessary to prevent pregnancy.

The number of birth control pills to be used as emergency contraception depends on how much of each hormone the pills have, which varies by brand. For more information, you can visit Planned Parenthood's Emergency Contraception website. Taking an entire pill-pack, however, isn't recommended since taking so many pills at once will likely cause vomiting. Since the effectiveness of these pills to prevent pregnancy depends on their being absorbed into the bloodstream, they won't work if they're thrown up.

Studies have shown that 100 micrograms (mcg) of ethinyl estradiol together with 0.5 milligrams of levonorgestrel taken in two doses 12 hours apart is approximately 75 percent successful at preventing pregnancy, if taken within 5 days (120 hours) of unprotected sex. The sooner after unprotected sex the pills are taken, the more effective they are at preventing pregnancy.

Emergency contraceptive pills, like regular birth control pills, prevent pregnancy by preventing ovulation, only they do so on a short-term basis (for the five or so days that sperm can live in the female reproductive tract). Side effects may include temporary nausea, but otherwise, the risks associated with taking emergency contraception are the same as those associated with birth control pills and are minimal.

Plan B, a brand of progestin-only emergency contraception, is 89 percent effective and has fewer side-effects than regular birth control pills taken as EC. Plan B is also now available without a prescription at US pharmacies for people 17 or older. Women under 17 still need a prescription to get Plan B in most states. For more information on the availability of Plan B, check out Where can I get the morning after pill? in Alice's archive.

If you're at Columbia and under 17, you can get a prescription for EC from a health care provider at Medical Services. Appointments are available online through Open Communicator or by calling x4-2284. When speaking with the receptionist, be sure to mention the reason for your call in order to secure the earliest appointment possible. After hours, a clinician-on-call is available at x4-9797. You may also want to talk with your health care provider about finding a form of birth control that fits your lifestyle.

For more details about EC, speak with your health care provider and/or call the Emergency Contraception Hotline at 1.888.NOT.2.LATE (668.2.5283).

Alice