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Whoops! Birth control you can use after sex

There are lots of reasons the best laid plans for using birth control don't work out...

by Sara Kennedy, MD, MPH

There are lots of reasons the best laid plans for using birth control don’t work out:

I completely forgot to take my pill (!)...

I just didn’t have enough money to pay for the ring this month...

The condom broke...

We’d had some drinks and got carried away...

Something like this happens to most of us at some point. If you’ve had unprotected sex for any reason, you can still prevent pregnancy by using emergency contraception (EC). Some types of EC are also called “the morning after pill,” and all EC prevents pregnancy after sex.

How does it work, and how well?

There are two forms of EC: pills and the copper-T intrauterine device (IUD). All methods of EC available on the US market are safe and most have been used by women for more than 30 years. EC methods differ in terms of effectiveness and side effects.

EC Pills

EC pills work by preventing or delaying ovulation and preventing sperm from fertilizing the egg. You can use EC right away or up to five days after sex. The sooner you use it, the better it works. The EC pills currently on the market in the U.S.—all made with the hormone levonorgestrel—are:

  • Plan B One-Step—as the name suggests, it’s a single pill taken once.
  • Plan B / Next Choice—Next Choice is the generic version of Plan B. Both are taken as two pills, 12 hours apart.

If you take EC pills within 24 hours after sex, they reduce your risk of pregnancy by up to 95%. Overall, they are 89% effective, meaning they prevent about 7 of 8 pregnancies that normally would have occurred.

There are several side effects that you may experience when using an EC pill. Some women get a headache, feel nauseous or throw up. Some women feel tired, have mild abdominal pain, or irregular bleeding. These side effects clear up after one or two days. Your next period may start earlier or later than normal, or be heavier or lighter than normal. Most women will have their period within a week of taking EC pills.**

The newest EC pill: ella

The Food and Drug Administration just approved a new EC pill called ella. It contains a different type of drug called an anti-progestin (ulipristal acetate). Ella has been available in Europe for several years, and should be available in the U.S. in the next year. [Editor update: ella was released a few months after this article was written and is now available in the states.] It will be more expensive than other EC pills, and you will need a prescription to get ella, no matter how old you are. Studies show that ella is safe and more effective than other types of EC pills at preventing pregnancy when used up to 5 days after unprotected intercourse.

The copper-T IUD as EC

The copper-T is a small, flexible intrauterine device (IUD) that can be inserted up to 5 days after unprotected sex to prevent pregnancy. When you use the IUD as EC, it works by preventing sperm from fertilizing the egg or by preventing the egg from implanting in the uterus. It is much more effective than EC pills; it reduces your risk of getting pregnant by over 99%. If you would like a hassle-free, highly effective method of birth control for the longer term, the copper-T could be a good choice for EC.

Looking for EC now?

EC pills are available over-the-counter in the U.S. to anyone 17 years and older. Not all pharmacies carry EC pills, so you may want to call ahead to check, or use our EC search tool. EC pills are kept behind the counter, so you will have to ask the pharmacist and show proof of your age. Depending on where you live and what health coverage you have, EC pills range in price from free to $45.

EC pills are safe for younger women to use, but in most states women under 17 need a prescription to get them. In some states, pharmacists can prescribe EC to women of any age without a clinic visit. (As of this writing, these states include Alaska, California, Hawaii, Maine, Massachusetts, New Hampshire, New Mexico, Vermont, and Washington.)

If you’d like to use a copper-T IUD for EC, it must be inserted by a nurse or doctor. The price depends on where you live and what health coverage you have. Talk to someone at your local clinic or your doctor for more information.

Next time...

EC pills aren’t recommended for repeated use because they’re not as effective as other birth control methods and they can be expensive. If you go to your local clinic or doctor for EC pills, talk to them about other affordable, manageable birth control methods.

**Note: If you have packets of the Pill, you may be able to use regular birth control pills as EC. Read "The Yuzpe method: Effective emergency contraception dating back to the ‘70s" to learn more.

Sara Kennedy, MD, MPH, is an Obstetrician/Gynecologist and a clinical fellow in Family Planning at the University of California, San Francisco (UCSF). Originally from Pennsylvania, Sara has studied and lived around the world, including a residency at Northwestern University in Chicago and a master’s degree in Australia, where she met her husband! Sara is passionate about women's health, particularly helping women in vulnerable situations obtain the knowledge and resources they need in order to control their reproductive health.

Dr. Kennedy is a faculty member at UCSF. However, the views and opinions expressed herein do not necessarily state or reflect those of the Regents of the University of California, UCSF, UCSF Medical Center, or any entities or units thereof.

Hi Sarah, Thanks for your question. It's difficult to say what your risk for pregnancy might be based on what you wrote. It depends on whether you were already using a method of birth control before starting the shot and when your last period started. For more information, check out this fact sheet:

2014-01-08 02:31:46 UTC

Sara Kennedy

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