Frequently Asked Questions

Everything you need to know in one place

You want answers. We made it easy and put them all in one place.

The basics of Plan B

What is Plan B?

Plan B is a progestin‑only emergency contraception product that helps prevent pregnancy when taken within 72 hours of unprotected sex. It contains levonorgestrel 1.5 mg, the same active ingredient as regular birth control pills—just at a single, higher dose, and works by delaying ovulation.

Plan B is a backup method of preventing pregnancy and should not be used as regular birth control. Use as directed.

How effective is Plan B?

If you take Plan B as directed, it can significantly decrease the chance that you will get pregnant. About 7 out of every 8 women who could have gotten pregnant will not become pregnant after taking Plan B.

How does Plan B work?

Plan B helps prevent pregnancy by delaying ovulation. That is, it works by stopping the release of an egg from the ovary.

Will Plan B affect my fertility?

Plan B will not impact your future or long‑term fertility.

What happens if I’m already pregnant and I take Plan B?

Plan B is not an abortion pill and it will not affect an existing pregnancy. If you have any questions, please be sure to talk to your healthcare professional.

Can I take Plan B as my regular birth control method?

Plan B emergency contraception should not be taken as regular birth control—it’s a backup method to be taken if you have unprotected sex.

How long after taking Plan B can I resume my regular birth control?

Right away. Plan B does not impact the effectiveness of any regular birth control methods, so you can resume your regular birth control or start one, if you don’t have a regular method.

What should I do if I have questions about Plan B?

If you have questions or need more information about Plan B, fill out the Contact Us Form here, visit other pages on this website, or ask a healthcare professional.

Taking Plan B

When should I use Plan B?

Plan B is emergency contraception you can take when:

  • You didn’t use any form of birth control or had unprotected sex
  • There was an issue with your regular birth control method (eg, the condom broke or slipped)
  • You missed a dose (or more) of your regular birth control pill

Use the countdown calculator

How soon after unprotected sex should I take Plan B?

Plan B helps prevent pregnancy before it starts when taken within 72 hours of unprotected sex. The sooner you take it, the better it works.

How do I take Plan B?

Plan B One‑Step® is a single pill you take by mouth. It must be taken within 72 hours (3 days) after unprotected sex or to help prevent pregnancy. The sooner you take it, the better it works.

Can I take Plan B if I’m breastfeeding?

Yes, you can use Plan B when you are breastfeeding. In general, no harmful effects of progestin‑only pills, like Plan B One‑Step®, have been found on breastfeeding performance or on the health, growth, or development of the infant. However, random cases of decreased (less) milk production in mothers have been reported.

How often can I take Plan B?

Plan B emergency contraception should not be used as a regular method of birth control. However, if you have already used Plan B, it can be safely used again after another instance of unprotected sex or birth control failure. But again, Plan B should only be taken when your primary, regular birth control method was missed or your birth control method failed.

Will Plan B protect against future pregnancies?

Plan B doesn’t provide long‑term protection against future pregnancy—when taken as directed it works to help prevent pregnancy after only one incident of unprotected sex. If you are sexually active, even occasionally, see your healthcare professional or visit a family planning center/clinic to find a regular method of birth control that suits you.

Find a Family Planning Clinic

When is it not appropriate to use Plan B?

Do not take Plan B:

  • If you’re already pregnant, because it won’t work
  • If you’re allergic to levonorgestrel or any of the ingredients in Plan B
  • In place of regular birth control
  • If you’re male

This product is not intended for use in postmenopausal women.

Use before the first menstrual period is not appropriate.

What are the possible side effects of Plan B?

When used as directed, Plan B is safe and effective. It contains levonorgestrel—the same active ingredient as many popular birth control pills—just at a single, higher dose.

Some women may experience side effects, including:

  • a period that’s lighter, heavier, early, or late
  • nausea
  • lower abdominal cramps
  • tiredness
  • headache
  • dizziness
  • breast tenderness
  • vomiting

Some women taking Plan B may have changes in their period, such as spotting or bleeding before their next period. If your period is more than a week late, it’s possible you might be pregnant. Get a pregnancy test and follow up with your healthcare professional.

If you vomit within 2 hours of taking the medication, talk to your healthcare professional to find out if you should repeat the dose.

Do certain medications affect how well Plan B works?

Examples of drugs or herbal products that could decrease the effectiveness of Plan B include barbiturates, bosentan, carbamazepine, felbamate, griseofulvin, oxcarbazepine, phenytoin, rifampin, St. John’s wort, topiramate, and certain HIV/AIDS medications.

Contact your healthcare professional before taking Plan B if you have any concerns or are taking any of these medications.

Getting Plan B

Do I need a prescription to get Plan B?

No. Plan B is available right off the shelf at major retail stores—no prescription or ID needed. There’s also no age requirement—anyone can buy it.

Where can I buy Plan B?

Plan B can be found in the family planning aisle of all major retailers, including Target, Walmart, Walgreens, CVS, and Rite Aid. It’s also available at smaller pharmacies and some food stores around the country. Click here to find a store near you.

Is there any way to save on Plan B?

Cost shouldn’t hold you back from getting emergency contraception. That’s why there are two ways to save on Plan B: a coupon and a mobile rebate. Click here for how to save.

How do I talk to my partner about getting Plan B?

Not sure how to bring up the topic of taking Plan B? Try the tips below.

  • Start with the facts. This site is full of information to help you have a conversation about Plan B—whether it’s with a friend, family member, or partner.
  • Plan ahead. Consider making a list of what you want to discuss and try practicing the conversation out loud. Think about potential responses to any concerns your friend/family member/partner might have.
  • Find the right time and place. Make sure you have a private place to discuss Plan B—a place where you won’t get interrupted or feel rushed.
  • Be respectful. Respect what the other person is thinking and feeling. Be open to other opinions, but remember: it’s your body and your choice.
  • Practice safe sex. Discuss future contraception. Safe sex is important, even if you’re in a monogamous relationship (remember: neither birth control pills nor emergency contraception like Plan B protect against STDs or HIV/AIDS).
What other resources can I turn to for information about Plan B and emergency contraception?

Check out the websites below to stay informed on what’s happening in women’s healthcare, and to learn more about birth control options and emergency contraception.

Planned Parenthood

Emergency Contraception Website (Princeton)

Mayo Clinic

Henry J. Kaiser Family Foundation

National Family Planning & Reproductive Health Association

Find a Family Planning Clinic

Foundation Consumer Healthcare is not responsible for the content on the websites listed above and disclaims any liability for the content of any page or site listed above. Although the information above may be useful, it shouldn’t replace the advice of your healthcare professional. For questions about birth control and other women’s health issues, please talk to your healthcare professional.