Frequently Asked Questions

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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.

How effective is Plan B?

If women take Plan B as directed, it can significantly decrease the chance that they 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 future fertility?

Plan B will not impact a woman’s future or long‑term fertility.

What happens if a woman is already pregnant and takes Plan B?

Plan B is not an abortion pill and it will not affect or harm an existing pregnancy. It works by stopping the release of an egg from the ovary.

How long after taking Plan B can women resume their regular birth control?

Right away. Plan B does not impact the effectiveness of any regular birth control methods, so women can resume their regular birth control or start one, if they 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, or visit other pages on this website.

Taking Plan B

When should women use Plan B?

Plan B is emergency contraception women can take when:

  • They didn’t use any form of birth control or had unprotected sex
  • There was an issue with their regular birth control method (eg, the condom broke or slipped)
  • They missed a dose (or more) of their regular birth control pill
How soon after unprotected sex should women take Plan B?

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

Can a woman take Plan B when breastfeeding?

Yes, women can use Plan B when they 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 the mother have been reported.

How often can women take Plan B?

Plan B emergency contraception should not be used as a regular method of birth control. However, if women have already used Plan B in their lifetime, 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 a woman’s primary, regular birth control method was missed or their 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 women are sexually active, even occasionally, they should see a healthcare professional or visit a family planning center/clinic to find a regular method of birth control that suits them.

When is it not appropriate to use Plan B?

Women should not take Plan B if:

  • They’re already pregnant, because it won’t work
  • They’re allergic to levonorgestrel or any of the ingredients in Plan B
  • In place of regular birth control
Does Plan B (or levonorgestrel EC) work for women with a BMI over 25 kg/m2?

We hold the same belief as the FDA, which states that there are no safety concerns that preclude the use of levonorgestrel emergency contraceptives in women generally, and we continue to believe that all women, regardless of how much they weigh, can use these products to prevent unintended pregnancy following unprotected sex or contraceptive failure. The most important factor affecting how well emergency contraception works is how quickly it is taken.

When emergency contraception is taken as directed within 72 hours after unprotected sex or birth control failure, it can significantly decrease the chance that a woman will get pregnant. In fact, the earlier the product is taken after unprotected intercourse, the better it works. Emergency contraception is not 100% effective, which is why it is critical that women have a “Plan A” (regular) birth control method or start one if they don’t have one.

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
Do certain medications affect how well Plan B works?

Some drugs or herbal products that may decrease the effectiveness of progestin‑only pills (such as Plan B) include: barbiturates, bosentan, carbamazepine, felbamate, griseofulvin, oxcarbazepine, phenytoin, rifampin, St. John’s wort, topiramate, and certain HIV/AIDS medications (such as protease inhibitors and non‑nucleoside reverse transcriptase inhibitors).

Getting Plan B

Is a prescription required 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 (of any gender!) can buy it.

Who can purchase Plan B One‑Step? Can a woman’s partner purchase Plan B for her?

Plan B One‑Step is available right off the shelf at all major retailers without a prescription, ID, age, or gender restriction.

Where can Plan B be purchased?

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

Where should I stock Plan B in my store?

Plan B should be kept on the shelf in the family planning, sexual health, or feminine hygiene section. Plan B has been available over the counter without an age restriction or a prescription or ID required for purchase since 2013.

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