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Is Plan B an abortion pill?

Medically reviewed by Kristianne Hannemann, PharmD. Last updated on Aug 20, 2024.

Official answer

by Drugs.com

No, Plan B is not an abortion pill. It is a type of emergency contraception that can prevent pregnancy from occurring. Plan B works best to lower the chance of becoming pregnant when it is taken as soon as possible, within 72 hours, after unprotected sex. The use of Plan B does not prevent 100% of pregnancies.

What is the difference between Plan B and abortion pills?

Plan B (levonorgestrel) and abortion pills are used in two different scenarios. Plan B is used to stop a pregnancy from happening, while abortion pills are used to end a pregnancy that has already occurred.

  • Plan B, also known as the morning-after pill, works by preventing the release of an egg from the ovary (ovulation) or by preventing fertilization. It does not work if pregnancy has already occurred.
  • Abortion pills, such as mifepristone and misoprostol, cause an abortion. They work by ending a pregnancy that has already been established in the uterus. Mifepristone blocks hormones required for a pregnancy to continue, while misoprostol causes the uterus to contract and empty.

While both Plan B and the abortion pill contain hormones, they have different mechanisms of action and serve distinct purposes.

What does Plan B do?

Plan B contains the hormone levonorgestrel, which is a progestin. It comes as a tablet that is taken by mouth within 72 hours after unprotected sex to help lower the risk of becoming pregnant. Plan B works by blocking the surge of luteinizing hormone, which usually happens before ovulation occurs (when your ovary releases an egg). This delays or stops ovulation. Additionally, Plan B thickens cervical mucus, which interferes with how well sperm can move and reach the released eggs. These actions help prevent fertilization of an egg so that pregnancy cannot occur.

Does Plan B work if the egg is already fertilized?

No. Plan B will not work if you are already pregnant (when a fertilized egg has attached to the lining of your uterus). Plan B temporarily stops ovulation, so that sperm cannot fertilize the egg. If you have already ovulated, Plan B will not work to prevent pregnancy. It also does not increase the risk of having a miscarriage, nor does it affect your ability to get pregnant in the future.

This is not all the information you need to know about Plan B (levonorgestrel) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

References

National Library of Medicine. July 2022. Levonorgestrel (Plan B One-Step®). In: Mother To Baby | Fact Sheets [Internet]. Accessed on August 20, 2024 at https://www.ncbi.nlm.nih.gov/books/NBK583410/

Plan B One-Step [package insert]. Updated January 2023. Foundation Consumer Healthcare LLC. Accessed on August 20, 2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6ce6b40e-14ac-47bd-a648-ddf9e452e559

Planned Parenthood Federation of America. Updated April 2016. The Difference Between the
Morning-After Pill and the Abortion Pill. Accessed on August 20, 2024 at https://www.plannedparenthood.org/files/3914/6012/8466/Difference_Between_the_Morning-After_Pill_and_the_Abortion_Pill.pdf

The American College of Obstetricians and Gynecologists. January 2023. What is the difference between abortion pills and morning-after pills? Accessed on August 20, 2024 at https://www.acog.org/womens-health/experts-and-stories/ask-acog/what-is-the-difference-between-abortion-pills-and-morning-after-pills

Vrettakos, C., et. al. May 2023. Levonorgestrel. In: StatPearls [Internet]. Accessed on August 20, 2024 at https://www.ncbi.nlm.nih.gov/books/NBK539737/

Read next

Can Plan B make your period late or cause bleeding?

Yes, Plan B (levonorgestrel) may lead to a delayed period or induce bleeding outside the typical menstrual cycle, as it contains a synthetic hormone. In order to prevent pregnancy, Plan B, similar to other contraceptive pills, needs to modify your hormonal levels, which can result in these menstrual alterations. It's worth noting that Plan B is linked to a higher likelihood of menstrual changes compared to regular birth control pills, due to its increased dosage. Continue reading

What are the signs that Plan B didn't work?

If you have had to take Plan B as an emergency contraceptive, you may be wondering if it has worked. While research shows it has an efficacy rate of 89% when used correctly, how easy is it to tell if it has worked for you? The easiest way to know that it hasn’t worked are a missed period and a positive pregnancy test. Continue reading

Does Plan B One Step work during ovulation?

No, Plan B One Step won’t work if you have already started ovulating because it works by temporarily stopping ovulation (when your ovary releases an egg for fertilization from sperm). Continue reading

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