Key takeaways:
Plan B One-Step (levonorgestrel) is an emergency contraception pill that’s available over-the-counter (OTC).
Plan B is not an abortion pill, and it won’t stop a pregnancy that’s already started. It works by preventing your body from releasing an egg.
Plan B can cause some mild side effects, such as nausea and changes to your next period. But when taken as directed, it’s about 87% effective at preventing pregnancy.
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When it comes to emergency contraception, there’s often a lot of confusion and misinformation surrounding it. One common mix-up is that people think emergency contraception is a form of abortion. This can make some people hesitate when deciding if they can or should take a medication like Plan B One-Step (levonorgestrel).
Well, we’re here to clear things up. Plan B is not an abortion pill. Neither are any other emergency contraceptives. These pills and the copper IUD (Paragard) can help prevent a pregnancy if you take it shortly after you’ve had unprotected sex. They are a form of birth control.
Read on below to learn about how Plan B works and how it’s different from abortion pills.
How does Plan B work?
Plan B is a single-dose emergency contraceptive pill that contains the hormone levonorgestrel. Levonorgestrel is a progestin, a lab-made form of progesterone (a sex hormone). Plan B is available over-the-counter (OTC), so you don’t need a prescription.
When you take Plan B, it delays ovulation (the release of an egg) for a few days. This means there’s no egg available for sperm to fertilize. And no fertilized egg means no pregnancy.
Plan B is also thought to thicken the mucus made by your cervix. This can make it harder for sperm to swim and reach an egg.
Does Plan B work with birth control?
Yes. If you already use other birth control, you can take Plan B. This medication doesn’t interfere with how other birth controls work — and vice versa. So you can continue or start another birth control method without regard to when you took Plan B.
Is taking Plan B the same as having an abortion? What’s the difference?
No. Plan B is not an abortion pill. It won’t stop a pregnancy that’s already started. While the manufacturer of Plan B lists pregnancy as a contraindication (a reason you shouldn’t take a medication), research hasn’t found that this medication harms an unborn baby. The reason the manufacturer lists pregnancy as a reason not to take Plan B is because it won’t work to stop a pregnancy.
Abortion pills, such as mifepristone (Mifeprex) and misoprostol (Cytotec), work very differently from Plan B. Mifepristone blocks your body’s natural progesterone, which is needed to start and maintain a pregnancy. Misoprostol causes your cervix to open and your uterus to contract, helping you to push tissue out. Taking these pills can effectively stop a pregnancy during the first 10 weeks.
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What are the side effects of Plan B?
Plan B’s side effects are generally mild and go away quickly. The most common side effect is a heavier period the next time it comes around.
Other common side effects include:
It’s also possible that your next period will be later than usual. Usually, your period should still start within a week of when it normally would. If your period is more than 7 days late, you should take a home pregnancy test.
What are the dangers of the morning after pill?
Very rarely, women who have taken Plan B have experienced an ectopic pregnancy. This is a pregnancy that starts outside of the uterus. It can be life-threatening and needs immediate medical attention. Contraceptives that only include a progestin, including Plan B, slightly raise the risk of this complication.
If you notice severe pelvic pain and unusual vaginal bleeding during the weeks that follow taking Plan B, contact your healthcare provider. If you do become pregnant after taking Plan B, it’s important to let your healthcare provider know that you took it. They may want to check to make sure you’re not experiencing an ectopic pregnancy.
How effective is the Plan B pill?
Plan B is quite effective, but not as effective as routine birth control. Plan B should be taken within 72 hours (3 days) of unprotected sex. But it’s more effective the quicker you take it. When taken within this timeframe, it’s about 87% effective.
There is some concern that Plan B is less effective for women with larger bodies. Studies have found that Plan B’s effectiveness may drop if you weigh more than 165 pounds. But it’s not a reason to avoid using Plan B, especially if it’s the only emergency contraception available to you.
The most important factor when it comes to Plan B being effective is time. Taking it as soon as you can after sex is how you can give Plan B the best chance to work.
Which should you take: Plan B or an aborton pill?
If you recently had unprotected sex and don’t want to become pregnant, Plan B or one of its generic versions (like Next Choice One Dose or Aftera) may be an option you want to consider. Remember, the goal of these medications is to prevent pregnancy. They’re a form of birth control you can use after sex.
If you’ve recently found out you’re pregnant and you’re not sure it’s something you want, talk to your healthcare provider. You can discuss together whether abortion pills (also called a medication abortion) are an option for you, as they’re not right for everyone. Whether you can use them depends on how far along your pregnancy is. If you and your healthcare provider decide abortion pills aren’t the right choice, there are other abortion options available.
The bottom line
Plan B is an OTC emergency contraception pill. It’s not a form of abortion and won’t stop a pregnancy that’s already started. Plan B should be taken within 3 days of unprotected sex. Side effects are usually mild for most women, and might include nausea and changes to your period.
If you're already pregnant, Plan B isn’t the right choice for you. Discuss your options with your healthcare provider to see which choice would be best for you.
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References
DailyMed. (2013). Label: Levonorgestrel tablet.
Foundation Consumer Healthcare. (n.d.). Frequently asked questions.
MedlinePlus. (2016). Levonorgestrel.
Vrettakos, C., et al. (2021). Levonorgestrel. StatPearls.
You and Your Hormones. (2021). Progesterone. Society for Endocrinology.















