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In the aftermath of the Supreme Court ruling on Roe vs. Wade—leaving the legality of abortions up to individual states to decide—there has been a flurry of confusion over the legal status of different medications related to reproductive health, and how those drugs actually work. One such medication is Plan B.

Plan B is not the same as the abortion pill, and the two medications do not have the same result, but that has not stopped confusion around this medication’s mechanisms. In fact, in the wake of the Roe vs. Wade ruling, retailers including Amazon have put limits on the quantity of Plan B that can be purchased at one time as demand for the drug surged.

Due to the amount of information around the abortion pill and Plan B in the media, it’s important to know the differences between these two medications—and how to obtain them if needed.

Plan B One-Step is a form of emergency contraception (also known as postcoital contraception) taken after a person has engaged in sexual intercourse. Sometimes called the “morning after pill,” it’s used to prevent pregnancy after an unprotected sexual encounter or a failure of your chosen method of birth control. This can mean missed doses of your regular birth control pills, a broken condom or a failure to use any type of contraception.

“Plan B is one of a number of brands of ‘emergency contraception’ that can be taken within 72 hours of unprotected sex,” explains Suzanne Gilberg-Lenz, M.D., an OB-GYN and author of the upcoming book Menopause Bootcamp. 

While this type of medication was first mentioned in medical literature in the 1960s, it wasn’t until 1998 that the U.S. Food and Drug Administration (FDA) first approved a product designed for emergency contraception.

Today, there are several types of emergency contraceptive pills, ranging from over-the-counter progestin-only pills to selective progesterone receptor modulators available only through a prescription.

Emergency contraception works primarily by either preventing or delaying the ovulation process (the release of an egg from the ovary). Less common—but still possible—is emergency contraception that prevents fertilization of the egg by sperm if ovulation has already occurred.

Specifically, Plan B works by delaying ovulation, which means sperm cannot interact with an egg. If there is no interaction between sperm and egg, fertilization cannot occur. Plan B contains levonorgestrel, the same ingredient found in many birth control pills.

Other emergency contraception brands that contain levonorgestrel include Take Action and My Way, among others.

It’s important to know that if implantation of the fertilized egg has already happened and you are pregnant, emergency contraception won’t end or harm the pregnancy.

Another important caveat is that Plan B may not be as effective in individuals weighing over 165 pounds, according to Planned Parenthood. In this case, another type of emergency contraception worth considering is ella, which contains ulipristal acetate. This medication is available by prescription only, but it can be taken 120 hours (or five days) after unprotected sex. However, if you weigh over 195 pounds, this form of emergency contraception may not work as well.

The sooner you can take either type of emergency contraceptive pill after unprotected penetrative sex, the more effective the medication is likely to be, explains Dr. Gilberg-Lenz.

Failure rates for emergency contraception range from about 4% if taken three days after unprotected sex and rise to 10% if taken five days after, according to a study in American Family Physician[1]Weismiller D. Emergency Contraception. Am Fam Physician. 2004;70(4):707-714. . 

Taking emergency contraception will not impact your ability to get pregnant in the future.

Dr. Gilberg-Lenz cautions that emergency contraception isn’t nearly as effective as regular contraception, and that it does have side effects. “Side effects can last one to two days and are generally mild,” she adds. “Nausea, dizziness, cramping, fatigue or headaches may occur.”

For Plan B specifically, the company notes the following possible side effects:

After using emergency contraception, a menstrual period should occur within a week of when it normally would, according to the American College of Obstetricians and Gynecologists (ACOG). Some patients may experience irregular bleeding in the week or month following use of emergency contraception.

Dr. Gilberg-Lenz recommends taking a pregnancy test one to two weeks following the administration of emergency contraception to make sure there is no possibility of pregnancy.

Find the most popular at-home pregnancy tests on Amazon

The abortion pill is used to induce a medication abortion, also referred to as a medical abortion. Unlike emergency contraeption, which prevents a pregnancy from occuring in the first place, the abortion pill ends an existing pregnancy.

There are actually two medications involved in a medical abortion: mifepristone and misoprostol, both of which are approved by the U.S. Food and Drug Administration (FDA).

Mifepristone is the actual pill that disrupts hormone production and ends the pregnancy, explains Dr. Gilberg-Lenz. Then, misoprostol is administered 48 hours later to expel the products of conception.

You may be able to receive this medication up to 77 days (11 weeks) after the first day of your last period, depending on where you live, notes Planned Parenthood. Dr. Gilberg-Lenz stresses that the earlier the medications are administered, the more effective they are: “Efficacy is up to [nearly] 99% but depends on how far along the pregnancy is at the time of medication administration.” The dosing regimen and route of administration of the misoprostol may also slightly influence efficacy, she adds.

The Guttmacher Institute reports that in 2020, medication abortion accounted for 54% of U.S. abortions[2]Medication Abortion Now Accounts for More Than Half of All US Abortions. Guttmacher Institute. Accessed 7/18/2022. .

Side effects for a medication abortion may include the following:

Planned Parenthood recommends you call your doctor if you don’t have any bleeding after taking the second medication (misoprostol) or if you have a fever the day after you take misoprostol.

You do not need a prescription to obtain Plan B, and there are no age restrictions on the medication. The company notes that Plan B is regulated by the FDA—and is not connected to the recent Supreme Court ruling—and is therefore not impacted by any state abortion bans or restrictions. Plan B is available in retailers and drugstores nationwide, as well as online retailers like Amazon.

“At this time, most emergency contraception pills are available over the counter (except Ella) although we’re now hearing reports of local pharmacists refusing to dispense medications, especially in abortion restricted/forced birth locations,” explains Dr. Gilberg-Lenz.

In terms of medication abortions, in mid-July of 2022, President Joe Biden signed an executive order to protect access to FDA-approved abortion medication.

Even with this executive order, the future of the abortion pill access remains murky. Just like access to abortion more broadly, access to medication abortion pills depends on where you live and there may be more changes to come. Currently, the Guttmacher Institute reports that 29 states require the clinicians who administer the medications to be physicians, two states prohibit the use of the medication at a certain point in pregnancy and 19 states require the clinician providing the medication to be physically present.

“It is imperative to note that these medications are well-studied, safe, legal, effective and life-saving,” says Dr. Gilberg-Lenz.

The expert-recommended online resource Plan C offers information on at-home abortion pill access specific to where you live.

If you or someone you know has questions around taking Plan B or the abortion pill, talk with your health care provider or OB-GYN. They can help you determine which option is appropriate for you.

Zocdoc helps you find and book top-rated doctors, on demand. Visit them in their offices, or video chat with them from home. Check out the obstetricians and gynecologists in your area.

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Valerie is a seasoned writer and editor who has spent her career creating content in the parenting and women's wellness spaces. Before joining Forbes Health, Valerie was the trending news editor at Scary Mommy. When she's not helping women and families live their best and healthiest lives, she's spending time with her family, walking her dogs, reading or exercising.

Known professionally as “Dr. Lady Doctor,” Dr. Culwell is a fellowship-trained OB-GYN who has specialized in women’s reproductive health for over 20 years. She has served as a medical officer for the World Health Organization in Geneva, Switzerland and as senior medical advisor for the International Planned Parenthood Federation in London. Dr. Culwell currently serves as the senior vice president and chief medical officer at Afaxys, Inc. She maintains an active medical license and continues to regularly see patients in need of outpatient gynecologic care.