Can Plan B Actually Make You Infertile? Experts Weigh In

Maybe it was a night of passion — or just a quickie in your closet. But if you got swept up in the moment, you might have forgotten to take your pill, or your “pull and pray” might not have been executed in a timely fashion. So if you want to prevent pregnancy, you’re going to need a Plan B. But can Plan B make you infertile?

What Is Plan B?

Plan B is an alternative when pregnancy wasn’t in your plans. “Plan B is an over-the-counter medication that can be taken after unprotected sex to prevent pregnancy,” Dr. Jenna McCarthy, MD, a board-certified reproductive endocrinologist and medical director with WINFertility tells Romper. “The active ingredient in Plan B is a high dose of progesterone, which is also the active ingredient in a birth control pill.” It’s best to take Plan B within three days of unprotected sex, Planned Parenthood reported, and it can decrease your chances of getting pregnant by 75-89%.

Here’s How Plan B Works

Before you start worrying about being infertile, you need to know how Plan B works in the first place. Its main goal: to prevent ovulation from occurring, Dr. Kecia Gaither, MD, MPH, FACOG, double board-certified in OB/GYN and Maternal Fetal Medicine, Director of Perinatal Services at NYC Health + Hospitals/Lincoln explains to Romper. “Plan B has a hormone called Levonorgestrel, which is a form of estrogen,” says Dr.Gaither. “This helps to prevent pregnancy.”

But how? “Plan B prevents an egg from being released,” adds Dr. McCarthy. “If there is no egg released, there is no way for a woman to get pregnant.” Specifically, levonorgestrel works by preventing the brain from sending out the hormone surge that causes you to ovulate. So when the sperm have nowhere to go (and no egg to fertilize), they die off.

Still, timing is everything when it comes to when you pop the pill. “Plan B needs to be taken within 72 hours of unprotected sex,” advises Dr. McCarthy, but you should definitely try to take it sooner rather than later. According to a study, researchers found that oral emergency contraception (which is what Plan B is), is most effective during the first 24 hours, and decreases in efficacy after that. Dr. McCarthy agrees, adding: “It is not 100% effective, but 7/8 women who take Plan B will not get pregnant.”

But Can Plan B Make You Infertile?

Although Plan B blocks an egg from releasing, it doesn’t mess up your fertility forever. Think of it more like a pause on potentially getting pregnant. “Plan B does not cause infertility,” says Dr. McCarthy. “The hormone in Plan B is very short-acting.” And that’s what’s important to remember: Plan B is a temporary birth control solution. “It’s a one-time pill, so it should not be used as a routine method of birth control,” says Dr. Gaither.

Overall, Plan B is a good option if you were otherwise occupied having orgasms or had a birth control breakdown. Since it’s not meant to be your primary form of BC, though, you should speak to your OB/GYN about more effective options, like birth control pills, an IUD, etc. But for the times when you’ve had an oops, Plan B can become your Plan A.

Study cited:

“Emergency contraception” 2003.

Experts:

Dr. Jenna McCarthy, MD, a board-certified reproductive endocrinologist and medical director with WINFertility

Dr. Kecia Gaither, MD, MPH, FACOG, double board-certified in OB/GYN and Maternal Fetal Medicine, Director of Perinatal Services at NYC Health + Hospitals/Lincoln