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What to Do if You Took the Morning-After Pill, Then Had Unprotected Sex

If you’re not looking to have a baby anytime soon, using some form of birth control to protect yourself from unintended pregnancy should be pretty much non-negotiable. But accidents do happen, which is where emergency contraception comes into play.

Emergency contraception (EC, often called the morning-after pill) can help protect you from pregnancy if you had sex without birth control or if your birth control method failed. But there can be confusion surrounding the practicalities of using EC, like...what happens if you take the morning-after pill and then have unprotected sex? Does it offer preemptive protection so you don’t have to worry about pregnancy? Or do you have to take another dose of EC for maximum defense against getting pregnant unexpectedly? We talked to ob/gyns for the answer.

Here’s a quick primer on how the morning-after pill works.

The FDA has approved two types of pills for use specifically as emergency contraception: ulipristal acetate (Ella) and levonorgestrel (Plan B One-Step and various generic forms, according to the Mayo Clinic). Both are often referred to with the catchall term “morning-after pill.” (There are other forms of emergency contraception—the copper IUD and taking a large dose of combination birth control pills at once—but for the purposes of this discussion we’re going to focus on the drugs known as the morning-after pill.)

Ulipristal acetate and levonorgestrel both primarily work by preventing or delaying ovulation. If neither of your ovaries releases an egg, there’s nothing for sperm to fertilize. Or if ovulation is delayed long enough that there’s no longer any sperm in your system when you do release an egg, same result: You don’t get pregnant. These medications may also make your endometrial lining a less hospitable place for a fertilized egg to implant so that even if sperm does manage to fertilize an egg, it can’t receive nutrients to sustain a pregnancy. (The efficacy of these mechanisms may be lower for high-BMI people. You can read more about that here.)

But—we cannot stress this enough—if a fertilized egg has already implanted in your uterus, emergency contraception will not stop or harm the pregnancy. Although they’re sometimes conf

used for each other, emergency contraception is not the same thing as the abortion pill. Also known as a medical abortion, the abortion pill does actually terminate pregnancies. The morning-after pill does not.If you take the morning-after pill and then have unprotected sex, you’re cutting into the usual window of effectiveness.

“These medications work best when taken as soon as possible after unprotected intercourse,” Melissa Goist, M.D., an ob/gyn at the Ohio State University Wexner Medical Center, tells SELF.

Levonorgestrel-based emergency contraception like Plan B is most effective when you can take it within 72 hours after having unprotected sex, while ulipristal acetate (Ella) has the same efficacy for five days after you have unprotected sex, after which point its potency drops and it is not recommended.

The key word here is “after.” Taking emergency contraception before you have unprotected sex is not going to offer maximum protection going forward because sperm can live inside you for up to five days after ejaculation, Dr. Goist explains. Since these drugs only provide the most powerful protection for up to three to five days post-sex, having unprotected sex after taking EC basically means the sperm might outlast the medicine’s most effective window.

Here’s another way to think of it: Imagine having unprotected sex on Sunday, taking the morning-after pill on Monday at 8 a.m., then having unprotected sex again on Tuesday. You’ll be the most protected from Monday through Thursday at 8 a.m. if you take Plan B and other levonorgestrel-based EC, or Saturday at 8 a.m. if you take Ella. Any sperm from Tuesday’s intercourse, however, could theoretically live inside of you until Sunday—leaving you vulnerable to unintended pregnancy even though you technically took the morning-after pill. While you might still be protected, you’re leaving a lot up to chance, Lauren Streicher, M.D., a professor of clinical obstetrics and gynecology at Northwestern University Feinberg School of Medicine, tells SELF. “There’s no data to support that. It hasn’t been tested in clinical trials that way.”