5 Things You Need to Know About Plan B

The morning-after pill is a good option for preventing unintended pregnancy, but it’s not your only one (and it may not be as effective as you think!)

Plan B may be kept behind the counter at the pharmacy, but it’s reached the cultural mainstream of late. In a recent episode of Inside Amy Schumer, the comedian used it as a punchline in her hilarious “Amy Schumer Doll” skit. (“Uh-oh, no wrapper on the floor. Time for Plan B!”)

Schumer’s joke suggests that Plan B is occasionally a Plan A—but in practice this is not a great idea, says Ashley Waddington, a contraception expert, OB-GYN and assistant professor of Obstetrics and Gynaecology at Queen’s University in Kingston, Ont. “I worry if people are using it that way that they [mistakenly] think it’s more effective than it is.”

A lack of understanding about the way Plan B works may also result in the very thing women are aiming for it to prevent: unintended pregnancy.

Here are five things you need to know about the morning-after pill right now.

CHICAGO, IL - APRIL 05:  This photo illustration shows a package of Plan B contraceptive on April 5, 2013 in Chicago, Illinois. A federal judge in New York City has ordered the Food and Drug Administration to make Plan B contraceptive, also known as the morning after pill, available to younger teens without a prescription within 30 days. The judge's ruling overturns a December 2011 decision by the FDA to restrict access to the contraceptive to any girl under 17 years of age.  (Photo Illustration by Scott Olson/Getty Images)

(Photo: Scott Olson/Getty Images)

1. How it works (and doesn’t)
Plan B is a hormone-based form of emergency contraception. Think of it like the birth control pill, only stronger. “It’s the same hormone that’s used in the pill essentially, but in a higher dose,” explains Waddington.

It works by pressing pause on ovulation, delaying the release of an egg from the ovary (if there’s no egg to be fertilized, then there’s no pregnancy). Contrary to popular belief, however, Plan B doesn’t generally stop a fertilized egg from attaching to the uterine wall. If the egg has left the chamber, so to speak, you’re playing Reproductive Roulette.

2. Timing is everything
Because it’s linked to ovulation, when you take Plan B is highly significant. “If you’ve already ovulated—if that egg has already left the ovary—it won’t do anything to interrupt the pregnancy,” says Waddington.

If you’re cycle-savvy then you’ll be able to gauge this window with some measure of accuracy, but if you’re not then it’s wiser to opt for more effective means of contraception during intercourse.

3. It’s not as effective as you think
Plan B—when used correctly and during the time in which its intended to be used—is still never going to be 100 percent effective. “Plan B would reduce your risk of pregnancy by about 75 percent, based on what your risk of pregnancy was on the day you had intercourse, so that obviously varies from one day to the next in the menstrual cycle,” says Waddington. She also emphasizes that it doesn’t protect against STIs.

“Condoms, condoms, condoms,” she says. “People should be using condoms consistently for STI protection and to improve their pregnancy prevention strategies.”

4. Regular use can mess up your cycle
While there don’t appear to be any detrimental long-term effects to using Plan B, regular to intermittent use can mess with your menstrual cycle in the short term.

Your periods will become less predictable, says Waddington, and you may experience more spotting and bleeding than usual. “Because of the way it delays ovulation, the body can never get back on track to a regular pattern.”

And if your period becomes less regular and predictable it makes taking Plan B dicier, as you won’t be entirely sure when you’re ovulating or about to ovulate, which—you guessed it—can result in an accidental pregnancy.

5. There’s a more reliable means of emergency contraception
Plan B may be easy enough to obtain, but Waddington says that the copper IUD—a non-hormonal form of emergency contraception that has to be inserted by a doctor—is preferable if you’re serious about preventing pregnancy. You can have it inserted up to five days after unprotected sex, she says, and it’s considered 99 percent effective in delaying pregnancy. There are other benefits, too. Once inserted, it can be used for up to five years. It’s also economical. Instead of the $40 Plan B one-time use, a copper IUD costs less than $100. (Hormonal IUDS are also an option but they’re pricier at $300–$400 for five-year protection.)

The takeaway? Plan B is a good option, but it isn’t your only one.