No matter how good you are at tracking your periods, being conscious of your fertile windows, and educating yourself on all methods of protection, sometimes things happen. “And that includes sex happening when you didn’t plan it,” says Kate White, MD, MPH, assistant professor of obstetrics and gynecology at Boston University. “Which is why everyone has to have a plan B around birth control, whether that’s the real Plan B or something else.”
If you never thought emergency contraception was a topic you’d need to know about, think again: White says she firmly believes it’s a preventive tool any sexually active, heterosexual woman who doesn’t have an implant or IUD should have on hand in her medicine cabinet. “Emergency contraception is like a box of bandages,” she says. “You don’t buy bandages when you cut your finger; you buy them in advance so you have them when you need them.”
And while White encounters many common misconceptions around emergency contraception, she’s eager to dispel one: There’s absolutely no harm in using it whenever you need to, even if it’s your main form of birth control.
“Taking steps to prevent a pregnancy you don’t want is a really responsible act, and for some women who may have sex really infrequently—maybe their partner doesn’t live in the same city as them or they don’t have a regular partner, etc.—taking emergency contraception may be the best option for them. Taking [the pills] back to back will probably throw off your period to a certain degree, which will make it a little harder to predict when your next period is coming, but it doesn’t do any lasting damage.”
Ready to dig into the details on emergency contraception? Here are your options:
1. Emergency contraceptive pills (also called “morning-after pills”)
There are a few different types of morning-after pills, but in the United States, there are two options: Plan B and Ella. Plan B (also called Next Choice) is available over the counter without a prescription in the U.S., which makes it a more common choice.
The morning-after pills work by preventing ovulation, but they won’t be effective if you’ve already ovulated (which you may not know). Plan B is most effective if taken in the first 12 hours after sex, but it does retain some effectiveness for up to 120 hours (five days) after sex. Ella remains effective at the same level for all five days, but does require a prescription.
While Plan B is easier to get at any time, it does has a significant limitation you may not know about. “The downside is that Plan B starts to lose effectiveness if you’re overweight with a body mass index (BMI) of 26 or greater,” says White. (BMI is measure of body fat that’s calculated by dividing your weight in kilograms by the square of your height in meters.) While doubling up on the dose may seem like the solution, White says it’s unclear if a higher dosage will actually improve the rate of effectiveness in any way. “Two won’t hurt you, but it’s about $50 a pop and it’s not known whether it’s going to help,” she says.
The other option, Ella, remains effective at the same rate for women with BMIs up to 35. It was first developed in Europe and is more common in countries outside of the U.S. “It’s great because it’s at least as effective as Plan B in the first day after sex and remains that effective for five whole days after,” says White. “But there’s that wall of a prescription needed and not all pharmacies stock it. If you think you might have a use for it in your life, it’s not unreasonable to ask for a prescription in advance.”
No matter which option you choose, emergency contraception pills can reduce your risk of pregnancy by anywhere from 52 to 99 percent, depending on how soon you take it and the timing of sex related to your cycle. As White mentioned, taking the pills can throw off your period for a cycle, but you may want to consider taking a pregnancy test if you don’t get your period within six weeks of taking the medication.
“Taking repeated doses of either Plan B or Ella might make bleeding wonky for a while, which will make it hard to know when your next period is going to come,” says White. “So that might mean taking an extra pregnancy test or two if you’re nervous and having to wait it out, but there’s no harm done by repeating doses.”
If pills don’t sound like the right option for you, then you may want to consider another, lesser-known—but usually much more effective—choice: the copper IUD.
2. Copper IUD
“‘An IUD for emergency contraception?’ you say? “Yes!” exclaims White. “The copper IUD is the most effective form of emergency contraception we have and it’s not only highly effective for five days after sex, but you can then keep it in place if you want to so you’ll have a highly effective form of birth control going forward. If you never saw yourself as an IUD user, getting the copper IUD for emergency contraception doesn’t mean you have to keep it—you can just leave it in for a cycle and then take it out.”
The copper IUD works by preventing fertilization (only the copper IUD, not the hormonal IUD, has been studied as a form of emergency contraception). “It makes it really difficult for sperm to fertilize the egg,” says White. Having a doctor insert the copper IUD up to five days after sex can reduce the risk of pregnancy by up to 99 percent. The cost of an IUD varies a lot depending on whether you have insurance coverage and what type of plan you have (anywhere between $0 to $1,000), but it can be low cost and even free with many insurance plans, Medicaid, and some government programs. Talk to your insurance provider to find out if your plan covers an IUD.
This article is not intended to substitute for informed medical advice. You should not use this information to diagnose or treat a health problem or condition. Always check with your doctor before changing your diet, altering your sleep habits, taking supplements, or starting a new fitness routine.