You may have heard that taking emergency contraception like Plan B during ovulation makes it less effective, and unfortunately, that’s one rumor that’s true (more on that below). But there are a host of other factors that can make emergency contraception fail, from not taking it soon enough to continuing to have unprotected sex after you take it. The good news is, emergency contraception exists in several different forms, so chances are, there’s one that will work for you. That said, taking it properly is crucial for it to protect you to the fullest extent. Here are six things you should know about taking emergency contraception to avoid pregnancy—including whether Plan B is effective if you are already ovulating.
First, here’s what you need to know about emergency contraception.
There are a few types of emergency contraception, and some work better than others. According to Planned Parenthood, you basically have two options:
Go to your doctor to get a Paragard IUD within five days of having sex without protection. Paragard creates a toxic environment for sperm, and it prevents pregnancy more than 99.9 percent of the time. That’s why it’s considered the most effective type of emergency contraception, according to Planned Parenthood.
Take an emergency contraceptive pill (often referred to as the morning-after pill) within five days of unprotected sex. There are two types of morning-after pills: A brand called Ella uses the drug ulipristal acetate to delay ovulation, and according to Planned Parenthood, is the most effective type of morning-after pill. The only hitch: You need a prescription to get it (that said, you can get a fast medical consultation and prescription with next-day delivery online). Your other option is an OTC morning-after pill like Plan B or Next Choice, both of which use levonorgestrel, a synthetic version of the hormone progesterone, to delay ovulation. These pills work best the sooner you take them, but you can take them up to five days after unprotected sex, according to Planned Parenthood.
Your final option is to take multiple doses of regular birth control pills as emergency contraception—and no, that does not mean simply “doubling up.” Popping two birth control pills is typically recommended when you’ve missed just one dose of your birth control, but it doesn’t work as emergency contraception. For emergency contraception, you have to take more than two, and the amount you need depends on the brand you use. Known as the Yuzpe method, this method has been around since the ’70s. That said, you have to be precise about it (read more here), so talk to your doctor or pharmacist about your specific birth control before trying it. They can tell you if this or another EC option would be best for your situation.
Now that you understand your options, here, ob/gyns explain the factors that can make emergency contraception fail.
1. You don’t take it soon enough.
Morning-after pills like Plan B and Next Choice are effective if you take them within five days of unprotected sex. The major caveat here is that they work best when taken within 72 hours, then the efficacy starts dropping. Within three days after unprotected sex, these kinds of morning-after pills are between 75 and 89 percent effective at preventing pregnancy, according to Planned Parenthood. “The sooner you take it, the better it’s going to work,” Mary Jane Minkin, M.D., a clinical professor of obstetrics and gynecology at Yale Medical School, tells SELF. Although levonorgesterel-based options like Plan B and Next Choice prevent pregnancy up to five days after unprotected sex, think of those first 72 hours as prime time.
Ella, the prescription morning-after pill, is also effective for up to five days after unprotected sex, but it’s equally as effective the entire time, Katharine O’Connell White, M.D., M.P.H., director of fellowship in family planning, Boston University/Boston Medical Center, tells SELF. Ella decreases your risk of getting pregnant by 85 percent if you take it within the appropriate window.
Paragard also needs to be inserted within that five-day window in order to be effective.
2. You throw up after taking EC.
Years ago, emergency contraception relied on estrogen to do its job, Dr. Minkin explains. “The estrogen in these things—they used mondo doses—used to make people nauseated,” she says. Now, forms of EC like Plan B and Ella don’t rely on estrogen, so nausea is less likely (in fact, morning-after pill side effects are short-lived and cause little more annoyance than bleeding between periods or nausea, according to Planned Parenthood. That said, nausea can still happen, especially due to nerves. If you opt for the method of taking multiple birth control pills as your EC, there’s a decent chance you could ralph. “[Taking multiple birth control pills is] great in a pinch, but it often leads to nausea and vomiting, which are a risk factor for failure,” Dr. White says.
No matter what, if you throw up within an hour or so of taking EC, you’ll need another dose. Your body might not have had enough time to metabolize it, Dr. White explains. “It’s really unlikely that this would happen after around an hour, but if you ever vomit and can see a pill, that’s a concern,” Dr. White says, and you should probably take another to play it safe.
3. Your BMI is over a certain number.
Although BMI is a tricky measure for things like health, it does come into play with EC. If your BMI is over 25, morning-after pills like Plan B are less likely to be effective. “It has to do with the distribution of the drug,” Dr. White explains. Some science suggests Ella may also become less effective at higher BMIs, though it’s not yet clear how true this may be.
“Being obese or overweight doesn’t render emergency contraception ineffective, just less effective,” Dr. Minkin says. In this instance, the copper IUD can be an especially great option for EC. “Paragard will work very nicely as emergency contraception in someone with a higher BMI, and the other advantage is it will give you long-term contraception anyway,” Dr. Minkin says.
4. You start hormonal birth control right after taking Ella.
After a slip-up requiring emergency contraception, it might seem like you should immediately hop back on the non-baby-making train by getting yourself a scrip for birth control, stat. But you shouldn’t start or continue any form of hormonal birth control within the first five days of taking Ella, Dr. White explains. “Another hormonal birth control method can decrease Ella’s efficacy,” she says. In return, Ella can mess with hormonal birth control’s mechanisms, according to its website. To be safe, after using Ella, use condoms until your next period, and don’t use hormonal birth control until five days have passed.
5. You took Plan B during ovulation.
Now for the mother of all questions: Is Plan B effective if you are already ovulating? Here’s the deal: Preventing pregnancy with Plan B—or any form of EC—is all about timing. Sperm can live inside your body for up to five days after sex, waiting for an egg to join up with. If you ovulate during that time, the sperm and egg can meet and cause pregnancy. Morning-after pills work by temporarily stopping ovulation, but if your ovary has already released an egg, your EC won’t keep you from getting pregnant, according to Planned Parenthood. So, if you happen to have unprotected sex during your fertile window—four days before you ovulate, the day you ovulate, and the day after—you’re just naturally more likely to get pregnant, Dr. White explains.
So what should you do if you had unprotected sex during ovulation? Your best bet is the Paragard IUD. “It’s the best emergency contraception we have. Because it works by inhibiting sperm, the timing in your cycle doesn’t matter as much,” Dr. White says. Of course, getting an IUD is way different than taking the morning-after pill, but it may be worth it if you’re looking for the most effective EC possible.
6. You have more unprotected sex after you take EC.
Sometimes people think that after a dose of EC, they a sexual get-out-of-jail-free card, Dr. White explains. That’s not true. “Ovulation is just delayed, not stopped, so further acts of unprotected sex put you in the line of fire,” she says.
Once more, with feeling: Everyone makes mistakes. If you need emergency contraception, there’s no reason to feel down on yourself. It only becomes somewhat concerning if it becomes a habit, because it means there might be a better birth control option out there for you. “If you find yourself needing morning-after contraception on several occasions, it’s not dangerous, but we can do better,” Dr. Minkin says. “If you’re sick of taking birth control pills, we can get you an IUD, the Nexplanon implant, or something else—there are lots of options, and you don’t have to rely on morning-after contraception.”