What is emergency contraception and how does it work? Experts explain.

·6-min read
Box of Plan B (levonorgestrel).
Emergency contraception methods, like Plan B, help prevent pregnancy up to five days after having unprotected sex. (Photo: Getty Images)

Although emergency contraception has been around for years — the FDA approved it as a prescription pill in 1998, followed by an over-the-counter option in 2006 — there are still some people who either don’t understand how it works or confuse it with abortion pills. But they are not the same thing.

Emergency contraceptive pills prevent pregnancy up to five days after having unprotected sex, according to Planned Parenthood. They do not “induce abortion,” Dr. Emily Godfrey, associate professor of ob-gyn at the University of Washington Medical Center, tells Yahoo Life, adding that if you’re already pregnant, “it does not harm a pregnancy if you use it.”

Here’s what you need to know about emergency contraception.

What is emergency contraception?

Dr. Melissa Myo, clinical instructor of obstetrics and gynecology with the Keck School of Medicine of USC, tells Yahoo Life, “In broad terms, emergency contraception refers to any method that can be used shortly after unprotected intercourse to prevent pregnancy.”

What are the different types of emergency contraception, and how do they work?

The most commonly known method is in pill form, of which there are two types on the market.

The first type contains levonorgestrel, such as over-the-counter Plan B One-Step, My Way, Take Action and generic versions. Levonorgestrel is a type of progestin that’s found in other oral contraceptive pills, but for emergency contraception it’s “at a higher, one-time dose to delay ovulation,” explains Myo.

The second type contains ulipristal acetate and is sold under the brand name Ella, which requires a prescription, and it also comes in generic form. “Ella acts on progestin receptors and also inhibits ovulation,” says Myo.

Essentially, both pills work “by delaying the presence of an egg,” explains Myo, “so that a sperm can’t find one and fertilize it.”

Both types of pills can be taken up to five days after having unprotected sex to prevent pregnancy. But Planned Parenthood notes that “they work much better if you take them during the first three days.”

But pills aren’t the only form of emergency contraception. There’s another type that “people sometimes do not know about,” says Myo — and that’s a copper IUD. She explains that copper IUDs, which are inserted by a health care practitioner, primarily work “by interfering with sperm function and can be a good option for someone who is interested in not only preventing this pregnancy but also in starting a longer term contraceptive method.”

Experts recommend that the copper IUD be inserted within five days of unprotected intercourse, “but is found effective up to 10 days in some studies,” points out Myo.

There’s also a hormonal type of IUD with the same levonorgestrel hormone as Plan B, which was “recently found to be just as effective as the copper IUD for the purposes of emergency contraception when placed within five days after intercourse,” she says.

How effective is emergency contraception?

According to the World Health Organization (WHO), when a copper IUD is inserted within five days of unprotected sex, it’s more than 99% effective in preventing pregnancy.

Emergency contraceptive pills can prevent up to over 95% of pregnancies if taken within five days of unprotected sex, according to WHO.

Weight appears to be a factor, though, when it comes to the effectiveness of emergency contraceptive pills. According to Planned Parenthood, emergency contraceptives that contain levonorgestrel may not work well in people who weigh 155 pounds or more — in that case, prescription Ella would be a better option.

However, Planned Parenthood says that Ella may not work in people weighing 195 pounds or more. IUDs, on the other hand, work regardless of a person’s weight.

Is one form of emergency contraception more effective than the others?

Godfrey says that, when it comes to emergency contraception, “the best and most effective” type is an IUD. “It’s been proven over and over again that it will absolutely prevent an unplanned pregnancy,” she says.

According to Cleveland Clinic, the copper IUD is the “most effective of all, working 99% of the time, no matter your weight.” That’s followed by the prescription pill Ella, which Cleveland Clinic states is “more effective” than over-the-counter methods “because it works closer to the time of ovulation.”

However, over-the-counter emergency contraceptive pills have an advantage since they’re easier for most people to access (and have no age restrictions), while Ella and IUDs require getting an appointment to see a health care practitioner.

Above all, the best method to use is “the most effective method you have available,” notes Cleveland Clinic.

Are there any side effects?

Common side effects that people might experience include headache and nausea. “Some people experience changes to their menstrual bleeding during that month, and most changes resolve without any other treatment,” says Myo, who points out that “no serious complications have been linked to the use of emergency contraceptive pills in scientific research.”

Also, because emergency contraceptive pills are taken as a one-time dose, “even people who have medical issues that might prevent them from being able to safely take oral contraceptive pills long-term can take emergency contraceptive pills,” she says. But it’s always smart to check with your health care provider first.

Why is it important to have access to emergency contraception?

Experts, like Myo, say that it’s “incredibly important” to have access not only to emergency contraception, but also to all forms of contraception. “No one form of contraception is perfect for everyone, and every individual has their own goals for their life and their wishes for how they live in their body,” Myo says.

This is particularly important as reproductive rights are being restricted in certain parts of the country. “The threat of reducing or eliminating contraception is a direct threat to people’s abilities to live the life they want,” says Myo. “The logic espoused by Justice Alito in the [Supreme Court] draft opinion also hints at future attempts to restricting our access to contraception. In clinical practice, we often will ask our patients their reproductive goals: Do you plan to be pregnant in the next year? When do you plan to be pregnant? How many children, if any, would you want in your lifetime? These questions help us tailor our recommendations for contraceptive methods that will hopefully help our patients reach their goals.”

In light of the threats to Roe v. Wade, Myo says that it’s “now more important than ever” to discuss issues such as contraception, including emergency contraception, with your doctor. “You can fill a prescription or purchase pill-form emergency contraceptives,” she says. “You can ask your doctor for a prescription of a year’s worth of oral contraceptive pills so that you don’t risk missing doses.”

But, Myo adds, “even with all the preparations, all methods have risk of failure, and it is not a replacement for access to safe abortion. Even if contraception remains available to us, we will still have to continue to push for abortion access for everyone.”

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