How to Take and Next Steps

There are two forms of emergency contraception: over-the-counter and prescription pills you take orally, and intrauterine devices (IUDs) that a healthcare professional inserts.

That means healthcare professionals currently don’t have a concrete answer as to when emergency contraceptive pills become less effective or ineffective.

Experts need more research to understand whether doubling the dose can increase efficacy in people with a higher weight or BMI.

The copper IUD can be the most effective form of emergency contraception, regardless of weight or BMI.

If you have the option, talking with a healthcare professional may be helpful. They can recommend the best emergency contraceptive for your individual needs.

“Ella is more effective when taken at any point within 120 hours, or 5 days, after sex than any other emergency contraceptive pill option,” said Sophia Yen, MD, co-founder and CEO of Pandia Health, an online birth control provider.

Blocking progesterone also thins the uterine lining, so implantation is unlikely to occur even if sperm can fertilize the egg.

According to Planned Parenthood, ella can be most effective for people with a BMI of 30 or less. It can be less effective — potentially ineffective — for people with a BMI of 35 or higher. It’s typically more effective than levonorgestrel from 3 to 5 days after intercourse without barrier methods.

Ella is available by prescription only. If you have a primary care physician or gynecologist, they can prescribe ella for you.

You can get a prescription through your local health department, a community clinic like Planned Parenthood, or a telemedicine platform like Nurx.

Ella usually costs around $50, but some providers offer the medication for free or at a reduced cost for people who qualify. Insurances and Medicaid typically cover the medication.

The most ubiquitous emergency contraceptive on the market, Plan B, contains a synthetic version of progesterone called levonorgestrel. The synthetic hormone can help delay ovulation, reducing the risk of potential fertilization.

“Levonorgestrel pills have been shown to be 89% effective if taken up to 72 hours, or 3 days, after intercourse without any barrier methods,” said Cristin Hackel, a nurse practitioner at Nurx, a telemedicine provider.

“They do continue to work 72 to 120 hours, or 5 days, after intercourse, but to a much lesser degree,” explained Hackel.

According to Planned Parenthood, levonorgestrel-based pills can be most effective for people with a BMI of 24 or less. They can be less effective — potentially ineffective — for people with a BMI of 25 or higher.

You can purchase Plan B and other levonorgestrel pills without a prescription at most drugstores, including CVS, Rite-Aid, and Walgreens. Some grocery stores and many online retailers also offer the medication.

You can also get the medication at your local health department, a community clinic like Planned Parenthood, or through a telemedicine platform like Nurx.

Plan B usually costs around $50. Generic levonorgestrel pills aren’t as widely available as Plan B — you may have better luck finding them online — but they’re usually less expensive.

Many providers offer financial assistance, and people who have insurance or Medicaid can usually get the medication at no cost.

You can take some birth control pills as emergency contraception when you take them in higher-than-usual amounts. The uptick in hormones can help delay ovulation and prevent implantation.

“The Yuzpe method involves taking one first dose within 72 hours and a second dose taken 12 hours later,” explained Hackel.

While convenient, most experts don’t recommend it if other options for emergency contraception are available.

“The Yuzpe method is less effective than Plan B and ella and comes with more side effects,” said Hackel.

Older research found the Yuzpe method to be 56% to 86% effective, depending on how soon after sex people took the medication.

The sooner you use emergency contraception, the more effective it may be. That said, you have options if 72 hours, 3 days, or more pass.

You can use whatever method you have available for up to 120 hours, or 5 days, after sex. The ulipristal acetate pill branded as ella can be the most effective emergency contraceptive pill after 72 hours, or 3 days.

The copper IUD may be the most effective form of emergency contraception overall.

Gabrielle Kassel (she/her) is a queer sex educator and wellness journalist who is committed to helping people feel the best they can in their bodies. In addition to Healthline, her work has appeared in publications such as Shape, Cosmopolitan, Well+Good, Health, Self, Women’s Health, Greatist, and more! In her free time, Gabrielle can be found coaching CrossFit, reviewing pleasure products, hiking with her border collie, or recording episodes of the podcast she co-hosts called Bad In Bed. Follow her on Instagram @Gabriellekassel.