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Birth control · 2 min read

Emergency contraception on a GLP-1: what to know

Missed a backup window on Zepbound or vomited your pill? Here is what to know about emergency contraception options while on a GLP-1, and who to ask fast.

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Sourced from FDA labels and professional guidelinesChecked by the evenwell team, not a clinician · Updated

Key points

If you missed a backup window, vomited your pill, or a condom broke, here’s what to do.

Your options

OptionHow it worksTime window
Levonorgestrel pill (e.g. Plan B)Over the counterBest within 72 hours, sooner is better
Ulipristal pill (ella)PrescriptionUp to 5 days
Copper IUDPlaced by a clinicianUp to 5 days, most effective option

ACOG’s ordering is worth knowing: the copper IUD is the most effective emergency contraception, followed by ulipristal, then levonorgestrel.

Does a GLP-1 affect EC pills?

EC pills are swallowed, so people reasonably ask whether a GLP-1’s slower stomach emptying could affect them. GLP-1 labels don’t address this, and it hasn’t been well studied. Because of that uncertainty, it’s worth asking a pharmacist whether a copper IUD or a particular pill makes more sense for you.

Body weight and EC

ACOG notes that levonorgestrel (Plan B and its generics) may be less effective at a BMI of 25 or above, and that it appears to lose effectiveness at a lower weight than ulipristal does. The copper IUD’s effectiveness doesn’t change with weight at all.

One thing ACOG is firm about: no one should be refused emergency contraception, or talked out of it, because of her weight. A less effective option taken now beats a better one you didn’t get. A pharmacist can help you choose.

What to do right now

  1. Don’t wait. EC works best early.
  2. Call or visit a pharmacy, or your OB-GYN or telehealth provider.
  3. Say: “I need emergency contraception. I’m on [your GLP-1] and [your birth control].”
  4. Take a pregnancy test if your next period is late.

After you’ve used EC

Common questions

Can I take Plan B while on Zepbound?

There’s no specific label advice. Ask a pharmacist, who can help you choose the best option.

Will EC affect my GLP-1?

There’s no known interaction on the labels, but tell your prescriber you used it.

Is EC the same as an abortion pill?

No. EC helps prevent pregnancy. It doesn’t end an existing pregnancy.

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If this applies to you, it's worth asking your prescriber about. evenwell doesn't replace medical advice.

Sources

verified ACOG: emergency contraception open_in_new verified CDC U.S. Selected Practice Recommendations for Contraceptive Use open_in_new
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evenwell is for tracking and education. It doesn't diagnose or replace medical advice. Medical disclaimer © 2026 Keen Digital