Weight loss drugs like Ozempic could mess with your birth control — and get you pregnant

A UK watchdog is urging women on GLP-1 weight-loss drugs like Ozempic and Mounjaro to use effective forms of birth control after receiving more than 40 pregnancy-related reports linked to the medications.

The warning comes as women flood social media with stories of their so-called “Ozempic babies” — including surprise pregnancies while on the pill.

Trying to shed pounds, not grow a baby bump? Here’s what you need to know about GLP-1s, pregnancy and the best contraception options to stay protected.

What’s in your GLP-1?

Several GLP-1 drugs dominate the market, including Ozempic and Wegovy. Both contain semaglutide, an active ingredient that mimics a natural hormone in the body that boosts insulin production, slows digestion and curbs appetite.

Then there’s Saxenda and Victoza, powered by liraglutide, which functions in a similar way.

Newer drugs like Mounjaro and Zepbound rely on tirzepatide, a key ingredient that targets a second hormone involved in appetite and blood sugar control.

A surprise side effect

While gastrointestinal symptoms like nausea, vomiting and diarrhea are common with GLP-1s, the surprise side effect making waves is unexpected pregnancy.

The UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) has received 28 reports related to pregnancy in patients on tirzepatide, and nine each for semaglutide and liraglutide.

In an alert this week, the agency warned that tirzepatide may reduce the effectiveness of oral contraceptives, especially in women with higher body weight. As a result, it recommended using barrier methods like condoms while on drugs like Mounjaro.

So far, there’s no evidence that GLP-1s affect non-oral birth control like IUDs, implants, patches, or rings, according to the UK’s Faculty of Reproductive Healthcare.

And yes, the advice applies even to women previously told they were infertile. GLP-1s have been shown to boost fertility by aiding weight loss, reducing inflammation and improving insulin sensitivity — leading some to conceive just months after starting treatment.

Can you take GLP-1s while pregnant?

Experts say no — at least not yet. There’s not enough data to confirm whether GLP-1s are safe during pregnancy.

While a some human studies suggests there is no harm in first-trimester use, testing in animals has shown the drugs could increase the risk of miscarriage and birth defects.

Another reason to skip GLP-1s while pregnant: they suppress your appetite and can trigger gastrointestinal issues, which may lead to nutrient deficiencies that impact fetal development.

The drugs should also be avoided during breastfeeding, since there’s not enough research to confirm safety for infants.

Trying to conceive? Here’s the timeline

If you’re planning to get pregnant, the MHRA recommended stopping GLP-1s before you start trying to conceive and giving your body time to clear the drugs.

For semaglutide users, that means quitting at least two months ahead.

If you’re on tirzepatide, stop one month before trying.

Liraglutide clears the system faster, so you can stop right before you start trying to conceive.