Is pregnancy a side effect of weight loss drugs?

When drugs Ozempic and Mounjaro, approved to treat Type 2 diabetes, also became known for their weight loss benefits, their demand skyrocketed. New versions of the drugs, known as Wegovy and Zepbound, were created and marketed as FDA-approved weight loss medications.

Then, something surprising happened: Not only did people taking the drugs report they lost weight, but some also found there might be another benefit — unexpected pregnancy. Nationwide, women who were taking the medications began sharing, primarily on social media platforms, that they were surprised to learn they were pregnant.

The babies that resulted have affectionately been labeled “Ozempic babies.”

“While I haven’t had any patients yet who are pregnant and were recently on weight loss drugs like Ozempic, a few colleagues have said they were seeing more patients on Ozempic coming back pregnant,” says Dr. Melody Besharati, an OBGYN with Sharp Rees-Stealy.

Why pregnancy is a possible side effect

Ozempic, Mounjaro, Wegovy and Zepbound are all in a class of drugs called GLP-1 receptor agonists. When taken, they are proven to improve blood sugar in adults with Type 2 diabetes; reduce the risk of major cardiovascular events, such as stroke and heart attack; and cause weight loss.

“Ozempic may help fertility by contributing to weight loss,” says Dr. Besharati. “In women with polycystic ovary syndrome, commonly called PCOS, for example, we know that even a modest weight loss of 5% can improve hormones, menstrual regulation, ovulation and, therefore, fertility potential.”

Additionally, while there is no evidence that Ozempic and other GLP-1 agonist drugs directly interact with birth control, some of the drugs’ side effects, including delayed gastric emptying, nausea and diarrhea, may interfere with proper gut absorption of oral birth control pills. This can make the contraceptives less effective.

Why GLP-1 agonists should not be used when trying to get pregnant

Though the medications may have played a role in the pregnancies of some women, they should not be used when trying to conceive. Few studies have been performed to determine how they might affect a pregnancy and infant.

However, according to a report shared by the National Institutes of Health, animal studies of the medications reported offspring that were smaller than usual as well as a higher chance for miscarriage, though the reasons were unclear.

“It is not yet known if GLP-1 agonists like Ozempic can negatively affect an unborn fetus or if they can pass through breast milk,” Dr. Besharati says. “Therefore, the makers recommend discontinuing use two months before becoming pregnant.”

Women taking GLP-1 agonists and the birth control pill should also use a barrier method, such as condoms. An alternative birth control option, for example, an IUD or implant, can also be considered, Dr. Besharati says, as neither would be impacted by gut absorption.

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