Women on weight-loss drugs report surprise pregnancies, giving hope to those made infertile by hormonal disorder PCOS

As the pounds melted off, there was soon another reason to celebrate. She was expecting.

“The weight loss, that’s likely what jump-started it,” she said. “I couldn’t believe it.”

Stories like these are encouraging doctors to use these GLP-1 (glucagon-like peptide 1) drugs – mainly used to help manage blood sugar levels in people with type 2 diabetes, and more recently to treat obesity – to treat polycystic ovary syndrome (PCOS), one of the leading causes of infertility globally.

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Yet they are doing so without much data on the drugs’ impact on pregnancy.

“The ‘oops’ babies on Ozempic and Wegovy are happening all over the place,” said Melanie Cree, director of the PCOS clinic at Children’s Hospital Colorado in the US.

“It’s very exciting, but it’s a bit scary because we’re moving forward without all the data.”

GLP-1 drugs have been marketed for nearly 20 years to treat diabetes, and their use in obesity is fuelling a new market that is expected to hit US$100 billion in 2030.

The problem is that companies have not systematically studied GLP-1’s use in PCOS – and do not plan to any time soon.

In the absence of data, researchers are doing studies of their own to figure out if the drugs work for PCOS, and US regulators have asked the companies to collect any information they can about their use during pregnancy.

Long-term safety data limited

Still, the study’s authors said additional confirmation is needed, especially in women without diabetes.

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Researchers from Copenhagen, Denmark, concurred last year in a review of GLP-1 drugs, saying that there is “limited information on their long-term safety, particularly concerning pregnancy outcomes”.

Reasons for concern come mostly from animal experiments. The active ingredient in Novo Nordisk’s drugs, semaglutide, has been linked to increased birth defects in animals.

Similar studies of Eli Lilly’s drugs have shown there “may be risks to the fetus” from exposure during pregnancy, the company said.

No one is exactly sure how – or even whether – the drugs contribute to women becoming pregnant.

Weight loss is known to boost fertility in women with PCOS, and studies have shown that Saxenda, an older obesity drug, also raised pregnancy rates in women with the disorder who were overweight.

GLP-1s may also have hormonal effects that promote fertility and may blunt the impact of oral contraceptives. Some experts think the drugs might even have a role in male infertility.

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Rekha Kumar, a reproductive endocrinologist at Weill Cornell Medicine in New York, says GLP-1 drugs “wake up the ovaries”, resetting the reproductive environment for normal function.

After treating patients with infertility and obesity for more than 15 years, one thing is clear, Kumar said: “These patients are becoming very fertile.”

Pregnant people and those planning to get pregnant were excluded from trials of GLP-1s. Trial participants have been required to use contraception, and treatment was discontinued for those who became pregnant during clinical trials of Mounjaro and Zepbound, Eli Lilly said.

Conflicting advice

Experts are split on how soon patients should stop taking the medications before a planned pregnancy. Some doctors are telling patients that up to four weeks is safe; others say it is fine to keep using them up until the time of pregnancy.

Wegovy’s label says people should stop taking the drug at least two months before trying to get pregnant, while Zepbound’s recommends that people who become pregnant stop the drug.

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In Colorado, Cree is running a study to find out how Novo Nordisk’s Wegovy affects ovulation in women with PCOS, but ongoing supply problems with the popular drug present a challenge. Novo Nordisk will not provide free supplies because the patients will not be on birth control, she said, a decision she called “very disappointing”.

Meanwhile, a study found that the number of women exposed to GLP-1 drugs during early pregnancy appears to be increasing, as more turn to them for diabetes and other conditions.

The private Facebook group “I got Pregnant on Ozempic” has 630 members; on TikTok, dozens have said they have become pregnant while taking a GLP-1 drug.

The US Food and Drug Administration asked Novo Nordisk to set up a registry to collect data on those who got pregnant while taking Wegovy, but the company has yet to share any results.

It is also required to do an additional pregnancy study using insurance claims or electronic medical records, the FDA said.

Eli Lilly is planning to set up a similar registry but declined to say when. Meanwhile, Cree and a handful of researchers are scrambling to set up their own databases to track pregnancy outcomes in GLP-1 patients.

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PCOS symptoms’ improve ‘significantly’

Those with the condition frequently make too much testosterone, leading to effects like extra hair growth, acne and weight gain, and blocking ovulation. They also do not respond properly to insulin, and the weight-loss effects of GLP-1s may improve sensitivity to the hormone.

The new drugs “are not going to cure you, but [they are] going to improve the symptoms significantly”, said Ricardo Azziz, a PCOS expert and professor at the University of Alabama at Birmingham and State University of New York.

Still, he also thinks more data is needed before doctors recommend the drugs for fertility.

People like Leggett, who got pregnant on a weight-loss drug, have some questions. She sometimes wonders why her daughter is smaller than other kids the same age.

“She’s teeny-tiny,” Leggett said. “I’d like to know more about that.”