British Scientists Warn Weight-Loss Drug Might Harm Developing Babies

Using semaglutide as a fertility aid is risky and might cause harm during pregnancy, British scientists have warned.

Anecdotal reports suggest that some women, including those with fertility issues, unexpectedly became pregnant while using the Type 2 diabetes and weight loss drugs.

Stories so-called “Ozempic babies” have been published in outlets around the world.

In the U.K., several articles on popular news website MailOnline describe cases of “oops” babies, some featuring women with polycystic ovary syndrome, which can affect both weight and fertility.

But experts warn semaglutide hasn’t been tested in pregnancy and it’s not clear how safe it is for developing babies. Women who want to get pregnant, they added, should stop using the drugs months before they start trying.

What Is Semaglutide?

Semaglutide mimics a hormone called glucagon-like peptide-1 (GLP-1) that’s normally released in response to eating. This can make users feel fuller, among other effects.

Popular semaglutide drugs include Ozempic and Wegovy, both manufactured by Novo Nordisk.

They are not indicated as fertility treatments, and their packaging warns they should not be used during pregnancy.

What Does The Science Say About Pregnancy?

U.K. scientists warn effects of semaglutide on fertility remain uncertain — as do the risks of using the drug and pregnancy.

Several experts told the Science Media Centre that some women may be getting pregnant simply because weight loss itself can improve fertility.

Being overweight or obese can impact periods, ovulation and the implantation of immature eggs, said Nerys Astbury, a senior researcher in diet and obesity at the University of Oxford’s Nuffield Department of Primary Health Care Sciences. “Women living with obesity are more likely to have problems in conceiving, to suffer miscarriage, and are less likely to deliver live infants.”

Losing even 5 to 10% of body mass can help the body release eggs as normal, “and there is evidence that this increases chance of conception,” she added.

It’s plausible, she said, that women taking semaglutide while using an unreliable contraception method may fall pregnant in part because they’ve lost weight. Possible side effects like vomiting may also reduce the effectiveness of oral contraceptives.

It might be the case that there’s “nothing special about the drug — but the effect the drug has on promoting weight loss,” she said.

Without dedicated scientific research, the true impact of the drug on pregnancy and conditions that impact fertility remains unknown.

“Whether GLP-1 agonists can help with the management of other conditions e.g. in polycystic ovary syndrome, apart from weight loss is still a matter of research,” said Ying Cheong, professor of reproductive medicine at the University of Southampton. “Doctors should not be prescribing these medications without the appropriate indications.”

Semaglutide has caused “pregnancy complications and abnormalities in animal studies, and so women planning to be pregnant should be advised not take them,” she said.

It’s also important to have a balanced and varied diet during pregnancy to protect the baby, said Adam Balen, professor of reproductive medicine and surgery at Leeds Teaching Hospitals NHS Trust.

“Conceiving when not nutritionally stable may be harmful for the developing baby,” he said. “Overweight women should be taking appropriate vitamin supplements” like high-dose folate to reduce the risk of congenital anomalies.

Barbara McGowan, professor of endocrinology and diabetes at King’s College London and Guy’s and St Thomas’s Hospital, said that women taking semaglutide should use contraception to prevent pregnancy while on the drug.

They should also stop using semaglutide “at least 2 months before trying for fertility,” she added.