Experts warn women to use effective contraception with drugs such as Wegovy and Ozempic as claims of increased fertility arise

Medications such as Wegovy and Ozempic, both of which contain semaglutide, have become hugely popular, not least because they can help people lose more than 10% of their body weight. Picture: Mario Tama/Getty

Claims that “skinny jabs” are fuelling an unexpected baby boom have led experts to warn women to pair their use with effective contraception.

Medications such as Wegovy and Ozempic, both of which contain semaglutide, have become hugely popular, not least because they can help people lose more than 10% of their body weight.

The drugs mimic a hormone in the body called GLP-1 that triggers an increase in the production of insulin, slows the rate at which food is digested in the stomach, and reduces appetite.

But as their use has boomed, so too have reports of women falling pregnant while using such medications — known as GLP-1 receptor agonists.

While studies confirming a link are lacking, experts say an association is plausible. According to Dr Karin Hammarberg of Monash University in Australia:

Women with obesity often have irregular or no periods because they don’t ovulate. Once they lose some weight, ovulation becomes more regular and this is how their fertility improves.

Research is under way to explore whether semaglutide could help boost ovulation in women with obesity and polycystic ovary syndrome (PCOS).

However, concerns have been raised over the safety of pregnant women using GLP-1 receptor agonists.

A spokesperson for Novo Nordisk, which makes Ozempic and Wegovy, said: “Pregnancy or intention to become pregnant were exclusion criteria in our trials with semaglutide in both obesity and type 2 diabetes. Therefore, there are limited clinical trial data with semaglutide use in pregnant women.” 

Animal studies have suggested semaglutide can cause foetal abnormalities.

According to Novo Nordisk, when semaglutide was given to pregnant rats, the unborn offspring showed both structural abnormalities and alterations to growth.

The preclinical safety information for Wegovy adds: “In developmental toxicity studies in rabbits and cynomolgus monkeys, increased pregnancy loss and slightly increased incidence of foetal abnormalities were observed at clinically relevant exposures.” 

While the company is now carrying out trials to explore whether such drugs are safe for pregnant women, at present it advises that semaglutide should not be used during pregnancy as it is not known if it may affect an unborn child.

“Therefore, it is recommended to use contraception while using this medicine,” the patient information leaflet for Wegovy states . 

“If you wish to become pregnant, you should stop using this medicine at least two months in advance. If you become or are pregnant, think you may be pregnant or are planning to have a baby when using this medicine, talk to your doctor straight away, as your treatment will need to be stopped.”