With claims suggesting that weight-loss jabs may be fuelling an unexpected increase in pregnancies, experts have recommended that women pair the use of drugs like Wegovy and Ozempic with effective contraception.
The Facebook group “I got pregnant on Ozempic” has more than 750 members, while threads on the social network site Reddit include similar such experiences, reports The Guardian.
Although studies confirming a link are lacking, experts say an association is plausible.
“Women with obesity often have irregular or no periods because they don’t ovulate. Once they lose some weight, ovulation becomes more regular, which is how their fertility improves,” said Dr Karin Hammarberg of Monash University in Australia.
Research is under way to explore whether semaglutide could help boost ovulation in women with obesity and polycystic ovary syndrome (PCOS) – a condition which can cause irregular periods, weight gain, and infertility, among other symptoms.
However, concerns have also been raised over the safety of pregnant women using GLP-1 receptor agonists.
A spokesperson for Novo Nordisk, maker of 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.”
While evidence in humans is lacking, 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 pre-clinical 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.
But some women have reported becoming pregnant when using GLP-1 receptor agonists despite using hormonal contraception, leading to speculation the drugs might interfere with such methods of birth control.
Professor Sir Stephen O’Rahilly, co-director, of the Wellcome-MRC Institute of Metabolic Science, said the question of whether GLP-1 receptor agonist drugs can interfere with the efficacy of oral contraceptives is, so far, largely unanswered.
“People treated with these drugs can develop gastrointestinal side effects including diarrhoea, so it is not implausible that some women may find that their oral contraceptive pill is, at least intermittently, not as reliably absorbed as it was previously,” he said.
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