Claims that “skinny jabs” are fueling 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 very popular, especially because they can help people lose more than 10% of their body weight.
The drugs work by mimicking a hormone in the body called GLP-1 that causes an increase in the production of insulin, slows down the rate at which food is digested in the stomach and reduces appetite.
But as their use has increased, so have reports of women becoming pregnant while using such medications – known as GLP-1 receptor agonists.
The Facebook group “I got pregnant on Ozempic” has more than 750 members, while threads on the social networking site Reddit are full of anecdotes of such experiences.
While studies confirming a link are lacking, experts say an association is plausible.
“Women with obesity often have irregular or no periods because they do not ovulate. Once they lose some weight, ovulation becomes more frequent and that’s how their fertility improves,” said Dr Karin Hammarberg from Monash University in Australia.
Research is ongoing to investigate whether semaglutide can help increase ovulation in women with obesity and polycystic ovary syndrome (PCOS) – a condition that can cause, among other things, irregular periods, weight gain and infertility.
However, concerns have been raised about the safety of pregnant women using GLP-1 receptor agonists.
A spokesman for Novo Nordisk, the company that makes Ozempic and Wegovy, said: “Pregnancy or intention to become pregnant were exclusion criteria in our trials of semaglutide in both obesity and type 2 diabetes. Therefore, there are limited clinical trial data with the use of semaglutide in pregnant women.
While evidence in humans is lacking, animal studies have suggested that semaglutide may cause fetal abnormalities.
According to Novo Nordisk, when semaglutide was given to pregnant ratsthe unborn offspring showed both structural abnormalities and changes in 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 fetal abnormalities were observed at clinically relevant exposures.”
While the company is now conduct trials to investigate whether such drugs are safe for pregnant womencurrently, it recommends that semaglutide should not be used during pregnancy, as it is not known whether it can affect an unborn child.
“Therefore, it is recommended to use contraception while using this medicine,” said the patient information leaflet for Wegovy states. “If you want to get pregnant, you must stop using this medicine at least two months before. If you become pregnant or are, think you may be pregnant or plan to have a baby while using this medicine, talk to your doctor immediately, as your treatment will need to be stopped.”
But some women reported that they had become pregnant when GLP-1 receptor agonists are used despite the use of hormonal contraception, leading to speculation that the drugs may interfere with such methods of birth control.
Prof Sir Stephen O’Rahilly, associate director, of the Wellcome-MRC Institute for Metabolic Science, said the question of whether GLP-1 receptor agonist drugs could interfere with the effectiveness of oral contraceptives was so far largely unanswered.
“People treated with these drugs can develop gastrointestinal side effects, including diarrhoea, so it is not unlikely that some women may find that their oral contraceptive pill, at least intermittently, is not as reliably absorbed as before,” he said.
“A pragmatic response to this situation might be to suggest that for women who are on the pill and are very keen to avoid pregnancy, that while experiencing active weight loss on GLP-1. [receptor agonists]they may consider themselves at higher risk of pregnancy and use additional methods, such as barrier contraception, until their weight stabilizes, after which it seems likely that contraceptive effectiveness will return to normal.”
Hammarberg agreed. “Stories of women on semaglutide becoming pregnant while on the pill are anecdotal stories and we must remember that this also happens among women who are not using semaglutide. Some speculate that semaglutide may alter the absorption of the pill, but as far as I know there is no evidence that this is the case,” she said.
“To be doubly sure that unplanned pregnancy does not occur, it may be wise for women on Ozempic and similar drugs to use condoms and of course an IUD would also be a very safe option.”
