Weight-loss drug Ozempic could lead to birth defects

Ozempic’s manufacturers say it is not safe to take it while trying to conceive – Oscar Wong/Moment RF

Women have been warned against getting pregnant while on Ozempic, amid fears that the celebrity weight-loss drug is being misused in the United States to boost fertility.

Several women claim to have conceived while having injections of the GLP-1 hormone-mimicking drug, which was originally developed for diabetes.

This has led some doctors in the US to prescribe the drugs off-label to treat polycystic ovary syndrome (PCOS), one of the leading causes of infertility in women.

Now British doctors have criticised the practice, warning that animal studies have shown the drug can lead to complications and birth defects.

They advised women to always use contraception when having the injections, and stop taking the drug at least two months before trying for a baby.

‘Known to cause abnormalities’

Prof Ying Cheong, professor of reproductive medicine and honorary consultant in reproductive medicine and surgery at the University of Southampton, said: “The drug is known to cause pregnancy complications and abnormalities in animal studies, and so women planning to be pregnant should be advised not to take [it].

“Whether GLP-1 agonists can help with the management of other conditions, eg in PCOS, apart from weight loss is still a matter of research, hence doctors should not be prescribing these medications without the appropriate indications.”

GLP-1 agonists, such as semaglutide and liraglutide, were originally developed for controlling blood sugar levels in people with Type 2 diabetes. But doctors prescribing the medication soon realised it was helping people to lose weight.

Ozempic has been prescribed off-label for weight loss. Semaglutide is prescribed on the NHS at a higher dose to treat obesity under the brand name Wegovy.

So many women have become pregnant after the injections that the phenomenon has been labelled “Ozempic babies” or “oops babies”.

Experts said there were plausible reasons that women might become pregnant because of the drug, but urged caution.

Prof Charles Kingsland, chief medical officer at Care Fertility, said:  “The drug Ozempic has a product licence for the treatment of diabetes. There is little data on its use in pregnancy or for those wishing to get pregnant, and, as such, it should not be used in these cases.

“It may help in weight loss, which is an independent factor for fertility enhancement, but the drug should not be used as an aid to lose weight for those wishing to enhance fertility.”

Losing a few pounds lowers hormone levels

Many experts believe that it is not the drugs themselves, but the benefits they bring, that are behind the unexpected pregnancies.

Fat cells produce oestrogen, which can have a negative impact on fertility, so losing a few pounds can help lower hormone levels and regulate menstruation and ovulation, with some women reporting their periods return “like clockwork”.

The drugs also work by delaying the stomach from emptying, which could prevent oral contraceptives from being absorbed effectively by the body.

Many of the GLP-1 agonist treatments have side-effects of vomiting and diarrhoea, which could also lessen the impact of contraceptives – and several studies have shown that weight loss boosts sexual function and activity.

‘Women with obesity may struggle to conceive’

Dr Nerys Astbury, senior researcher in diet and obesity at the University of Oxford, said: “Excess adiposity, known as overweight or obesity, can disrupt regular menstruation, ovulation, and implantation of fertilised oocytes, and women living with obesity are more likely to have problems in conceiving, to suffer miscarriage, and are less likely to deliver live infants.

“Losing a modest amount of weight, equivalent to 5-10 per cent of initial body mass, can correct anovulation due to obesity, and there is evidence that this increases chances of conception.

“Whilst some doctors are prescribing Semaglutide off-label to women with PCOS is not clear whether it’s safe to use in women during pregnancy, and should not be used as a method to treat infertility until research demonstrating safety and effectiveness is available, and until regulatory approval for use in those before and during pregnancy.”

Ozempic’s producer, Novo Nordisk, recommends women should stop taking the weight-loss drugs at least two months before a planned pregnancy.

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