Women in the UK have been urged to use effective contraception if they are using weight loss drugs after dozens of reports of unintentional pregnancies.
The Medicines and Healthcare products Regulatory Agency (MHRA) warning said women taking popular "skinny jabs" like Ozempic, Mounjaro and Wegovy should "use a barrier form of contraception and do not rely on oral contraception".
The warning comes after the agency received 40 reports relating to unintended pregnancies while using such weight loss drugs.
Ying Cheong, a consultant in reproductive medicine at the University of Southampton, called the MHRA's advice "both timely and necessary".
"Gastrointestinal side-effects such as vomiting and diarrhoea can impair oral contraceptive absorption, increasing the risk of unintended pregnancy," she said.
The warning from the MHRA urged women to use "effective contraception while taking these medicines and, in some cases, for up to two months between stopping the medicine and trying to get pregnant."
It also made clear that these drugs "must not be taken during pregnancy, while trying to get pregnant, or during breastfeeding."
"Anyone who gets pregnant while using them should speak to their healthcare professional and stop the medicine as soon as possible… because there is not enough safety data to know whether taking the medicine could cause harm to the baby," it added.
Dr Alison Cave, MHRA Chief Safety Officer said "skinny jabs are medicines licensed to treat specific medical conditions and should not be used as aesthetic or cosmetic treatments."
"They are not a quick fix to lose weight and have not been assessed to be safe when used in this way," she added.
Rebecca Reynolds, a professor of metabolic medicine at the University of Edinburgh, said there was "hardly any available data from human studies" to know if the weight loss drugs were safe in pregnancy.
"The data from animal studies suggests the potential for harm with low birth-weight and skeletal abnormalities, though more evidence is needed to assess if there are risks of taking these drugs in humans," she added.
The MHRA also warned about the impact of another weight-loss and diabetes injection, Mounjaro, on the effectiveness of oral contraception for people who are overweight.
"Those taking Mounjaro who are overweight and are using an oral form of contraception are advised to also use a non-oral form of contraception," it said.
The MHRA also added a reminder to people that these medicines "should not be bought from unregulated sellers such as beauty salons or via social media", or taken without a a prescription from a doctor.
"Not only does this expose people wanting to lose weight to serious health risks, it is also against the law to sell these medicines in this way," the statement said.
ABC/AFP