The Medicines and Healthcare products Regulatory Agency (MHRA) has warned that women using GLP-1 weight-loss drugs must use effective contraception. This is because the risks these drugs pose to unborn babies are still unclear.
The warning comes amid concerns that some women in the UK may not be using GLP-1 medications safely. So far, the MHRA has received over 40 reports about pregnancies in women taking these drugs.
“These medicines must not be used during pregnancy, while trying to conceive, or while breastfeeding,” the MHRA said. It advised women who become pregnant while on these drugs to stop immediately and seek medical advice. There is not enough safety data to know if these drugs could harm a developing baby.
Avoid Buying From Unregulated Sources, MHRA Warns
The MHRA also cautioned against purchasing these drugs from unregulated sellers such as beauty salons or social media platforms.
Dr. Alison Cave, MHRA’s chief safety officer, said, “Buying medicines this way puts people at serious health risk and is illegal.” She added that weight-loss drugs should only be taken after consulting a healthcare professional.
“The only way to be sure you have a genuine GLP-1 medicine is to get it from a licensed pharmacy,” Cave emphasized.
Pharmacies Report High Demand
Jasmine Shah, medication safety officer at the National Pharmacy Association, said community pharmacies are seeing unprecedented demand for weight loss injections. She stressed the need for regulations to keep up with this growing interest.
Mounjaro May Affect Birth Control
The MHRA highlighted that Mounjaro (tirzepatide), one type of GLP-1 drug, might reduce the effectiveness of oral contraceptives in people who are overweight or obese.
Women taking Mounjaro should use a non-oral form of contraception for four weeks after starting the drug and for four weeks after any dose increase. This warning applies only to Mounjaro users.
Patients are also advised to watch for signs of acute pancreatitis.
Unclear Risks in Pregnancy
Rebecca Reynolds, professor of metabolic medicine at the University of Edinburgh, told the Science Media Centre that there is very little human data on the safety of these drugs during pregnancy.
Animal studies suggest possible risks such as low birthweight and bone abnormalities. However, more research is needed to know if these risks apply to humans.
Dr. Bassel Wattar, consultant obstetrician and gynaecologist, supported the MHRA’s caution. He noted animal studies show a risk of fetal malformation when GLP-1 drugs are taken during pregnancy, but human data is limited.
On the other hand, Dr. Caroline Ovadia, senior clinical lecturer in obstetrics, said existing human studies have not found clear evidence of harm.
Online Buyers May Miss Important Safety Advice
Experts warned that although direct proof linking GLP-1 drugs to contraceptive failure is limited, the large number of users means even a small risk is important for public health.
Professor Ying Cheong, consultant in reproductive medicine, explained that side effects like vomiting and diarrhea could reduce how well oral contraceptives work. This could increase the chance of unintended pregnancy.
Reynolds also pointed out, “Many people buy these weight-loss drugs online and may not get essential advice about contraception.”
“These are not harmless lifestyle drugs,” Cheong said. “The public needs to know that these medicines require proper medical supervision to avoid unintended harm, especially to reproductive health.”
