The UK's drug safety watchdog has issued its first public warning to women taking weight loss injections, urging them to use effective contraception after receiving more than 40 reports of pregnancies among users of these medications.
The Medicines and Healthcare products Regulatory Agency (MHRA) published the alert following concerns about the safe use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs), including Mounjaro, Wegovy, Saxenda, Victoza, and Ozempic. These drugs work by mimicking hormones that promote satiety and are available through NHS specialist weight management services or private prescription.
Contraceptive Interference Concerns
The MHRA specifically highlighted that Mounjaro may reduce the effectiveness of oral contraceptives in overweight patients. Women taking this medication are advised to use additional barrier methods such as condoms alongside hormonal contraception.
"This only applies to those taking Mounjaro and is especially important for the four weeks after starting Mounjaro and after any dose increase," the MHRA stated.
The agency's data shows it has received 26 pregnancy-related reports for Mounjaro, with at least one confirmed as unintentional. Additionally, eight reports involved semaglutide (the active ingredient in Ozempic and Wegovy), and nine concerned liraglutide (found in Victoza and Saxenda), including one unintentional pregnancy.
Safety During Pregnancy
The MHRA emphasized that these medications must not be used during pregnancy, while attempting to conceive, or during breastfeeding. Women who become pregnant while using these drugs should discontinue treatment immediately.
"This is because there is not enough safety data to know whether taking the medicine could cause harm to the baby," the agency explained.
In some cases, women are advised to continue contraception for up to two months after stopping the medication before attempting pregnancy.
"Ozempic Baby Boom" Phenomenon
The warning follows reports of a "baby boom" linked to these injections, with women sharing experiences online of unexpected "Ozempic babies" despite using contraception. This phenomenon has raised concerns about potential interactions between weight loss medications and contraceptive methods.
Dr. Alison Cave, MHRA chief safety officer, emphasized that these are prescription medications for specific medical conditions. "Skinny jabs are medicines licensed to treat specific medical conditions and should not be used as aesthetic or cosmetic treatments," she said. "They are not a quick fix to lose weight and have not been assessed to be safe when used in this way."
Additional Safety Reminders
The MHRA also reminded patients about the risk of acute pancreatitis, an uncommon but serious side effect. The main symptom is severe stomach pain that radiates to the back and persists, requiring immediate medical attention.
The agency warned against purchasing these medications from unregulated sources such as beauty salons or social media platforms, urging patients to report suspected counterfeit products through the MHRA Yellow Card scheme.
Jasmine Shah, medication safety officer at the National Pharmacy Association, noted the unprecedented demand for these treatments. "Community pharmacies have been experiencing unprecedented levels of interest for weight loss injections," she said. "It is therefore important that regulations and guidance keep pace with this demand and that patient safety is put at the heart of everything we do."
