UK health officials have issued new guidance warning that tirzepatide—sold as Mounjaro—may reduce the effectiveness of oral contraceptives and pose risks during pregnancy.
The Medicines and Healthcare products Regulatory Agency (MHRA) advised that women who are overweight and taking Mounjaro should use a second form of contraception, such as an IUD, implant, or condoms. This is especially important during the first four weeks after starting the medication or after a dose increase.
Mounjaro, used for type 2 diabetes and weight loss, may affect digestion, making it harder for oral birth control pills to be absorbed. Experts say weight loss can also increase fertility, further raising the chances of unintended pregnancy.
The MHRA also warned against using Mounjaro and similar medications—including Ozempic, Wegovy, Saxenda, and Victoza—while pregnant, breastfeeding, or trying to conceive. There’s insufficient safety data on how these drugs may affect fetal development.
The U.S. Food and Drug Administration (FDA) has issued similar recommendations, advising women to switch from oral to non-oral contraception when taking Mounjaro.
Doctors say anyone taking GLP-1 medications and concerned about pregnancy should speak with a healthcare provider about safer options.
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