Can Ozempic really lead to unexpected pregnancies?

Ozempic has helped countless people to lose weight, and the drug has even been included in weight loss programs, including the Costco program. However, a peculiar trend has emerged among women who are taking the medication, which they’re referring to as “Ozempic babies.”

Despite being on prescription birth control alongside the weight loss drug or having histories of fertility issues, women using Ozempic have reported unexpected pregnancies. 

Ozempic and Mounjaro belong to a category of drugs known as GLP-1 receptor agonists. These drugs mimic hormones in the gut related to insulin regulation and appetite. While both are approved for treating type 2 diabetes, they also have versions authorised for weight loss. 

Ozempic contains semaglutide, and its weight-loss variant is called Wegovy. Mounjaro employs tirzepatide, which also targets another hormone called GIP, with its weight loss iteration branded as Zepbound.

Clinical trials have demonstrated that these medications can help people lose an average of 15% to 20% of their body weight. However, due to the mechanism of action of GLP-1 drugs, experts suggest that they may lead to increased fertility and warrant caution regarding their use during early pregnancy.

Does it affect birth control effectiveness?

One reason for increased fertility is that weight loss can normalise ovulation, particularly in those with conditions like PCOS or irregular menstrual cycles, according to Dr. Daniel Drucker, a professor and researcher at the University of Toronto’s Mount Sinai Hospital. 

He explained that as people lose weight while on these medications, ovulation often improves. This could potentially lead to scenarios where someone who previously had irregular periods may not realise they’re pregnant after losing weight.

Furthermore, Mounjaro and Zepbound include warnings in their prescribing information regarding potential interference with the effectiveness of birth control pills. 

This interference may occur because these drugs slow down the stomach’s food transit rate, prolonging the feeling of fullness but possibly affecting the absorption of other medications, including oral contraceptives.

Are there any risks during pregnancy?

While GLP-1 medications may enhance fertility, their safety during pregnancy remains largely unknown, as pregnant women were excluded from clinical trials conducted by the drugs’ manufacturers, Novo Nordisk and Eli Lilly. Nevertheless, ongoing studies are examining these concerns.

Novo Nordisk is conducting a registry study to evaluate the safety of Wegovy during pregnancy, with findings expected to be disclosed upon completion in 2027. Eli Lilly also intends to establish a pregnancy registry for Zepbound, which received approval at the end of the previous year.