A new study from the University of St Andrews carefully suggests weight loss drugs like Ozempic taken around pregnancy do not raise the risk of major birth defects.
Published in the American Journal of Obstetrics and Gynaecology, St Andrews researchers carried out the largest ever systematic review of more than 49,000 pregnancies over a period of twenty years exposed to GLP-1 receptor agonists.
Weight loss drugs, known as GLP-1 receptor agonists (GLP-1 RAs), including products such as Ozempic, Wegovy, and Mounjaro are increasingly used by those hoping to conceive. Their use is currently discouraged during pregnancy, as preclinical studies have shown potential risks, including major congenital malformations and adverse foetal and pregnancy outcomes.
Despite this, their rapid and effective weight loss properties have driven widespread use, particularly in women seeking to meet BMI thresholds for fertility treatments. Consequently, an increasing number of pregnancies involve inadvertent peri-conceptional exposure to these drugs.
Meta-analysis of ten cohort and observational studies showed no statistically significant association between periconceptional GLP-1 RA exposure and major adverse fetal, pregnancy, obstetric, or labor outcomes. A small but statistically significant association with renal malformations was detected. However, this observed risk for renal malformations should be interpreted with caution as it likely reflects the severity of underlying maternal disease. For example, if the group exposed to GLP-1 RAs included more women with obesity or diabetes, and both of those conditions are independently linked to kidney malformations, that could help explain the observed association.
These findings provide cautious reassurance following inadvertent exposure but do not support routine use during pregnancy, highlighting the need for robust studies with long-term follow-up.
Senior author, Dr Javier Tello from the School of Medicine at the University of St Andrews, said: "This study tackles an important clinical question amid the surge in weight-loss drug use: their effects on pregnancy. Our findings offer cautious reassurance for women who become pregnant unexpectedly while on these medications but do not endorse routine use during pregnancy."
