“GLP-1 RA treatment has, within the last few years, become the medication with the sharpest increase in prescription worldwide.”
That rapid rise has brought new questions, especially for women who may become pregnant while taking these drugs. Medications like semaglutide and liraglutide, originally developed for type 2 diabetes and now widely used for weight loss, are not recommended during pregnancy. But until now, there has been limited real-world evidence on what happens when exposure occurs early, often before someone knows they are pregnant.
A new study analyzing more than 750,000 pregnancies in Denmark offers a clearer picture. Researchers found that GLP-1 drugs were linked to a higher risk of preterm birth, but only in women who were taking them to manage diabetes. Among women using the same medications for weight loss, there was no increased risk of preterm birth or other major pregnancy complications after adjusting for factors like age, body weight and smoking.
“We found that these medications were associated with an increased risk of preterm birth, but the risk was only present when the medication was used for diabetes treatment, and not for weight management.”
The distinction matters. It suggests that the underlying condition, not just the medication, may be driving the risk.
After accounting for differences between groups, the researchers found that women with diabetes who used these drugs had a higher likelihood of preterm birth compared to those who did not. The increase was measured at 70% for liraglutide and 84% for semaglutide. In practical terms, that translated to an absolute risk increase of about 9% to 11%.
Importantly, this was an observational study, meaning it cannot prove cause and effect. The findings also rely on prescription records, not confirmed medication use. Still, the scale of the data and the consistency of the results provide valuable insight into a question many clinicians have struggled to answer.
“For clinicians, the study by Hviid et al (2026) may inform preconception and early pregnancy counselling.”
Independent experts say the findings help clarify an emerging pattern. The elevated risk appears tied to diabetes itself, a condition already known to increase the likelihood of pregnancy complications. That reinforces the importance of managing metabolic health before and during pregnancy, rather than focusing solely on medication exposure.
At the same time, the study does not change current guidance. GLP-1 drugs are still not considered safe to use during pregnancy, and recommendations remain to stop them before trying to conceive.
As these medications become more common, researchers say more data will be needed to fully understand their effects. For now, the takeaway is less about the drugs alone and more about the broader health context in which they are used.
This study was conducted using Danish national health registry data and published in a peer-reviewed journal. No specific external funding source was highlighted in the release.