The complex link between weight-loss drugs and pregnancy

 A new study highlights potential risks for individuals who stop taking weight-loss medications such as GLP-1 drugs like Ozempic before or during pregnancy, revealing higher rates of excess gestational weight gain, preterm delivery, and gestational diabetes compared with those who had not been prescribed these medications. The research analysed nearly 150,000 pregnancies between June 2016 and March 2025, providing some of the most comprehensive data yet on the intersection of obesity treatment and maternal health.

Researchers from Mass General Brigham in Boston examined medical records to assess outcomes for patients previously prescribed GLP-1 medications, commonly used to treat Type 2 diabetes and obesity. Among 448 pregnancies in individuals who had taken these drugs, 65 per cent experienced gestational weight gain above recommended levels, compared with 49 per cent among 1,344 pregnancies of individuals with similar characteristics who had not used the medications.

“People with obesity who become pregnant are in a vulnerable state, and the impact we can have in helping them is big because we are affecting two lives,” said Jacqueline Maya, a pediatric endocrinologist at Mass General Brigham and lead author of the study. She noted that research in this area has lagged despite widespread GLP-1 use and limited guidance for patients needing to stop the medications before or early in pregnancy.

Experts not involved in the study emphasised both the benefits and the complexities of the findings. Taraneh Soleymani, an associate professor of medicine at Penn State College of Medicine, said, “Obesity is a chronic disease, and when treatment stops, weight is often regained. That does not diminish the benefits these drugs have on obesity before conception.” She added that losing weight prior to pregnancy can lower the risk of gestational diabetes and hypertension, conditions that carry long-term risks for both mother and child.

The study’s limitations include reliance on prescription records rather than confirmed medication adherence, and the comparison of post-treatment weights rather than pre-treatment baselines, which could affect interpretation of the results. Nonetheless, the research underscores the importance of post-treatment support, including nutrition guidance and behavioural strategies to manage appetite and cravings.

Sandra Christensen, a nurse practitioner and obesity medicine specialist, said the findings fill a critical gap. “It really adds to the science and asks important questions about how we can improve outcomes for women and their babies,” she said. She highlighted the need to explore outcomes across different age groups, as the study focused mainly on patients in their 30s.

The results signal the need for careful monitoring and tailored support for patients discontinuing GLP-1 drugs during pregnancy, emphasising that preparation, guidance, and post-treatment care are key to promoting maternal and infant health.