Stopping GLP-1 drugs before pregnancy linked to higher complication risks

A team of researchers at Mass General Brigham in Boston has identified a troubling bind for pregnant women with obesity: stopping GLP-1 medications before conception—as current medical guidance recommends—appears to leave them facing steeper risks of weight gain and serious pregnancy complications.

The study, published Monday in JAMA Network Open, tracked nearly 1,800 pregnancies managed within the Mass General Brigham healthcare system between 2016 and 2025. Most involved women with obesity. Researchers compared outcomes for women who had received a GLP-1 prescription within three years before conception through 90 days after it against women who had never taken the drugs during that window. The differences were substantial.

Women who discontinued GLP-1 medications prior to pregnancy gained an average of 7.2 pounds more during gestation than those who had never used the drugs. Beyond the weight itself, they faced a 32 percent higher likelihood of gaining an unhealthy amount of weight while pregnant. The metabolic and cardiovascular consequences were more severe: a 30 percent higher risk of developing gestational diabetes, a 29 percent higher risk of high blood pressure during pregnancy, and a 34 percent higher risk of delivering before term. The researchers found no meaningful differences in rates of high or low birth weight or Cesarean delivery between the groups.

The paradox at the heart of this finding reflects genuine medical uncertainty. GLP-1 medications—drugs like semaglutide and tirzepatide that were originally developed for diabetes and have become widely used for weight loss—have not been adequately studied in pregnant women. The potential risks to a developing fetus remain unclear, which is why current medical recommendations advise women to stop taking them before or during pregnancy. Yet this study suggests that stopping the drugs creates its own set of hazards, particularly for women whose weight had been controlled by the medication.

Dr. Camille Powe, the study's senior author and an endocrinologist at Massachusetts General Hospital, acknowledged the bind her team's work has exposed. "Additional studies are needed on the balance of pre-pregnancy benefits of GLP-1s with the risks associated with interrupting them for pregnancy," she said. Dr. Jacqueline Maya, the study's lead author and a pediatric endocrinologist, noted that GLP-1 use among women "has increased dramatically" in recent years, making the question of how to manage these medications around pregnancy increasingly urgent.

Because the study was retrospective—examining medical records rather than randomly assigning women to different treatment approaches—it cannot prove that stopping GLP-1 drugs directly caused the higher complication rates. It can only show that the two things occurred together. That limitation matters, but it does not erase the pattern the data revealed.

Powe framed the challenge plainly: women with obesity now face a genuine dilemma when considering whether to use a GLP-1 before attempting pregnancy. The drugs appear to help them, but the guidance says to stop. And stopping, according to this evidence, carries its own risks. "We need to do more research to find ways to help manage weight gain and reduce risks during pregnancy when stopping GLP-1 medications," she said. That research has not yet been done, leaving women and their doctors to navigate a decision with incomplete information on both sides.