Ozempic and similar drugs are not recommended for use during pregnancy, but stopping the medications before conception may also come with some risks, new data shows.
The data should be interpreted as an early signal that requires further study, a researcher involved in the study told Live Science.
Little-studied population
Drugs like Ozempic, Wegovy, and Zepbound are “glucagon-like peptide-1 receptor agonists,” or GLP-1 for short. GLP-1 regulates weight and increases blood sugar through several mechanisms, such as slowing digestion and altering brain function.hunger signals.” The drugs have been linked to dozens indirect benefitsincluding a lower risk of heart attack and dangerous blood clots.
But studies in mice and rabbits show that the drugs may increase the risk of birth defects termination of pregnancy and restriction of fetal growth. “So, the current recommendation is to stop taking medications before conception,” Maya said.
This recommendation means that there is a group of women who stop using GLP-1 before pregnancy, raising the question of whether there may be any negative consequences. The general population is prescribed GLP-1 when stopping medications. accompanied by sudden weight gain and related indicators such as blood pressure, cholesterol and blood sugar levels. But these effects have not been studied during pregnancy.
“To date, only one study has examined weight gain during pregnancy following GLP-1RA use,” and “only a few” have examined the association between the drugs and other adverse pregnancy outcomes, epidemiologists say. Carolyn Sesta, Jennifer Hutcheon And Kari Johansson wrote to comment new research.
To fill this gap, researchers analyzed hundreds of singleton pregnancies born at the Mass General Brigham health care system between 2016 and 2025. They focused on about 450 pregnancies in which mothers used GLP-1 between three years before conception and 90 days after conception. About 50% stopped taking medications within six months of conception, about 34% stopped earlier and 17% stopped after conception.
Shortly before pregnancy on average BMI of these mothers, about 36 were classified as obese. The researchers compared these people treated with GLP with mothers who had never used the medication but also had a pre-pregnancy BMI of about 36. The full range of BMI in both groups ranged from from “healthy” to “severe obesity”“, with equal proportions of people in each category in each group.
Those who took and then stopped taking GLP-1 had an increased risk of preterm birth, gestational diabetes, and hypertensive disorders during pregnancysuch as gestational hypertension and preeclampsia, the analysis showed. Additionally, the group receiving GLP-1 gained more weight during pregnancy—an average of about 30 pounds (13.7 kg) compared to an average of 23 pounds (10.5 kg) in the comparison group.
And what's remarkable is that more people in the GLP-1 group had “excessive weight gain during pregnancy“, which is related to health risks for both mother and child. The amount of weight gain that is considered “excessive” varies. depending on individual BMI before pregnancyaccording to recommendations National Academy of Medicine. About 65% of the GLP group had “excessive” weight gain, compared with 49% of the comparison group.
In the treated group, timing of GLP-1 arrest did not appear to have much effect on the results. “I think we expected more pronounced changes, but our results were very similar,” Maya said. It is possible that excess weight contributed to other observed pregnancy outcomes, but current data cannot demonstrate this for certain, she noted.
Questions remain
One significant limitation of the study was that the team compared people taking GLP-1 with people of similar body weight who had never taken the drugs. In other words, the researchers looked at the treatment group only after they had been exposed to GLP-1, when their BMI had likely dropped below their pre-drug weight, the commenters noted.
In the future, Maya says, the researchers also want to take into account people's pre-GLP weights and find a comparison group with a comparable baseline BMI. This data, which they are now working to collect, will help contextualize whether there are any benefits to using weight loss medications before conception, even if you have to stop taking the medications during pregnancy.
The commenters added that some of the new study's findings appear to contradict other studies. For example, some studies have linked Use of GLP-1 To below risk of hypertensive disorders of pregnancy. But this may be because the previous studies included a higher proportion of people prescribed GLP-1 for diabetes, while the new study focused on people who were specifically taking anti-obesity drugs.
Like the new study, this previous work compared GLP-1 users to “women with a similar BMI at the start of pregnancy but without a history of GLP-1RA use,” the commenters added. This may be common to all studies due to the fact that databases are “insufficiently available” for patients' pre-treatment BMI, and because it is then difficult to link this BMI data to prescriptions and pregnancy records.
But these data gaps further highlight the need to study this population because there are currently “limited or no clinical recommendations” for the use of GLP-1 before conception, the commenters wrote. A new study published Monday (November 24) in the journal JAMAis beginning to close the gap, but more research is needed to understand the pros and cons of the drugs for people planning to conceive.
“It is critical that we strive to generate the evidence needed to both inform obstetric care and guide treatment decisions,” the commenters concluded.
As is common in drug studies, the original GLP-1 trials excluded people who said they were planning to conceive, but this population is still using these medications. “That’s how this study unfolds,” Maya said, “and then little by little we come in and advocate for some of these vulnerable groups that weren’t included in the original studies.”
This article is for informational purposes only and is not intended to provide medical advice.
