A new international review offers early, cautious reassurance for women who discover they are pregnant while taking a GLP-1 medicine such as Ozempic or Mounjaro. After pooling seven studies that included more than 43,000 women exposed to these drugs, researchers found no significant link between exposure, mostly in the first trimester, and preterm birth, stillbirth, newborn death, preeclampsia, or babies born small for their gestational age.
The analysis was published Sept. 29 in The Lancet Obstetrics, Gynaecology & Women's Health and presented at the European Association for the Study of Diabetes meeting in Milan. It does not show that the drugs are safe in pregnancy, and it does not change advice to stop them before a planned pregnancy. Women who learn they are pregnant while on one of these medicines should call the clinician who prescribes it right away.
For many women of childbearing age, an unexpected positive test while on one of these drugs brings immediate fears about a baby's development. The new data help answer that worry, but with a key limit: nearly all of the evidence comes from women with diabetes, not women using the drugs only for weight loss.
Inside the Leicester-Led Review of Exposed Pregnancies
The work was led by Professor Claire Meek of the Leicester Diabetes Research Centre and the NIHR Leicester Biomedical Research Centre in the United Kingdom. It paired a systematic review and meta-analysis with a consensus statement from 42 specialists, informed by 60 women with lived experience.
Six of the seven studies looked at exposure in the first trimester, and one looked at use in the 12 months before pregnancy. Women exposed to GLP-1 drugs were compared with women who were not. The paper covers women with type 1, type 2, or gestational diabetes, though most data came from type 2 diabetes. Public summaries treat the medicines as a class and do not report separate results for semaglutide, the ingredient in Ozempic, or tirzepatide, the ingredient in Mounjaro.
On birth defects, the authors wrote that "available evidence, predominantly in women with type 2 diabetes, suggests that there is no increase in congenital anomaly risk following first-trimester discontinuation of GLP-1s compared to no GLP-1 exposure," according to a summary of the paper. That finding applies to women who stopped the drug early in pregnancy, not to continued use.
One signal stood out. Early pregnancy loss was 31% more common among exposed women in two studies involving 41,046 participants, but those studies grouped miscarriages and planned terminations, so researchers urged caution.
"Millions of women are now using GLP-1 receptor agonists, but there remain important unanswered questions about their impact on fertility, pregnancy, and maternal and child health," Meek said in the Leicester announcement. "Women deserve clearer evidence to guide some of the most important healthcare decisions of their lives."
The research was funded by the NIHR, Diabetes UK, the European Foundation for the Study of Diabetes and the UK Medical Research Council. Meek is also supported by a Future Leaders' Award from the European Foundation for the Study of Diabetes and the Novo Nordisk Foundation.
Oxford Researcher Says the Data Do Not Prove Safety
Dr. Nerys Astbury, an associate professor of diet and obesity at the University of Oxford who reported no conflicts, told the Science Media Centre that "the conclusions go beyond what the available evidence can currently support and should be interpreted with considerable caution."
"The key message from these results is not that GLP-1 receptor agonists have been shown to be safe during pregnancy, but that there is currently insufficient evidence to determine whether first-trimester exposure increases or decreases the risk of the pregnancy outcomes examined," Astbury said. She noted that the confidence ranges for congenital anomalies, preterm birth and early pregnancy loss include the possibility of no effect, so the results show neither a clear increase nor a clear decrease in risk.
The authors acknowledge the gaps. The exact week of exposure was often poorly documented, and data on later-trimester use, breastfeeding and long-term effects in children remain extremely limited. Meek said that "current evidence is insufficient to define the benefits and risks of GLP-1RA therapy across the reproductive life course."
Label Rules on Stopping, Birth Control and Pregnancy Registries
The U.S. prescribing information has not changed. The Ozempic label, which covers adults with type 2 diabetes, tells clinicians to "discontinue OZEMPIC in women at least 2 months before a planned pregnancy due to the long washout period for semaglutide." Wegovy, the semaglutide brand used for weight loss, carries the same two-month advice.
Tirzepatide carries an extra household concern: birth control. The Mounjaro label, approved for type 2 diabetes, advises people on birth control pills to switch to a non-oral method or add a barrier method "for 4 weeks after initiation and for 4 weeks after each dose escalation." Tirzepatide slows stomach emptying, which may reduce how well the pill is absorbed. The Ozempic and Mounjaro labels say the medicines should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus.
The weight-loss version, Zepbound, is more direct. Its label states that weight loss offers no benefit in pregnancy and tells clinicians to advise patients to stop the drug once a pregnancy is recognized. It also lists a pregnancy exposure registry at 1-844-524-0039, and the Wegovy label lists a Novo Nordisk pregnancy registry contact at 1-877-390-2760.
For a woman who has just seen a positive test, the practical step is a prompt call to her prescriber and an obstetric clinician, with the date of her last dose on hand. Women with type 2 diabetes should not make changes alone, since a clinician will need a plan to keep blood sugar controlled during pregnancy.
Women who could become pregnant can ask whether their birth control still works alongside their medicine. A switch to an IUD, implant or other non-oral method can carry costs, so it is worth asking an insurer or family planning clinic what is covered.
The study team is calling for prospective studies that follow women from before conception through breastfeeding. Until those results arrive, the new review offers comfort for women facing an unplanned exposure, but it is not permission to keep taking these drugs while pregnant.
Key Questions Answered
What did the new GLP-1 pregnancy review find?
Across seven studies including more than 43,000 exposed women, mostly with type 2 diabetes, researchers found no significant link between early exposure and preterm birth, stillbirth, newborn death, preeclampsia or small-for-age babies. Early pregnancy loss was more common, but that measure mixed miscarriages with planned terminations.
Does this mean Ozempic or Mounjaro is safe during pregnancy?
No. The authors and independent scientists say the evidence is insufficient to establish safety, especially beyond the first trimester, and drug labels still advise stopping before a planned pregnancy.
I just found out I'm pregnant and I take a GLP-1 drug. What should I do?
Contact the clinician who prescribes the medicine and an obstetric provider promptly, and note when you took your last dose. Do not make medication decisions on your own, especially if you have diabetes.
How far ahead should semaglutide be stopped before trying to conceive?
The Ozempic and Wegovy labels advise stopping at least two months before a planned pregnancy because semaglutide stays in the body for a long time.
Can Mounjaro or Zepbound affect birth control pills?
Yes. Tirzepatide labels advise switching to a non-oral method or adding a barrier method for four weeks after starting and after each dose increase.
Did the study look at women using these drugs only for weight loss?
Mostly not. The review focused on women with type 1, type 2 or gestational diabetes, so the results may not fully apply to women using the drugs for weight loss alone.
Published by Medicaldaily.com
