GLP-1 medications and pregnancy: what the evidence actually shows

If you are pregnant, think you may be pregnant, or are planning a pregnancy, contact the prescribing clinician promptly. This article is not individualized medical advice.

• Weight loss offers no benefit to a pregnant patient and may cause fetal harm, so both Wegovy and Zepbound labels instruct discontinuation when pregnancy is recognized for weight-related indications.
• Because of semaglutide's long half-life, Wegovy's label advises stopping at least two months before a planned pregnancy for weight reduction or cardiovascular risk reduction, while Zepbound's label does not give a preconception stop window.
• Animal studies for both drugs showed fetal abnormalities at clinically relevant exposures, but human data are too limited to confirm or rule out these risks in people.

For Wegovy, the label states that available pharmacovigilance data and clinical trial data in pregnant patients are insufficient to establish a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. For Zepbound, the label similarly notes that available data with tirzepatide in pregnant patients are insufficient to evaluate for a drug-related risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes.

Both manufacturers maintain pregnancy exposure registries that monitor outcomes. Pregnant women exposed to Wegovy and healthcare providers are encouraged to contact Novo Nordisk at 1-877-390-2760 or visit www.wegovypregnancyregistry.com. For Zepbound, pregnant patients exposed to the medicine and healthcare providers are encouraged to register by calling 1-844-524-0039 or emailing MILEregistry@thermofisher.com, and can learn more at https://pregnancyregistry.lilly.com/zepbound.

Animal reproduction studies with both medicines found potential risks. For Wegovy, studies in pregnant rats showed embryofetal mortality, structural abnormalities, and alterations to growth at clinically relevant exposures at the maximum recommended human dose of the subcutaneous injection. Studies in pregnant rabbits and cynomolgus monkeys showed early pregnancy losses and structural abnormalities. Zepbound's animal data also showed fetal growth reductions and fetal abnormalities in rats, and fetal growth reductions in rabbits, at clinically relevant exposures. However, the U.S. general population background risk of major birth defects is 2% to 4%, and miscarriage is 15% to 20% in clinically recognized pregnancies. The background risk for the indicated populations is unknown, and for Zepbound the label notes that the estimated background risk of major birth defects and miscarriage for the indicated population is increased compared with the general population.

The Wegovy label instructs patients using the medicine for cardiovascular risk reduction or weight reduction to discontinue Wegovy when pregnancy is recognized. For patients using Wegovy for noncirrhotic metabolic dysfunction-associated steatohepatitis with moderate to advanced liver fibrosis, the instruction is different: use during pregnancy only if the potential benefit justifies the potential risk to the fetus.

The Zepbound label states that weight loss is not recommended during pregnancy and instructs patients to discontinue Zepbound when a pregnancy is recognized.

Both labels are explicit: weight loss offers no benefit to a pregnant patient and may cause fetal harm. Appropriate weight gain based on pre-pregnancy weight is currently recommended for all pregnant patients, including those who already have overweight or obesity, because of the obligatory weight gain that occurs in maternal tissues during pregnancy.

The Wegovy label also notes there may be risks to the mother and fetus related to underlying MASH with advanced liver fibrosis, such as increased risks of gestational diabetes, hypertensive complications, preterm birth, and postpartum hemorrhage. The effect of Wegovy on these risks is unknown.

For Wegovy used for cardiovascular risk reduction or weight reduction, or for MASH where the potential risk outweighs the potential benefit, the label advises discontinuing the medicine at least two months before a planned pregnancy because of the long half-life of semaglutide. This two-month window is specific to semaglutide products and does not appear in the Zepbound label. Do not apply it to all GLP-1 medicines.

If you are planning a pregnancy, ask the prescriber when to stop the specific product and how diabetes, weight, cardiovascular, or liver care will be managed during the transition.

The Zepbound label warns that use of Zepbound may reduce the efficacy of oral hormonal contraceptives due to delayed gastric emptying. This delay is largest after the first dose and diminishes over time. The label advises patients using oral hormonal contraceptives to switch to a non-oral contraceptive method, or add a barrier method of contraception for 4 weeks after initiation with Zepbound and for 4 weeks after each dose escalation.

Wegovy's label carries no similar warning for oral contraceptives, but notes that Wegovy delays gastric emptying and may impact absorption of concomitantly administered oral medications.

Regarding breastfeeding, there are no data on the presence of subcutaneously administered semaglutide or its metabolites in human milk for Wegovy injection. For Zepbound, a single-dose clinical lactation study found the concentration of tirzepatide in breast milk to be either undetectable or low compared to the maternal administered dose, but there are no available data on the effects on the breastfed infant or on milk production for either product.

People with pre-gestational type 2 diabetes face elevated baseline risks for congenital malformations regardless of which medication they take. Good blood sugar control around the time of conception is critical, because malformation risk rises with maternal blood sugar levels.

Insulin has traditionally been the guideline-recommended treatment for type 2 diabetes in people who are planning pregnancy or are already pregnant. The fact that a large cohort study of 51,826 infants born to women with type 2 diabetes showed comparable malformation rates between GLP-1 receptor agonist users and insulin users (8.3% versus 7.8%) is reassuring, but the study's authors describe the estimates as imprecise and say confirmation is needed.

• Confirm the product-specific instruction: Ask whether your medication is Wegovy or Zepbound and for which indication, because instructions differ.
• Preconception planning: If you are planning pregnancy, ask when to stop the medicine and how underlying conditions will be managed during the transition.
• Contraception: If you are using oral hormonal contraceptives and Zepbound, discuss the need for a non-oral or barrier method during initiation and dose changes.
• If you are already pregnant: Contact your prescribing clinician immediately; do not restart, continue, or replace treatment without a plan.
• Exposure registry: Ask about reporting your experience to the pregnancy exposure registry to help build the human evidence base.

I found out I was pregnant while taking semaglutide. Should I be worried?

Based on the human data available so far, accidental first-trimester exposure does not appear to be associated with a dramatically elevated risk of major birth defects. For weight reduction, the Wegovy label says to stop the medicine when pregnancy is recognized, so contact your provider as soon as possible. They can review your specific exposure timing, discuss whether any additional monitoring is appropriate, and help you interpret what the evidence means for your situation. The available data offer some reassurance, but the study's sample size was limited, and larger studies are needed.

Why does the Wegovy label say to stop two months before pregnancy, not just when I get a positive test?

Semaglutide has a long half-life, meaning drug levels remain in the body for weeks after the last dose. Stopping only when you see a positive test would mean the drug is still active during early pregnancy. The two-month window is intended to allow drug levels to clear before conception occurs.

Are GLP-1 medications safe to use while breastfeeding?

This is a separate question from pregnancy safety. The evidence base for breastfeeding is similarly limited. If you are breastfeeding or planning to, ask your provider specifically about this, as it involves different considerations.

What should I use instead of a GLP-1 medication to manage my diabetes during pregnancy?

Insulin has traditionally been the guideline-recommended treatment for type 2 diabetes during pregnancy. Transitioning from a GLP-1 medication to insulin is a clinical decision that should be made with your healthcare team, ideally before you try to conceive.

Are compounded GLP-1 products safer or different during pregnancy?

No. Compounded GLP-1 products are not FDA approved, and the FDA does not review them for safety, effectiveness, or quality before they are marketed.

If animal studies showed problems, why isn't this considered a definitive danger?

Human observational data have not confirmed the same pattern of malformations seen in animals. At the same time, limited human data that have not yet detected a signal do not constitute proof of safety. The animal findings are a legitimate reason for caution, and the human data so far offer some reassurance. Both remain true simultaneously.

Will the guidance on GLP-1 medications and pregnancy change as more research comes out?

It may. Pregnancy registries monitor outcomes, and continued monitoring is expected to give more precise estimates. Current recommendations should be treated as a starting point for discussion with your provider, not a permanent final word.