GLP-1 Medicines and Pregnancy: What to Know

Medicines such as semaglutide, liraglutide and tirzepatide can improve blood-glucose control and support substantial weight loss. But pregnancy is one situation in which the evidence remains limited: these medicines are not approved for use during pregnancy, and weight loss is not recommended while pregnant.

That does not mean an accidental early exposure proves that something has gone wrong. It means the safest next step is a prompt, calm conversation with the clinician who prescribed the medicine and the clinician providing pregnancy care.

What the human studies actually show

Most pregnancy data come from people who became pregnant unexpectedly and stopped treatment early. In a 2024 prospective study, researchers followed 168 pregnancies exposed to a GLP-1 medicine in the first trimester. Major birth defects occurred in 3 of 117 evaluable exposed pregnancies (2.6%), compared with 2.3% in a diabetes comparison group and 3.9% in an overweight or obesity comparison group.

Those results are reassuring, but they do not prove safety. The study was too small to detect rare problems, most participants stopped treatment at a median of five weeks, and it could not answer questions about exposure later in pregnancy or long-term child development.

A much larger multinational study examined 938 infants with periconceptional GLP-1 exposure among pregnancies affected by type 2 diabetes. After adjustment, the risk of major congenital malformations was not substantially higher than with insulin. However, the analysis included live births only and could not fully account for differences in diabetes control, obesity or why a particular medicine was prescribed.

Animal studies have reported impaired fetal growth and developmental changes with some GLP-1 medicines, sometimes alongside reduced maternal food intake and weight. This evidence, combined with the gaps in human data, is why product information advises avoiding these drugs during pregnancy.

Planning pregnancy while taking a GLP-1 medicine

Do not simply stop a diabetes medicine without a plan. High blood glucose itself can increase pregnancy risks, so a clinician may need to change treatment and confirm that glucose is well controlled before conception.

The appropriate stop date depends on the exact product. Semaglutide prescribing information recommends stopping at least two months before a planned pregnancy because it remains in the body for weeks. Other medicines have different pharmacology and instructions. Ask the prescriber to review the current label for your product rather than applying one medicine’s timetable to every GLP-1 drug.

Tirzepatide has an additional contraception issue. It can reduce exposure to oral hormonal contraceptives after starting treatment and after each dose increase. Current product guidance advises using a non-oral method or adding a barrier method for four weeks after initiation and for four weeks after every dose escalation.

Weight loss and improved ovulation may also make pregnancy more likely in some people whose cycles were previously irregular. A change in fertility is not guaranteed, but it is a reason to discuss contraception before treatment begins.

If you discover you are pregnant

Contact the prescriber and pregnancy-care team promptly. Tell them the medicine, dose, dates used and the first day of the last menstrual period if known. They can advise on stopping or changing treatment, review other medicines, and decide whether any additional monitoring is appropriate.

An accidental exposure is not, by itself, evidence that a pregnancy is harmed. The available observational studies have not identified a clear major-malformation signal, but the evidence is still too limited to call these medicines safe in pregnancy.

Seek urgent care for severe abdominal pain, persistent vomiting with inability to keep fluids down, fainting, heavy bleeding or other symptoms that feel serious. These symptoms have several possible causes and need individual assessment.

Planning the safest next step

GLP-1 medicines should generally be planned around pregnancy, not continued into it without specialist advice. If pregnancy occurs unexpectedly, avoid panic and obtain prompt medical guidance. The most useful consultation considers both medication exposure and the reason the medicine was prescribed, especially diabetes.

This article provides general education and does not replace individual medical advice. Medication decisions during pregnancy should be made with qualified clinicians.

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References

1. Cesta CE, et al. “Safety of GLP-1 Receptor Agonists and Other Second-Line Antidiabetics in Early Pregnancy.” JAMA Internal Medicine (2024)
2. Dao K, et al. “Use of GLP1 receptor agonists in early pregnancy and reproductive safety.” BMJ Open (2024)
3. Muller DRP, et al. “Effects of GLP-1 agonists and SGLT2 inhibitors during pregnancy and lactation on offspring outcomes.” Frontiers in Endocrinology (2023)