GLP-1s and Pregnancy

Why GLP-1s are contraindicated

Animal studies of semaglutide, tirzepatide, and liraglutide showed increased miscarriage, fetal malformations, and reduced fetal weight at doses similar to human therapeutic doses. Human pregnancy data is limited, but the FDA classifies all GLP-1s as drugs to avoid in pregnancy. The theoretical risk isn't worth taking.

Washout timing

• Semaglutide (Ozempic, Wegovy, Rybelsus): Half-life ~1 week. Fully cleared in ~5 weeks. Stop 8+ weeks before conception.
• Tirzepatide (Mounjaro, Zepbound): Half-life ~5 days. Fully cleared in ~4 weeks. Stop 6–8 weeks before conception.
• Liraglutide (Saxenda, Victoza): Half-life ~13 hours. Fully cleared in ~3 days. Stop 2+ weeks before conception.

Longer washouts are conservative — most clinicians recommend 8 weeks for semaglutide and tirzepatide as a buffer.

Fertility effects

GLP-1s themselves don't improve fertility. But the weight loss they produce can — restoring ovulatory cycles in women with PCOS, improving insulin sensitivity, and reducing pregnancy-related risks like gestational diabetes and preeclampsia. If you're planning a pregnancy and struggling to conceive, losing weight on a GLP-1 first (then stopping) is a legitimate strategy.

Contraception while on treatment

Tirzepatide (Zepbound, Mounjaro) reduces oral contraceptive absorption for 4 weeks after starting and after each dose increase. If you're on tirzepatide and not planning pregnancy, use a non-oral method: IUD, implant, injection, ring, or patch. See our GLP-1 and Birth Control guide.

If you get pregnant unexpectedly

1. Stop the injection immediately.
2. Call your OB/GYN and your prescribing clinician.
3. Enroll in the manufacturer's pregnancy registry (Novo Nordisk and Eli Lilly both maintain them) so future patients benefit from the data.
4. Standard prenatal care applies. There's no known intervention needed based on short GLP-1 exposure.

Breastfeeding

No GLP-1 has been studied in human breast milk. Manufacturer labels recommend against use while nursing. If you need to restart for medical reasons (e.g., type 2 diabetes), talk to your OB and pediatrician — the decision is patient-specific.

After delivery

You can restart a GLP-1 after weaning. Many women choose Wegovy or Zepbound to manage postpartum weight retention; discuss timing with your OB, particularly if you had gestational diabetes.

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