GLP-1s and pregnancy: what each label says

What does each GLP-1 label say about pregnancy?

Every label says the human data are not enough to judge the risk, and that animal studies showed possible harm to the fetus^1–4. Where they differ is what to do: stop when pregnancy is recognized, or use only if the benefit justifies the risk.

The US labels give the background risk for comparison. In the US general population, 2% to 4% of recognized pregnancies have a major birth defect and 15% to 20% end in miscarriage^1,3. The Ozempic and Mounjaro labels add that with pre-existing diabetes and an HbA1c over 7%, the birth defect risk is 6% to 10%, and up to 20% to 25% with an HbA1c over 10%^2,4.

How long before getting pregnant should you stop a GLP-1?

For semaglutide (Wegovy, Ozempic), the US and UK labels both say at least 2 months before a planned pregnancy^1–2,5–6. The Wegovy label says this is "to account for the long half-life of semaglutide"¹. The Wegovy Medication Guide puts it as: "You should stop using WEGOVY 2 months before you plan to become pregnant"¹.

For tirzepatide, the UK Mounjaro SmPC says at least 1 month, "due to the long half-life of tirzepatide"⁷. The US Mounjaro and Zepbound labels don't set a time before a planned pregnancy^3–4. The MHRA's UK table gives at least 2 months for semaglutide and at least 1 month for tirzepatide⁸.

The Ozempic Medication Guide also says to talk to your provider "about the best way to control your blood sugar if you plan to become pregnant or while you are pregnant"². Planning a pregnancy is a conversation to have with your prescriber.

What if you get pregnant while taking Wegovy, Ozempic or Mounjaro?

The US labels say to tell your healthcare provider^1–4. Wegovy and Zepbound are the clearest: stop the medicine when pregnancy is recognized^1,3. In the UK, the SmPCs for Wegovy and Ozempic say semaglutide should be stopped if pregnancy occurs^5–6, and the MHRA says to speak to a healthcare professional straight away⁸.

• Why the labels worry: in rats, semaglutide caused embryo deaths, structural abnormalities and growth changes. In rabbits and monkeys there were early pregnancy losses and abnormalities. These happened alongside marked weight loss in the mothers¹. Tirzepatide caused smaller fetuses and abnormalities in rats, and smaller fetuses in rabbits³.
• Weight gain in pregnancy: the Wegovy and Zepbound labels say appropriate weight gain is recommended for all pregnant patients, including those with overweight or obesity^1,3.
• Pregnancy registries: in the US, Wegovy has one at 1-877-390-2760 and Zepbound at 1-844-524-0039^1,3. In the UK, the Wegovy SmPC asks for any pregnancy to be reported to the Novo Nordisk UK pregnancy registry⁵.

Can you take a GLP-1 while breastfeeding?

The labels disagree. The US labels for Wegovy injection, Ozempic, Zepbound and Mounjaro ask your provider to weigh the benefits of breastfeeding against your need for the medicine^1–4. The UK semaglutide SmPCs say not to use it while breastfeeding^5–6, and the UK Mounjaro SmPC says tirzepatide could be considered⁷.

In that tirzepatide study, the total amount found in milk over 28 days was less than 0.02% of the mother's dose^3–4. The UK SmPC adds that it isn't known whether eating less on tirzepatide changes the nutrients in breast milk⁷. The MHRA's general guidance says GLP-1 medicines should not be taken by people who are breastfeeding⁸. With advice this mixed, the choice is one to make with your prescriber or pharmacist.

What does the MHRA say about GLP-1s and pregnancy in the UK?

The MHRA says GLP-1 medicines "should not be taken during pregnancy or just before trying to get pregnant", because there isn't enough safety data⁸. It advises contraception, or avoiding sex where you could get pregnant, while taking them and for the wash-out time after⁸.

The UK SmPCs for Wegovy and Ozempic also say women who could get pregnant are recommended to use contraception^5–6. The Mounjaro SmPC says tirzepatide is not recommended in women who could get pregnant and aren't using contraception⁷. The effect of semaglutide or tirzepatide on human fertility is unknown^5,7.