GLP-1 and pregnancy

Why GLP-1 is contraindicated during pregnancy

GLP-1 receptor agonists such as semaglutide (Ozempic, Wegovy, Rybelsus), tirzepatide (Mounjaro) and liraglutide (Saxenda) are all contraindicated during pregnancy according to the EMA product information. The reason is twofold: there are insufficient safety studies in pregnant women, and in animal studies developmental abnormalities and lower birth weight were observed at high doses.

In addition, GLP-1 causes weight loss that can be unfavourable during pregnancy. The nutritional needs of the foetus are in fact increased, and too low a calorie intake can lead to growth restriction. The effect of GLP-1 on gastric emptying can also intensify pregnancy nausea to an unbearable level.

There are now some observational studies in women who were unintentionally exposed to GLP-1 at an early stage. The most recent meta-analysis (Cesta et al., NEJM 2024) showed no increased risk of major congenital abnormalities — which is reassuring for women who accidentally became pregnant while using it. But this does not change the advice to actively avoid GLP-1 during pregnancy.

How long in advance to stop

The washout period is based on the half-life of the medicine — the time after which half of it has left the body. After 5 half-lives practically all of it is gone. The official washout periods are based on that calculation plus a safety margin.

Semaglutide (Ozempic, Wegovy, Rybelsus): half-life ~1 week. Stop at least 2 months before planned conception. For Rybelsus (oral) this is also 2 months despite the oral administration — the active substance that ends up in the blood is identical.

Tirzepatide (Mounjaro): half-life ~5 days. Stop at least 2 months before planned conception, the same advice as for semaglutide.

Liraglutide (Saxenda): half-life ~13 hours. Stop at least 1 month before conception. Because of the short half-life, liraglutide leaves the body sooner in practice.

For women with an irregular menstrual cycle or who are doing fertility monitoring: stop when you actively start trying to become pregnant, not when you consciously plan it.

Accidentally pregnant while using GLP-1

Stop the injection or tablet immediately if you suspect pregnancy. Take a pregnancy test and make an appointment with your GP or midwife as soon as possible. Actively mention that you used GLP-1 medication until recently and the exact date of the last dose.

Early exposure to GLP-1 in the first 2-4 weeks after conception has not been associated with an increased risk of congenital abnormalities in observational studies (Cesta et al., 2024, n=938). So it is not a reason to terminate the pregnancy — it is a reason to plan early check-ups with the midwife or gynaecologist.

However, the weight-loss phase you went through earlier can be unfavourable for the course of the pregnancy, especially if your BMI is now in the normal or lower range. A dietitian with experience in pregnancy can help to meet the nutritional needs of mother and child properly.

Contraception during GLP-1

GLP-1 medication has no contraceptive effect — a common misconception. If you are sexually active and do not wish to become pregnant, adequate contraception is essential during use.

A specific point of attention is the oral pill. GLP-1 slows gastric emptying, which can temporarily make the absorption of oral contraception less predictable in the first 4-8 weeks after a dose increase. For Mounjaro, the manufacturer explicitly advises using additional contraception (condom) for 4 weeks at every dose step.

Non-oral contraception such as the hormonal IUD (Mirena, Kyleena), the contraceptive injection (Depo-Provera), the implant (Implanon) or the copper IUD is not affected by GLP-1. For women on a GLP-1 programme, one of these methods is more reliable in practice.

GLP-1 as a stepping stone to pregnancy (PCOS, obesity)

In women with excess weight or polycystic ovary syndrome (PCOS), weight loss of 5-10% can restore normal ovulation and considerably increase the chance of natural pregnancy. GLP-1 medication is an effective tool to achieve that weight loss, provided it is planned in the preconception phase.

A sensible plan for women with obesity who wish to conceive: start GLP-1 under the supervision of a doctor, work towards a target weight (often a BMI of 25-30 as a realistic interim goal), then stop at least 2 months before you actively try to become pregnant, start folic acid 400-800 micrograms per day during that washout period and ensure adequate vitamin D.

For women with PCOS and insulin resistance, metformin can play an additional role during and after the GLP-1 washout phase. Metformin is permitted during pregnancy and is associated with a lower risk of pregnancy complications in women with PCOS.

GLP-1 and IVF/ICSI

GLP-1 must not be used during an IVF or ICSI cycle. The medication must have been stopped at least 2 months before the start of hormonal stimulation. This is the practice at all reputable fertility clinics in the Netherlands.

However, prior weight loss with GLP-1 can considerably improve IVF outcomes in women with obesity. Studies show that a BMI reduction of 5 points before conception is associated with higher implantation rates and lower miscarriage rates. So plan: a GLP-1 programme of 6-12 months, then a 2-month washout period, then start the IVF process.

Men who use GLP-1 and whose partner is trying to become pregnant: there is no contraindication here. GLP-1 is not detected in semen and is not teratogenic via the male side.

Practical advice if you wish to conceive

Actively discuss any wish to have children at every intake — even if it is still several years away. That way we can structure the treatment plan strategically: weight-loss phase, stabilisation phase, and a controlled washout period before pregnancy.

At Go Leaner, our BIG-registered doctors never prescribe GLP-1 to women who are actively trying to become pregnant or who want to start IVF/ICSI within 3 months. If in doubt, we refer to a fertility doctor for multidisciplinary consultation.

GLP-1 is also contraindicated during breastfeeding — see our separate article on GLP-1 and breastfeeding for the specific periods and alternatives.