GLP-1 Drugs and Pregnancy: When to Stop and What to Know

GLP-1 medications are being used by millions of women of reproductive age. For anyone planning a pregnancy, or open to the possibility, understanding the guidance around these drugs is important.

The main message is clear: stop GLP-1 medication before trying to conceive, and do not use it during pregnancy or breastfeeding.

Why GLP-1 drugs should be stopped before pregnancy

GLP-1 medications have not been properly studied in human pregnancies, and they are not recommended during pregnancy. This is not because they have been proven harmful. It is because there is simply not enough safety data.

What we do know:

Animal studies showed developmental risks. Reproductive toxicity studies in rats and rabbits using semaglutide and tirzepatide showed effects including reduced fetal growth, skeletal abnormalities, and increased fetal deaths at doses relevant to human therapeutic exposure. These findings are standard triggers for pregnancy contraindications in drug labelling.

GLP-1 receptors are present in fetal tissue. GLP-1 receptors play a role in fetal organ development. Artificially activating these receptors during pregnancy could theoretically interfere with normal development, though this has not been confirmed in human data.

The precautionary principle applies. Until large-scale human pregnancy data exists, the reasonable and responsible approach is to avoid exposure.

When to stop: the timing guidance

Semaglutide labels (Ozempic, Wegovy, Rybelsus) in the US and UK advise stopping the medication at least two months before a planned pregnancy.

Why two months? Semaglutide has a half-life of approximately one week. After the last dose it stays in the circulation for about five weeks, so two months allows it to clear.

For tirzepatide (Mounjaro, Zepbound; half-life approximately 5 days), the UK label advises stopping at least one month before a planned pregnancy. The US label does not give a fixed washout period, so ask your doctor.

For oral GLP-1 medications (Wegovy pill, Rybelsus)

Oral semaglutide is the same molecule with the same half-life of about one week as the injection, so the same two-month advice applies.

Contraception while on treatment

The UK MHRA (June 2025) advises using effective contraception while taking GLP-1 medicines. Tirzepatide can make the contraceptive pill less effective: labels advise switching to a non-oral method, or adding a barrier method such as condoms, for 4 weeks after starting and for 4 weeks after each dose increase.

What happens to your body when you stop

Be prepared for a few things.

• Return of appetite. GLP-1 suppression of hunger reverses within days of stopping. Some people experience significant rebound hunger.
• Weight regain risk. Without the medication, weight may start returning. Have a plan with your doctor for managing this during the pre-conception and pregnancy period.
• Blood sugar changes (if you have diabetes). Work with your doctor to transition to pregnancy-safe diabetes management.

Can GLP-1 improve fertility before you stop?

Yes, in some cases. For women with PCOS or insulin resistance, weight loss and improved hormonal balance from GLP-1 therapy may:

• Restore more regular menstrual cycles
• Improve ovulation frequency
• Reduce androgen levels (which can interfere with conception)

This means GLP-1 therapy used beforehand, then stopped at the right time, can sometimes improve fertility prospects before conception is attempted.

Discuss this timing strategy with your gynaecologist or reproductive endocrinologist.

What to do if you discover you are pregnant while on GLP-1

1. Contact your doctor promptly: labels advise stopping the medication when pregnancy is recognised
2. Report the exposure (US): the Wegovy pregnancy registry (Novo Nordisk, 1-877-390-2760) and the Zepbound pregnancy registry (Eli Lilly, 1-800-545-5979) track outcomes in women exposed during pregnancy
3. Do not panic: there is not enough human data to show harm from early exposure, but your doctor will want to monitor the pregnancy

Breastfeeding

Advice differs by medicine and country. The UK MHRA advises not using GLP-1 medicines while breastfeeding. For semaglutide, a clinical lactation study found levels below the limit of measurement in breast milk, but the Rybelsus label says oral semaglutide is not recommended while breastfeeding because its absorption enhancer (SNAC) does pass into milk. For tirzepatide, a small study in 11 women found it undetectable or very low in breast milk after one dose; there are no data on effects on the baby, and the labels ask doctors to weigh the benefits of breastfeeding against the mother's need for the medicine. Talk to your doctor before using any GLP-1 medicine while breastfeeding.

Planning the transition

If you are on GLP-1 therapy and planning a pregnancy within the next 6–12 months, the conversation with your doctor should cover:

• The stoppage timeline (two months for semaglutide, at least one month for tirzepatide in the UK) relative to your conception plans
• Effective contraception until you stop, including a non-oral or backup method if you take tirzepatide
• Management of weight, blood sugar, or PCOS during the medication-free period
• Nutritional support during pregnancy (protein, folate, iron, DHA)
• A plan for restarting GLP-1 after breastfeeding ends

Final takeaway

Semaglutide should be stopped at least two months before trying to conceive, and tirzepatide at least one month before (UK label). These medicines are not recommended during pregnancy because of insufficient safety data and animal study findings, and use while breastfeeding needs a discussion with your doctor. Many women use GLP-1 therapy beneficially before pregnancy, particularly for PCOS and weight management, then stop at the right time. Plan the transition carefully with your doctor.

Related Articles

• Long-Term Safety of Semaglutide: What the Evidence Shows
• What Happens When You Stop Ozempic?
• GLP-1 Drugs and Fatty Liver (MASH): What to Know

Consult your healthcare provider about timing and transition planning specific to your situation.

Consult your healthcare provider before starting any medication.

Sources

• Ozempic prescribing information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/209637s025lbl.pdf
• Wegovy prescribing information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/215256s011lbl.pdf
• Zepbound prescribing information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/217806s003lbl.pdf
• Mounjaro prescribing information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/215866s034lbl.pdf
• Mounjaro UK SmPC (sections 4.5 and 4.6), emc: https://www.medicines.org.uk/emc/product/15481/smpc
• Rybelsus prescribing information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/213051s020s021lbl.pdf
• The Pharmaceutical Journal — MHRA urges women taking weight-loss drugs to use effective contraception (June 2025): https://pharmaceutical-journal.com/article/news/mhra-urges-women-taking-weight-loss-drugs-urged-to-use-effective-contraception