GLP-1 and pregnancy: washout period, conception planning, and what to do if you find out you're pregnant

The washout math

Semaglutide (Wegovy, Ozempic) has an elimination half-life of ~1 week. Five half-lives — generally considered complete elimination — is ~5 weeks. The FDA-recommended washout for planned conception is 2 months, providing a safety margin beyond pharmacokinetic clearance.

Tirzepatide (Zepbound, Mounjaro) has a shorter half-life (~5 days). Five half-lives is ~25 days. The 2026 label update aligned recommended washout at 2 months, providing similar safety margin.

Liraglutide (Saxenda, Victoza) has a much shorter half-life (~13 hours). Standard washout is shorter, but the same conservative recommendation of 2+ months before planned conception applies in practice.

Why the washout matters

GLP-1 agonists are FDA Pregnancy Category C: animal reproductive studies showed some adverse effects (skeletal abnormalities, decreased fetal growth) at supra-therapeutic doses. Human data is limited — we don't have controlled human trials in pregnancy for ethical reasons. Post-marketing observational data from accidental exposures has not shown a clear teratogenic signal but is underpowered to rule out modest risk.

Standard obstetric practice is to avoid drugs in this category during pregnancy when alternatives exist. For GLP-1s used for weight management or non-emergent T2D, the alternative is discontinuation; for T2D requiring pharmacological control, insulin replaces GLP-1s during pregnancy.

Planned conception: the timeline

12 weeks before trying to conceive: discuss the plan with both your obesity-medicine/diabetes prescriber and your OB or reproductive endocrinologist. Establish baseline metabolic parameters and a maintenance strategy.

8 weeks before: discontinue GLP-1. Start the structured nutrition + activity transition plan. Most patients regain some weight during washout; this is expected and not a failure.

2-4 weeks before: confirm metabolic parameters (fasting glucose, A1C if diabetic, lipid panel) are within obstetric-acceptable range. Start prenatal vitamins if not already.

Conception: by this point GLP-1 exposure is below pharmacokinetic detection. Routine pregnancy care follows.

Unplanned pregnancy on a GLP-1: immediate steps

Stop the medication immediately upon confirmation of pregnancy. Don't delay to 'finish a vial' or 'take one more dose to stabilize'.

Contact your obesity-medicine/diabetes prescriber and OB the same day. They'll establish a metabolic-management plan that prioritizes glycemic control via insulin (if diabetic) and nutritional adequacy.

Don't panic about past exposure. Observational data from unintentional GLP-1 exposures in early pregnancy has not shown clear elevated risk for major congenital anomalies. Your OB will order standard first-trimester screening and may order additional sonograms.

Don't try to abort an early pregnancy because of GLP-1 exposure based on internet anxiety. Discuss with a maternal-fetal medicine specialist or genetic counselor if you have concerns about exposure — they can give you actual risk numbers, not social-media speculation.

Breastfeeding considerations

GLP-1 agonists have not been studied in breastfeeding humans. They are large peptide molecules that don't cross into breast milk readily, but the FDA labels recommend either avoiding GLP-1s during breastfeeding or not breastfeeding while on them. Discuss with your prescriber and pediatrician based on your specific circumstances.