GLP-1 Drugs and Fertility: What Patients Planning Pregnancy Need to Know

The contraindication in pregnancy: what the label says

All GLP-1 receptor agonists carry a pregnancy contraindication in their prescribing label (FDA Wegovy label, 2025):

Discontinue semaglutide/tirzepatide [at least 2 months] before a planned pregnancy due to the long half-life of the drug.

The basis for this contraindication is:

• Animal studies showing GLP-1 agonism causes fetal growth restriction and skeletal abnormalities at doses higher than those used in humans
• Inadequate safety data from human pregnancy — no controlled studies
• Fetal development during early pregnancy is vulnerable to any pharmacological interference

This is a "Category C" (US) or "not recommended" designation in most regulatory frameworks — meaning: absence of proven harm, but insufficient human data to confirm safety, plus concerning animal data.

The 2-month stopping rule for semaglutide is specific to the long half-life — semaglutide's elimination half-life is approximately 7 days, meaning it takes approximately 5 half-lives (5 weeks) to reach near-full clearance. The 2-month recommendation provides a safety margin above this.

Tirzepatide has a slightly shorter half-life (~5 days) but the same 2-month pre-conception stopping recommendation applies in most prescribing guidelines.

The fertility question before pregnancy: does GLP-1 help?

For patients with obesity, T2D, or PCOS who are trying to conceive, GLP-1 therapy during the pre-conception phase may actually improve fertility — before being discontinued.

The pathway:

Obesity and fertility: Obesity impairs fertility through multiple mechanisms — disrupted HPO (hypothalamic-pituitary-ovarian) axis, elevated oestrogen from adipose tissue aromatase, hyperinsulinaemia, and inflammation. Weight loss of even 5–10% significantly improves ovulation rates and cycle regularity in obese women.

GLP-1 therapy produces 15–21% average weight loss — substantially more than lifestyle-only intervention. For women with obesity-related anovulation, pre-conception GLP-1 therapy (followed by the 2-month stopping window before attempting pregnancy) is increasingly discussed as a fertility preparation strategy.

PCOS and fertility: PCOS is the leading cause of anovulatory infertility in women of reproductive age. GLP-1 therapy addresses the insulin resistance underlying PCOS:

• Improves menstrual regularity (via reduced hyperinsulinaemia)
• Reduces androgen levels (via weight loss and direct insulin sensitisation)
• Improves ovulation frequency
• Reduces miscarriage risk (obesity and insulin resistance are associated with early pregnancy loss)

A growing body of observational data supports GLP-1 use in PCOS patients as pre-conception preparation. No RCTs specifically address this endpoint.

T2D and fertility: Poorly controlled T2D impairs fertility and increases early pregnancy loss and congenital abnormality risk. GLP-1 therapy for T2D optimisation before conception — then stopped before the attempt — is consistent with fertility medicine best practice.

The critical timing question: when to stop

The stopping window has practical implications for patients actively trying to conceive:

Semaglutide (Wegovy/Ozempic): Stop at least 2 months before attempting conception. Practically: if you plan to start trying in month 6 of the year, stop in month 4.

Tirzepatide (Zepbound/Mounjaro): The prescribing label recommends stopping at least 2 months before conception, consistent with semaglutide.

What happens after stopping: Weight regain begins within weeks of discontinuation (see our article on weight regain after GLP-1 therapy). Some regain before the conception attempt is expected. The benefit of improved baseline weight and metabolism from pre-conception GLP-1 use persists partially even after stopping, but long-term the drug cannot be maintained through pregnancy.

If pregnancy occurs while on GLP-1: Discontinue immediately and inform your obstetrician. The data on inadvertent first-trimester GLP-1 exposure is limited to case reports and small series — no clear pattern of fetal harm has been established from inadvertent early exposure, but this should be managed in consultation with a maternal-fetal medicine specialist.

Male fertility

GLP-1 receptors are expressed in the testes and appear to influence spermatogenesis. Research on this is limited:

Potentially beneficial effects:

• Weight loss improves testosterone levels (obesity suppresses testosterone via aromatase conversion of androgens to oestrogens in adipose tissue)
• Reduced insulin resistance improves LH/FSH ratios
• Some animal studies show direct GLP-1 receptor effects on sperm motility

Potential concerns:

• GLP-1 receptors on Leydig cells — unknown net effect of pharmacological agonism on steroidogenesis in humans
• Limited human data

Current clinical guidance does not specify a pre-conception stopping window for male partners. The practical recommendation: for couples undergoing IVF or fertility workup, male partners should discuss GLP-1 use with the fertility specialist.

Oral contraceptives and GLP-1 drug interactions

GLP-1-induced gastric slowing reduces the absorption rate of oral medications. For patients on oral contraceptives (OCP) as a birth control method — whether or not they are actively trying to conceive — this is clinically relevant:

• Combined oral contraceptives containing ethinyl oestradiol may have reduced absorption when taken with GLP-1 therapy
• The FDA prescribing label for semaglutide specifically states that a back-up contraceptive method should be considered for 4 weeks after each semaglutide dose escalation step
• Non-oral contraception (IUD, injection, patch, vaginal ring, implant) is not affected by GLP-1-induced gastric slowing

Patients using GLP-1 therapy for weight management who are not currently planning pregnancy should confirm with their prescriber that their contraceptive method is adequate.

Pregnancy outcomes in patients with prior GLP-1 use

The data on pregnancy outcomes in women who took GLP-1 before conceiving is reassuring but limited:

• No signal of increased congenital anomalies in women who had GLP-1 exposure before pregnancy (but stopped in the pre-conception period)
• Retrospective analyses of IVF outcomes in PCOS patients who used GLP-1 pre-conception show improved live birth rates
• No RCT data exists on GLP-1 pre-conception strategy on pregnancy outcomes

Summary

GLP-1 receptor agonists are contraindicated during pregnancy and should be stopped at least 2 months before conception attempts. For women with obesity, PCOS, or T2D, GLP-1 therapy before this stopping window may improve fertility outcomes by reducing weight, improving insulin sensitivity, and restoring ovulation. The drug's long-term health benefits for the mother — reduced cardiometabolic risk — are also relevant context for the clinical conversation. Oral contraceptive users on GLP-1 should confirm contraceptive efficacy with their prescriber during escalation periods.

This article is queued for review by a medical doctor. It should not be used as personal medical advice.