Does Semaglutide Affect Female Fertility?

What the clinical evidence says about semaglutide and ovarian function

The STEP 1 trial, published in the New England Journal of Medicine, enrolled 1,961 adults and tracked a wide range of outcomes over 68 weeks at the 2.4 mg maintenance dose. Reproductive-specific harm in women was not among the signals that emerged. No robust clinical trial to date has identified semaglutide as a direct cause of reduced female fertility, disrupted ovarian reserve, or long-term menstrual irregularity attributable to the medicine itself rather than the weight changes it produces. That is a meaningful absence, though it comes with an honest caveat: reproductive outcomes were not the primary endpoint of STEP 1, and dedicated fertility trials have not been conducted.

What the evidence does document is a secondary effect that catches some women off guard. Obesity can suppress ovulation through hormonal pathways involving leptin, androgen levels and insulin resistance. Rapid, sustained weight loss can reverse some of that suppression relatively quickly. Women who had irregular or absent cycles, or who had been told their fertility was low because of their weight, may find that regular ovulation returns during treatment. The clinical picture around Wegovy and fertility more broadly covers this in more detail, including the PCOS data. The practical implication is not abstract: if you have been relying on fertility difficulties as informal contraception, that assumption needs revisiting early in treatment.

Semaglutide is also being studied in the context of PCOS specifically, where weight reduction tends to improve hormonal profiles, but that research is still maturing and no UK licence covers that indication directly. Speak with your GP or a gynaecologist if PCOS is part of your picture.

The contraception guidance, and where it differs from tirzepatide

NHS England's guidance for women on weight management injections is explicit: use effective contraception during treatment and for a period after stopping, before trying to conceive. The wash-out period is important because semaglutide, like other GLP-1 medicines, is not considered safe in pregnancy, and the timing of stopping treatment needs to be planned with a clinician.

A question our prescribers hear regularly is whether oral contraceptive pills work less well on semaglutide, the way they can on tirzepatide. The evidence here is specific: NHS England's weight management injections guidance notes that for semaglutide there is no equivalent evidence of reduced pill absorption. Women taking Mounjaro (tirzepatide) are advised to add a non-oral method during the first four weeks of treatment and for four weeks after each dose increase, because tirzepatide slows gastric emptying enough to affect pill absorption. That specific precaution applies to tirzepatide, not to Wegovy. That distinction matters if you are comparing medicines or planning to switch.

Regardless of which medicine you are taking, the reliable-contraception advice stands. Non-oral methods (patches, implants, the coil, condoms) avoid the absorption question entirely and are worth discussing with your GP or nurse.

Not recommended during pregnancy, breastfeeding or when actively trying to conceive

This is where the guidance is at its clearest, and it is worth stating plainly. Semaglutide is not recommended in pregnancy. It is not recommended while breastfeeding. It is not recommended for women who are actively trying to conceive. These are not precautionary footnotes; they reflect the position of the MHRA and the product's licensed use, supported by animal study findings and the absence of adequate human safety data in these groups. The Wegovy and pregnancy page covers the reasoning and the timing around stopping treatment in full.

If you are planning a family in the next year or two, the conversation with your prescriber or GP should happen before you start treatment, not after. A prescriber can help you think through timing: how long treatment might run, a realistic stopping point, and the wash-out period before conception is appropriate. That planning is genuinely straightforward when it happens early. Stopping without a plan, on the other hand, can mean losing the benefits of treatment at a point when your health would benefit from them most.

If you are already on treatment and your circumstances have changed (a positive pregnancy test, a decision to stop contraception) contact your prescriber promptly. Our support team is available seven days a week.

Making a decision that fits your life

For women of reproductive age, the question of whether semaglutide affects female fertility is really several questions at once: will it harm my existing fertility? Might it restore fertility I had lost? How do I plan contraception? And what happens when I want to conceive? The honest answer to each is more nuanced than a simple yes or no, which is exactly why a GPhC-registered Independent Prescriber reads every consultation personally rather than letting software make that call.

Worth knowing: because Wegovy is taken once weekly, many women find it straightforward to build the injection into a fixed routine. Keep your pen in the fridge door rather than the back of the shelf, next to something you reach for on the same day each week, and the habit tends to stick.

If you want to explore whether treatment is appropriate for your situation, start a free consultation with our prescribers. If you are curious how semaglutide compares across other health dimensions, our pages on semaglutide and cardiovascular health and its effects on the liver draw on the same evidence-based approach. There is also a separate page covering semaglutide and male fertility if that is relevant to your household. And if you have questions about combining Wegovy with other medicines, our antidepressants interaction page is a useful starting point for that conversation.