Do weight loss drugs affect fertility treatment?

Wegovy, Ozempic, Rybelsus, and Mounjaro are dominating headlines and social media feeds - and not just in conversations about weight loss. More and more people are asking how these medications might affect fertility, especially those preparing for IVF or trying to conceive naturally. 

While interest in these drugs is growing, especially online, it’s important to understand the clinical guidance, the gaps in research, and the risks of using them without support from a fertility specialist. 

• Why weight loss drugs are in the spotlight 
  
• The fertility conversation 
• Stopping weight loss medication before fertility treatment 
• Online prescriptions and safety concerns 
• What we still don’t know 
• What this means if you're trying to conceive 
  

Why weight loss drugs are in the spotlight 

Ozempic, Rybelsus, Wegovy (semaglutides) and Mounjaro (tirzepatide) were originally developed to manage type 2 diabetes, but their effects on weight loss have led to a wider rollout in the UK for people living with obesity or weight-related health conditions. 

All four medications work by mimicking hormones that regulate hunger and digestion - helping you to feel fuller for longer and reducing your overall appetite. The result for many is a gradual, sustained drop in weight. Mounjaro also acts on a second hormone pathway, and early trials suggest it may produce even greater weight loss than semaglutide alone. 

With thousands now accessing these drugs via private clinics or online providers, often without in-person follow-up, questions about their impact on fertility and pregnancy are becoming more urgent. 

The fertility conversation 

For people with higher BMIs, modest weight loss can improve ovulation, menstrual regularity, and the chances of conception - particularly in those with polycystic ovary syndrome (PCOS). That’s why these drugs are sometimes seen as a tool to improve fertility outcomes. 

But here's where caution is needed. 

• These medications are not licensed or approved for use during fertility treatment. 

• They haven’t been tested in people who are pregnant or actively trying to conceive. 
• Some early studies in animals have shown a potential risk to foetal development, which is why current advice is to avoid use in pregnancy and stop treatment well in advance of trying to conceive. 
  

Stopping weight loss medication before fertility treatment 

If you’re taking a GLP-1 or GIP/GLP-1 receptor agonist (like Wegovy, Ozempic, Rybelsus, or Mounjaro), the advice from the Medicines and Healthcare products agency (MHRA), is clear: 

You should stop the medication before starting fertility treatment or trying to conceive. 

For most people, that means coming off the drug at least eight weeks before starting IVF or attempting pregnancy.  

The current guidance states that this should be 1 month for Mounjaro, and at least 2 months for Wegovy, Ozempic, and Rybelsus*. 

This gives your body time to clear the medication (known as the ‘wash out’ window) and allows fertility specialists to accurately assess your natural hormone levels, ovulation patterns, and treatment response. 

Online prescriptions and safety concerns 

While the rise in online prescribing has made access easier, it also raises concerns about continuity of care, especially if you’re also planning fertility treatment. Without face-to-face assessments, it’s possible to miss: 

• Important discussions about when to stop the drug before pregnancy 

• Underlying conditions like thyroid imbalance or insulin resistance 

• The need for a more gradual, supported weight management plan 

If you’re considering or already using one of these medications and thinking about starting fertility treatment, it’s important to tell your care team as early as possible. Not only to ensure the safety of you and any potential pregnancy, but to make sure your treatment plan is truly tailored to you. 

What we still don’t know 

Perhaps the biggest issue is that long-term studies on these drugs and fertility are lacking. We don’t yet know how they might affect: 

• Egg quality or endometrial health 

• Embryo implantation 

• Pregnancy outcomes, especially in early gestation 

Until more evidence becomes available, the safest approach is to treat these medications as incompatible with active fertility treatment or pregnancy. 

What this means if you're trying to conceive 

There’s no denying that Wegovy, Ozempic, Rybelsus, and Mounjaro are changing the landscape of weight management. For some, they may be a helpful part of a longer-term plan to support fertility. But timing, clinical oversight and safety all matter, especially if you’re planning IVF or trying naturally. 

Right now, the guidance is simple: these drugs should not be used during fertility treatment or pregnancy. If you’re taking them, you’ll need to stop taking them at least eight weeks before starting fertility drugs or attempting to conceive*. 

Any decisions about starting or stopping should be made with support from a qualified clinician who understands your fertility goals. 

If you’re using a weight loss medication and thinking about starting treatment, we’re here to help you work out the safest way forward. Get in touch with us by calling our patient enquiry team or using your companion app. We’ll talk through your options, answer your questions and make sure you feel fully supported throughout your journey. 

*At the time of writing (July 2025) this was the guidance provided by the Medicines and Healthcare products agency (MHRA).