Does Mounjaro affect fertility?

Many people taking Mounjaro have questions about how treatment could affect fertility, particularly if they're planning a pregnancy in the future. Whether you're hoping to start a family or simply want to understand how the medication might affect your reproductive health, it's important to separate fact from fiction.

While there's currently insufficient evidence that Mounjaro directly increases or decreases fertility, changes in weight and metabolic health can influence reproductive health. For some people who are overweight or obese, particularly those with polycystic ovary syndrome (PCOS), weight loss may improve hormonal function and ovulation and potentially increase their chances of becoming pregnant.

In this guide, we'll explore what's known, what's still being researched and explain the important considerations around contraception and pregnancy, and help you understand what to do if you're planning to start a family.

How Mounjaro can affect fertility

Although there is currently limited evidence that Mounjaro directly improves or reduces fertility, the weight loss achieved during treatment may affect reproductive health in some people. Improvements in weight, insulin resistance and hormonal balance can sometimes support more regular ovulation, particularly for those living with obesity or conditions such as PCOS.

While Mounjaro isn't a fertility treatment, improvements in weight and metabolic health may indirectly affect your chances of becoming pregnant. That’s because excess body weight can disrupt hormone levels and ovulation, making it more difficult to conceive. For some people, losing weight may help improve these processes, although the effects vary depending on individual circumstances.

Can Mounjaro improve your chances of conception?

Mounjaro isn't designed to improve fertility, and there's currently insufficient evidence that the medication directly increases your chances of conceiving.

However, weight loss may improve fertility for some people, particularly those with polycystic ovary syndrome (PCOS). Some research suggests that GLP-1 receptor agonists may improve menstrual regularity in women with PCOS. This may be associated with improvements in ovulation, although evidence is limited and the findings cannot be assumed to apply directly to Mounjaro.

It's worth remembering that these findings primarily relate to other GLP-1 medications, rather than Mounjaro specifically. Improvements in fertility aren't guaranteed, and Mounjaro shouldn't be used as fertility treatment.

Is there a link between Mounjaro and infertility?

There's currently no established evidence that Mounjaro causes infertility in humans. However, research into its long-term effects on reproductive health is ongoing.

Changes to your menstrual cycle during weight loss don't necessarily indicate a fertility problem. Significant weight changes, stress, and conditions such as PCOS can all affect menstrual regularity.

If you've noticed changes to your cycle, our guide to whether Mounjaro can stop periods explores the possible reasons and when to seek medical advice.

If you're concerned about your fertility, speak to your healthcare provider for personalised advice.

Does weight loss affect fertility?

According to the NHS, carrying excess weight can affect fertility by disrupting hormone levels and ovulation, potentially making it more difficult to become pregnant. For some people, reaching a healthier weight may improve reproductive health and increase the likelihood of conception.

However, losing weight doesn't always improve fertility. Rapid weight loss or not eating enough can also disrupt your menstrual cycle, sometimes causing periods to become irregular or stop altogether.

The aim is to make gradual, sustainable changes that support your overall health rather than focusing on weight loss alone. If you're planning a pregnancy, speak to your healthcare provider about the safest approach to managing your weight and preparing for conception.

Can you get pregnant on Mounjaro?

Yes, you can get pregnant while taking Mounjaro. The medication isn't a form of contraception and shouldn't be relied upon to prevent pregnancy.

If weight loss helps improve previously irregular ovulation, your chances of conceiving may change during treatment. This makes it important to consider contraception, even if you've previously experienced difficulties becoming pregnant.

The European Medicines Agency recommends using contraception while taking Mounjaro. If you are using Mounjaro, you should use condoms along with your pill for four weeks after you start the medicine and for four weeks after any dose increase. Alternatively, you can discuss switching to a non-oral contraceptive method with your healthcare provider.

What should I do if I get pregnant while on Mounjaro?

If you discover you're pregnant while taking Mounjaro, stop taking the medication immediately and contact your healthcare provider as soon as possible.

Mounjaro isn't recommended during pregnancy because there's limited information about its effects on developing babies. However, taking Mounjaro before realising you're pregnant doesn't automatically mean your pregnancy has been harmed.

Your healthcare provider can discuss any potential risks, and help you understand the next steps.

Is Mounjaro safe during pregnancy?

There's currently insufficient evidence to establish whether Mounjaro increases the risk of congenital conditions, sometimes called “birth defects”, in humans.

Animal studies have identified potential risks to foetal development, but it's unclear whether these findings apply to human pregnancies. Research involving pregnant people is still limited, so the safety of Mounjaro during pregnancy hasn't been established.

This uncertainty is why healthcare professionals recommend avoiding Mounjaro during pregnancy. If you've been exposed to the medication while pregnant, your healthcare provider can discuss what this means for you and whether any additional monitoring is appropriate.

When should you stop Mounjaro before pregnancy?

If you're planning to start a family, it's important to discuss your treatment with your healthcare provider before trying to conceive.

According to Mounjaro manufacturer recommendations, the treatment should generally be stopped for at least one month before a planned pregnancy. This helps ensure that the medicine has been cleared from the body before conception.

Your healthcare provider can help you plan when to stop treatment and discuss how to manage your weight or blood sugar levels safely before pregnancy.

If you're hoping to conceive in the near future, having this conversation early can help you prepare with confidence.

"Many people don't realise that weight loss can sometimes lead to more regular ovulation, particularly if excess weight or conditions such as PCOS have previously affected their fertility. While Mounjaro isn't a fertility treatment, it is important to be aware that your chances of becoming pregnant could change during treatment. If you're planning a family, speak to your healthcare team early so you can safely prepare for pregnancy and discuss when to stop treatment."

Niya MansuriPrescribing Pharmacist

Getting support throughout your treatment

Whether you're concerned about how Mounjaro might affect your fertility or you're planning to start a family, it's important to have access to reliable advice throughout your treatment.

At myBMI, our treatment plans include ongoing clinical support to help you manage your weight loss safely and sustainably. Our clinical team can answer questions about your medication, discuss potential side effects, and help you make informed decisions about your treatment. We also offer free medication to help manage certain side effects, if deemed appropriate.

For more information about what to expect during treatment, explore our guide to Mounjaro side effects.

Whatever your plans for the future, having the right support can help you feel confident about your health and the decisions you make along the way.

Sources

• Overweight and pregnant. (2023)NHS. [Accessed 3 November 2026]
• Impact of obesity on infertility in women. (2015) PubMed. [Accessed 3 November 2026]
• Effects of GLP1RAs on pregnancy rate and menstrual cyclicity in women with polycystic ovary syndrome: a meta-analysis and systematic review. (2023) PubMed [Accessed 3 November 2026]
• Missed or late periods. (2026) NHS. [Accessed 3 November 2026]
• Polycystic ovary syndrome (PCOS). (2026) NHS. [Accessed 3 November 2026]
• Trying for a baby. (date unknown) NHS. [Accessed 3 November 2026]
• Mounjaro. (2026) EMA. [Accessed 3 November 2026]