Trying to get pregnant? Here's what you need to know about Mounjaro

Is Mounjaro safe to take when you're trying for a baby?

No, and that's the clear, consistent position of the prescribing guidance. Mounjaro's licence and its Summary of Product Characteristics both state that it should not be used during pregnancy or by women who are trying to conceive. The NHS England guidance on weight-management injections is direct on this point: effective contraception is required throughout treatment, and treatment should be stopped before a planned pregnancy.

The reason the guidance extends to the trying-to-conceive phase, rather than just pregnancy itself, relates to two things. First, there is simply not enough safety data from human pregnancies to know whether tirzepatide poses a risk to a developing baby. Second, the medicine has a wash-out period (the time it takes to clear your system) and the guidance recommends stopping in advance of conception to allow for this. Your prescriber can advise on the appropriate gap based on the dose you're on and how long you've been taking it.

If you're currently on Mounjaro and thinking about starting a family in the coming months, the right step is to raise this with your GP or the prescriber managing your treatment. Don't stop abruptly without a plan; a prescriber can help you wind down safely and talk through next steps for managing your weight in the interim. You can read more about whether it is safe to take Mounjaro when pregnant on our dedicated Mounjaro and trying to get pregnant page, which also covers the relationship between the medicine and fertility.

What happens to the contraceptive pill when you're on Mounjaro?

This catches a lot of people off guard, and it's worth understanding clearly. Because Mounjaro slows gastric emptying (the rate at which your stomach moves food and other substances into your small intestine) it can affect how much of an oral contraceptive pill is absorbed into your bloodstream. The MHRA advises that women using the pill should add a non-oral method of contraception, such as condoms, for the first four weeks of starting Mounjaro and for four weeks after each dose increase.

This matters practically. If you're on a dose titration schedule, there could be several points across your treatment where you need to revert to using an additional method. A long-acting reversible contraceptive (a coil or implant) avoids this issue entirely, because it doesn't rely on gut absorption. The NHS Inform Scotland guidance on weight-loss medication covers contraceptive interactions in straightforward terms if you'd like to read the detail alongside your own prescriber's advice.

There is no equivalent evidence of the same effect with semaglutide (Wegovy), though contraception guidance still applies. If you're mid-treatment and uncertain whether your contraceptive method is affected, that's a conversation to have with your GP or pharmacist before your next dose goes in the fridge.

Can Mounjaro affect fertility itself, and what about getting pregnant after stopping?

There's a separate but related question many people ask: does Mounjaro affect your ability to get pregnant at all? The honest answer is that the research here is still developing. Some evidence suggests that significant weight loss (of the kind Mounjaro can support) may itself improve fertility in people with conditions such as PCOS, where excess weight plays a role in hormonal disruption. That's a positive effect of the underlying treatment, not of the medicine acting directly on fertility.

On the other hand, there are reports that GLP-1 medicines may make oral contraceptives less effective (covered above), which has led to some unintended pregnancies in people who weren't aware of the interaction. This is one of the reasons the guidance on contraception during treatment is taken seriously. If you're wondering whether you can get pregnant while on Mounjaro, our dedicated page looks at what the current evidence says, including the unintended-pregnancy angle and what's known about conception during treatment. Our page on whether you can get pregnant on Mounjaro covers the unintended-pregnancy angle in more detail, including what the current evidence says about conception during treatment.

As for what happens after you stop, weight-loss medicines don't permanently alter your fertility, and the wash-out period is finite. Many people go on to conceive without difficulty after stopping. If you want to understand the picture after treatment ends, our guide to getting pregnant after Mounjaro addresses that question directly. The most important step, whenever you're ready, is letting your clinical team know your plans so they can help you stop safely and support you from there.

How does this affect the way a prescriber approaches the consultation?

When someone comes to us who is planning a pregnancy in the near future, our prescribers approach the consultation with that in mind from the start. Mounjaro is a prescription-only medicine, and every consultation at nume is reviewed personally by a GPhC-registered Independent Prescriber, not a questionnaire algorithm. That means the context of your life, including your family plans, is part of what shapes the clinical decision.

In practice, if you're actively trying to conceive, a prescriber would not approve Mounjaro. If you're considering starting a family in the next year or so, that's a conversation rather than a yes/no, and the right outcome might be a referral back to your GP to plan a safe stopping point first. Either way, the answer you get is a considered one, and you can also find detailed information on whether Mounjaro is bad for your liver if that is something you want to explore before starting treatment. You can explore our weight-loss treatments page to understand the options available, or if you have a specific question about your situation, our support team is available seven days a week. We'd rather give you the honest answer upfront than a consultation that ends at the first clinical hurdle.