Can you take Mounjaro when pregnant?

Is Mounjaro safe to take if you're pregnant?

The direct answer is no. Mounjaro's prescribing information is clear: it should not be used during pregnancy. The concern comes from animal reproductive studies, which showed reduced foetal weight and skeletal abnormalities when tirzepatide was given at doses that produced exposures similar to those seen in people. Human pregnancy data simply do not exist yet, tirzepatide is too new, and pregnant women are excluded from clinical trials for obvious ethical reasons.

Because the risk to a developing pregnancy cannot be quantified, clinical guidance defaults to avoidance. The NHS confirms that medicines in this class are not recommended during pregnancy, and that advice applies to anyone found to be pregnant while on treatment. If you are already taking Mounjaro and discover you are pregnant, stopping promptly and speaking to your GP or midwife is the right first step. You can read the full patient-level guidance on the NHS tirzepatide medicines page.

One straightforward thing to add to your routine: if there is any chance you could be pregnant, doing a home test before your next dose takes under a minute and removes uncertainty. It is the kind of check worth building in, particularly in the first months of treatment when cycles can sometimes be disrupted.

What should you do if you find out you're pregnant on Mounjaro?

Stop taking Mounjaro as soon as you know. Do not wait for a prescriber to tell you, the medicine is not suitable and tirzepatide has a half-life long enough that it will remain in your system for some time after your last dose regardless.

Contact your GP or maternity team to let them know you were taking Mounjaro and when you stopped. They will want to know this as part of your antenatal care. If you were prescribed Mounjaro through a service like nume, our team is available seven days a week and can help you navigate the transition and notify your GP in line with good clinical practice.

There is a dedicated page covering what to do if you got pregnant on Mounjaro with more detail on the steps involved and what to expect from your antenatal appointments. The situation is not uncommon, Mounjaro can affect how the body processes hormones, and some women experience fertility changes they were not expecting.

Reporting through the MHRA's Yellow Card scheme is available if you experience any unexpected effects during or after treatment, the scheme actively collects data on medicines used in pregnancy precisely because evidence in this area is still developing.

Does Mounjaro affect fertility or contraception?

This is one of the questions our prescribers hear regularly, and the answer matters practically. Mounjaro does not carry a specific fertility warning, but weight loss itself can restore ovulation in women whose cycles had been irregular due to excess weight. That means some women become more fertile after starting treatment than they were before, which can catch people off guard.

On contraception: the NHS England guidance on weight management injections specifically notes that tirzepatide may reduce the absorption of oral contraceptives during the first four weeks of starting treatment and for four weeks after each dose increase, because the medicine slows how quickly the stomach empties. During those windows, adding a non-oral method such as condoms provides a reliable back-up. After the four-week window at a stable dose, a standard combined or progesterone-only pill is generally considered sufficient again, but this is worth discussing with your prescriber individually. You can read more about pregnancy risk while taking Mounjaro if this is something you are actively navigating.

Women using HRT alongside Mounjaro may also want to consider transdermal preparations (patches or gels) for the same absorption reason, the NHS England guidance covers this point in more detail. If you have questions about another medication alongside treatment, our prescribers can discuss this as part of your consultation; for something quite different in character, such as Mounjaro alongside epilepsy medicines, the same principle of full disclosure applies.

When can you restart Mounjaro after pregnancy or breastfeeding?

Mounjaro is not recommended during breastfeeding either. It is not known whether tirzepatide passes into breast milk in amounts that could affect a nursing infant, and in the absence of that data the guidance defaults to avoidance.

There is no fixed rule about when you can safely restart after giving birth, because it depends on whether you are breastfeeding, how your weight and health have changed, and whether Mounjaro remains the right option for you at that point. These are decisions to revisit with a prescriber when the time comes, not assumptions to make in advance. Mounjaro is only suitable for adults who meet the clinical criteria, the prescriber assesses the whole picture each time, including anything that has changed since a previous course. For context on what a new assessment involves, the weight-loss treatments page explains the consultation process.

If you are thinking about future treatment options or want to understand the full picture of Mounjaro use during pregnancy before making any decisions, reading the detail first and then speaking to a clinician is always the right order. The same goes for anyone wondering about timing and Mounjaro around a planned pregnancy, the evidence and the practical steps deserve a clear conversation, not a rushed one.