Can you take Mounjaro while pregnant?

Jump to: UK clinical guidance | What the evidence says | Stopping Mounjaro before conception | Mounjaro and contraception | If you get pregnant on Mounjaro | Mounjaro and breastfeeding | Restarting after pregnancy | Fertility, PCOS, and IVF | Mounjaro vs Wegovy in pregnancy | When to speak to your GP | FAQs | Take home message

Mounjaro shouldn’t be used during pregnancy.

UK regulators recommend stopping the medication at least one month before trying to conceive, because tirzepatide has a half-life of around five days and can take roughly four weeks to clear from the body after the last dose.¹

If you’ve just found out you’re pregnant and you’ve been taking Mounjaro, it’s recommended to stop the medication and contact your prescriber, GP, or midwife.

Reassuringly, studies looking at women who took a GLP-1 medication early in pregnancy before they knew they were pregnant have not found higher rates of birth defects compared to women who didn’t take one.

UK guidance doesn’t recommend additional fetal monitoring on those grounds alone.^2,3

This guide covers what UK clinical guidance says about Mounjaro and pregnancy, what the current evidence shows, and how to plan stopping the medication if you’re trying to conceive.

What UK clinical guidance says

The Mounjaro Summary of Product Characteristics (the formal MHRA-approved prescribing document) section 4.6 states that tirzepatide shouldn’t be used during pregnancy and isn’t recommended in women of childbearing potential who aren’t using contraception.

The same section adds that if a patient wishes to become pregnant, tirzepatide should be stopped at least one month before a planned pregnancy due to the long half-life of the medication.¹

In June 2025, the MHRA reinforced this in a public safety update, advising that GLP-1 medicines (a class of weight management and diabetes medications that includes Mounjaro, Wegovy, and Ozempic) must not be taken during pregnancy, while trying to get pregnant, or during breastfeeding.⁴

The accompanying GOV.UK patient page, last updated in February 2026, sets out the washout periods clearly: tirzepatide needs at least one month, semaglutide-based medications need at least two months, and liraglutide can be stopped just before trying because it leaves the body much more quickly.⁵

The NHS Specialist Pharmacy Service guidance for healthcare professionals takes the same position, citing the lack of human safety data.³

The UK Teratology Information Service (UKTIS), which advises clinicians on medication use during pregnancy, adds that GLP-1 medication at any stage in pregnancy is not, on its own, a reason to consider ending the pregnancy or to add extra scans or tests beyond your standard antenatal care.²

What the evidence says about tirzepatide and pregnancy

The reason Mounjaro isn’t recommended in pregnancy comes down to two factors.

Animal studies have shown reproductive toxicity, and there isn’t enough data from pregnant humans to establish safety either way.¹

Animal studies

The Mounjaro SmPC reports that animal studies have shown signs of harm to the developing offspring.¹

A 2025 narrative review by Varughese and colleagues describes the broader animal-data picture for GLP-1 receptor agonists: lower fetal weight, delayed bone development, skeletal differences, and abnormalities in internal organs in animals exposed during gestation.⁶

Many of these effects occurred at doses that also caused maternal weight loss, which makes interpretation harder but doesn’t remove the regulatory concern.

Human pregnancy data

Pregnant women are routinely excluded from initial clinical trials of new medications.

Most human data on tirzepatide in pregnancy, therefore, comes from inadvertent exposures captured in regulatory or observational research.

There are three recent publications worth highlighting.

The first is a 2025 analysis by Parker and colleagues in Diabetes, Obesity and Metabolism, which reviewed regulatory clinical trial data across all licensed GLP-1 receptor agonists.

Across 32,598 women in the development programmes, 164 unplanned pregnancies were recorded.

In the tirzepatide development programme, the captured outcomes among six pregnancies included one healthy child, one spontaneous miscarriage, one ectopic pregnancy, and one elective termination.

Two pregnancies had no reported outcomes.⁷

The second is a 2024 prospective cohort study by Dao and colleagues in BMJ Open, drawing on six European teratology information services.

It compared 168 first-trimester GLP-1 exposures with 156 pregnancies in women with diabetes and 163 in women with a BMI above 27 and no GLP-1 exposure.

In the GLP-1 group, 2.6% of babies were born with a major birth defect.

That rate was no higher than in the comparison groups: women with diabetes taking other medications, and women with obesity not taking a GLP-1.

The differences between groups were small enough that they could easily have happened by chance.⁸

The third is a 2024 cohort study by Cesta and colleagues in JAMA Internal Medicine, which used Nordic, Israeli, and US registries to examine 938 pregnancies with periconceptional exposure to GLP-1 receptor agonists.

Compared with insulin, GLP-1 use during pregnancy didn’t increase the risk of major birth or heart defects.⁹

The conclusion across all three studies is the same. Existing evidence doesn’t suggest tirzepatide poses a risk of birth defects after early inadvertent exposure, but that’s a different statement from saying it’s safe to use during pregnancy.

Sample sizes remain limited, most exposures captured in the data were confined to early pregnancy, and tirzepatide is still not recommended for women who are pregnant.

Taking Mounjaro before you knew you were pregnant is currently regarded as low-risk by UKTIS. Continuing to take it after pregnancy is confirmed is different, and the SmPC says tirzepatide shouldn’t be used.^1,2

Stopping Mounjaro before trying to conceive

Tirzepatide has a half-life of approximately 5 days, meaning it takes about 4 weeks for the medication to clear from the body after the last dose.¹

The MHRA’s one-month washout period is built around this clearance window.

Practically, this means:

• Speak to your prescriber as early as possible if you’re planning a pregnancy
• Stop Mounjaro at least four weeks before you start trying to conceive
• Tirzepatide doesn’t need to be tapered. You can stop at the next scheduled dose.
• If you have type 2 diabetes, your prescriber will discuss alternative blood sugar management before, during, and after pregnancy. Metformin and insulin are the standard options in pregnancy.
• Most women planning a pregnancy are advised to take folic acid before conception. The standard NHS recommendation is 400 micrograms daily, with a higher 5 mg daily dose if you have diabetes, are taking certain medications, or have other risk factors. Your GP can confirm what’s right for you.

Weight regain after stopping

One thing to plan for is the likelihood of regaining some weight after stopping the medication.

The SURMOUNT-4 trial followed adults with obesity who had reached a stable dose of tirzepatide and then either continued the medication or switched to a placebo.

Those who switched to placebo regained an average of around 14% of their body weight over the following 88 weeks, while those who stayed on tirzepatide continued to lose weight.¹⁰

Higher pre-conception weight is associated with increased pregnancy risks, including gestational diabetes, gestational hypertension, pre-eclampsia, and macrosomia.¹¹

The implication isn’t that you should delay coming off the medication, but that you should plan support for weight maintenance during the four-week washout and the months of trying to conceive.

That might be a structured nutrition and habit-change programme, support from your GP, or referral to NHS specialist weight management services if you’re eligible.

Mounjaro and contraception

Mounjaro is currently the only GLP-1 receptor agonist licensed in the UK that has been shown to reduce the absorption of oral contraceptives.³

A study referenced in the Mounjaro SmPC measured what happened when women took a single 5 mg dose of tirzepatide alongside a combined oral contraceptive.

Tirzepatide reduced both the peak blood level and the overall amount of the contraceptive hormones (ethinyl estradiol and norgestimate) absorbed.¹

The Faculty of Sexual and Reproductive Healthcare (FSRH) recommends that women taking the combined or progesterone-only pill alongside Mounjaro should either:

• Switch to a non-oral method of contraception, or
• Add a barrier method (such as condoms) for four weeks after starting Mounjaro and for four weeks after each dose increase

This advice doesn’t apply to all forms of hormonal contraception. Methods that bypass the gut, including the contraceptive injection, implant, intrauterine device (IUD or coil), patch, and vaginal ring, aren’t affected by tirzepatide and don’t need additional precautions.³

If you’re using oral contraception and starting Mounjaro, raise the contraception question with your prescriber at the same appointment.

Your prescriber may suggest switching to a long-acting reversible method, which has the practical benefit of removing the four-week barrier-method window every time your dose increases.

What to do if you get pregnant while taking Mounjaro

If you discover you’re pregnant while taking Mounjaro:

• Stop the medication. Don’t take any more doses.
• Contact your prescriber, GP, or midwife as soon as possible. They can advise based on your specific circumstances (existing diabetes, dose history, other medications).
• Your healthcare team may submit a report to the MHRA Yellow Card Scheme, which helps regulators track real-world pregnancy outcomes after GLP-1 exposure.
• You don’t need to taper the dose. Tirzepatide can be stopped immediately.

Antenatal care continues as normal. UKTIS specifically advises that taking a GLP-1 medication before pregnancy is confirmed isn’t a reason to recommend extra scans or tests, or to consider ending the pregnancy on medical grounds.²

You can expect your standard 12-week dating scan and 20-week anomaly scan. Your antenatal team will discuss whether anything else is needed based on your wider clinical picture.

If you have type 2 diabetes, the priority shifts to managing your blood sugar safely without tirzepatide.

Insulin is well-established as a safe option in pregnancy and is what most prescribers will recommend.

Your diabetes specialist team will plan this with you.

Mounjaro and breastfeeding

The public-facing MHRA guidance and the Mounjaro Summary of Product Characteristics give different recommendations on breastfeeding.

The MHRA’s general public guidance on the GOV.UK GLP-1 patient page advises that GLP-1 medicines including Mounjaro shouldn’t be taken during breastfeeding due to a lack of human safety data.⁵

The Mounjaro SmPC states that tirzepatide may be considered for use during breastfeeding, based on a small study that measured how much passed into breast milk in 11 women given a single 5 mg dose.

The amount in breast milk was either undetectable or very low (less than 10 nanograms per millilitre) compared with blood levels.¹

The SmPC also notes that tirzepatide is an amino acid sequence (essentially a protein), so any small amount that does pass into breast milk is expected to be broken down in the baby’s gut rather than absorbed as active medication.¹

The general public guidance is conservative because it covers all GLP-1 medications, including those without breast milk data. The SmPC reflects what’s specifically known about tirzepatide.

In practice, this is a discussion to have with your prescriber and midwife, who can weigh the evidence, your specific clinical situation, and your feeding preferences with you.

Restarting Mounjaro after pregnancy

There’s no single rule about when to restart Mounjaro after pregnancy.

The decision sits with your prescriber and depends on whether you’re breastfeeding, your postpartum recovery, and your wider clinical picture.

A few practical points:

• If you’re breastfeeding, the decision should be made jointly with your prescriber and midwife, given that the SmPC and general guidance differ. Some women will choose to wait until weaning is complete; others will discuss restarting earlier with their clinical team.
• If you’re not breastfeeding, your prescriber may consider restarting Mounjaro once your postpartum recovery is established. There’s no fixed minimum interval, but allowing time for healing, sleep recovery, and re-establishing eating patterns is usually sensible.
• NHS specialist weight management services apply the same eligibility criteria as before pregnancy. Having been pregnant doesn’t change whether you qualify.
• If you’re considering restarting, raise it at your six-to-eight-week postnatal check or schedule a separate appointment with your GP

Fertility, PCOS, and IVF on Mounjaro

The Mounjaro SmPC states that the effect of tirzepatide on human fertility is unknown, and animal studies didn’t show direct harmful effects on fertility.¹

In humans, the practical picture is different. For women with overweight or obesity, weight loss often improves fertility indirectly.

Reducing body weight can lower insulin resistance and androgen levels, restore more regular menstrual cycles, and support more reliable ovulation.⁶

This is particularly relevant for women with polycystic ovary syndrome (PCOS), where insulin resistance and elevated androgens are central drivers of fertility problems.

A 2024 systematic review and meta-analysis by Goldberg and colleagues, which informed the 2023 international evidence-based guideline on PCOS, found that GLP-1 receptor agonists, including liraglutide and semaglutide, were better than placebo for weight loss in women with PCOS.¹²

Tirzepatide-specific research in PCOS is still limited because the medication is newer, but the underlying mechanism (weight loss improving insulin resistance) is the same.

Mounjaro isn’t licensed in the UK for fertility, PCOS, or pre-conception weight loss.

The MHRA-approved indications are type 2 diabetes and weight management in adults meeting specific BMI criteria.

If you have PCOS and are considering Mounjaro, your prescriber will assess whether you meet the standard eligibility criteria, with PCOS as additional clinical context rather than the indication itself.

If you’re starting an IVF cycle or other assisted conception treatment, Mounjaro should be stopped at least one month before the cycle begins, in line with the standard pre-conception advice.¹

Many fertility clinics will ask about GLP-1 use during the initial consultation, so flag it early.

Mounjaro vs Wegovy in pregnancy

If you’re comparing the two main GLP-1 weight loss medications and pregnancy is a consideration, the table below summarises the key differences.

For a full breakdown of how Wegovy is approached in pregnancy, see our companion guide on Wegovy in pregnancy.

When to speak to your GP

Contact your GP, prescriber, or midwife if:

• You’re planning to try for a baby and want to come off Mounjaro safely
• You think you might be pregnant while taking Mounjaro
• You’ve missed a period and aren’t sure if it’s due to weight loss or pregnancy
• You’re taking the contraceptive pill and starting or increasing Mounjaro
• You’re undergoing or planning IVF or other assisted conception
• You’re considering breastfeeding while on Mounjaro and want to discuss the trade-offs
• You’re managing your weight before pregnancy and want a plan that doesn’t rely on GLP-1 medication

Frequently asked questions

How long should I be off Mounjaro before trying to get pregnant?

The MHRA and the Mounjaro SmPC recommend stopping at least one month (four weeks) before trying to conceive.^1,5 This allows time for tirzepatide, which has a five-day half-life, to clear from your system.

Some prescribers may suggest waiting longer if you’re planning a precise conception window, but four weeks is the regulatory minimum.

I just found out I’m pregnant, and I’ve been taking Mounjaro. What should I do?

Stop taking Mounjaro and contact your prescriber, GP, or midwife as soon as you can.

UKTIS guidance is that taking a GLP-1 medication before pregnancy is confirmed isn’t a reason for additional scans or tests, or to consider ending the pregnancy on medical grounds.²

Early antenatal contact lets your team plan care that suits your situation.

Will Mounjaro have harmed my baby if I had been taking it before I knew I was pregnant?

The available human evidence to date doesn’t suggest that taking a GLP-1 medication, including tirzepatide, before pregnancy increases the risk of birth defects.^7,8,9

The 2024 Dao study of 168 first-trimester GLP-1 exposures and the 2024 Cesta study of 938 periconceptional GLP-1 exposures both found no significant increase in major birth defects.

Can I breastfeed while taking Mounjaro?

The Mounjaro SmPC says tirzepatide could be considered for use during breastfeeding, based on a small study showing very low or undetectable levels in breast milk.¹

The MHRA’s general public guidance is more conservative and advises against. This is a discussion to have with your prescriber and midwife, who can weigh the evidence and your specific situation rather than rely on a single guideline.

Does Mounjaro affect my contraceptive pill?

Yes. Mounjaro is the only GLP-1 receptor agonist licensed in the UK that has been shown to reduce the absorption of oral contraceptives.³

If you take the pill, the FSRH advises adding a barrier method (such as condoms) for four weeks after starting Mounjaro and for four weeks after each dose increase, or switching to a non-oral method like the implant, IUD, patch, or ring.³

Can Mounjaro improve fertility if I have PCOS?

Weight loss in women with PCOS can improve insulin sensitivity, lower androgens, and restore more regular ovulation.¹²

Mounjaro can support that weight loss, which may indirectly improve fertility. It’s not, however, licensed as a fertility treatment, and you’d need to stop the medication at least one month before trying to conceive.

Should I stop Mounjaro for IVF?

Yes. Mounjaro should be stopped at least one month before an IVF cycle begins.¹

Many fertility clinics will ask about GLP-1 use during initial consultations. Flag it early so your fertility team can plan timing alongside your prescriber.

Will my prescriber report my pregnancy to the MHRA?

Your healthcare team may submit a report to the MHRA Yellow Card Scheme, which collects data on pregnancy outcomes after exposure to GLP-1 medicines.

This is anonymous and contributes to the long-term evidence base on these medications in pregnancy. You can also report to the Yellow Card Scheme yourself if you’d prefer to.

Can my partner take Mounjaro while we’re trying for a baby?

There’s no current evidence that paternal exposure to tirzepatide affects pregnancy outcomes. Animal studies in male rats didn’t indicate harmful effects on fertility.¹

Most clinical guidance focuses on maternal exposure. If you have concerns about a partner’s use, raising it with the prescriber is the right step.

How soon after giving birth can I restart Mounjaro?

There’s no fixed minimum interval. If you’re breastfeeding, the decision should be made jointly with your prescriber and midwife, given that the SmPC and general guidance differ.

If you’re not breastfeeding, your prescriber may consider restarting once your postpartum recovery is established. Discussing this at your six-to-eight-week postnatal check is a sensible starting point.

Can I get an NHS prescription for Mounjaro after pregnancy?

Mounjaro is available through NHS specialist weight management services for adults meeting specific eligibility criteria.¹³

Eligibility doesn’t change because of pregnancy. It’s based on the same BMI and clinical criteria as for anyone else. Your GP can refer you to an appropriate service.

Take home message

Mounjaro shouldn’t be used during pregnancy. The UK clinical guidance is clear: stop the medication at least one month before trying to conceive, use reliable contraception while taking it, and contact your prescriber if you become pregnant unexpectedly.

The available evidence on inadvertent first-trimester exposure is reassuring across three independent studies, and UKTIS doesn’t consider it a reason for additional monitoring or termination.

On breastfeeding, the SmPC and the general public guidance differ, and that question is best discussed with your prescriber and midwife.

If you’re planning a family or thinking about coming off Mounjaro, that conversation is best had early with your prescriber so you have time to plan weight maintenance, blood sugar control where relevant, and contraception alongside the transition.

At Second Nature, we support members at every stage of taking GLP-1 medications, including coming off the medication and maintaining weight afterwards.

Our programme combines evidence-based nutrition built around the balanced plate model (half vegetables, quarter protein, quarter complex carbohydrates, plus a serving of fat) with habit-change coaching and ongoing clinical oversight.

Our published outcomes from a 2025 JMIR Formative Research study show an average 19.1% body weight loss at 12 months among active subscribers, with 77.7% achieving at least 10% weight loss.¹⁴

References

1. Electronic Medicines Compendium. (2026). Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen – Summary of Product Characteristics.
2. UK Teratology Information Service. (2025). Use of GLP-1 receptor agonists in pregnancy.
3. NHS Specialist Pharmacy Service. (2025). Considerations and interactions with GLP-1 receptor agonists.
4. Medicines and Healthcare products Regulatory Agency. (2025). Women on ‘skinny jabs’ must use effective contraception, MHRA urges in latest guidance. GOV.UK.
5. Department of Health and Social Care. (2026). GLP-1 medicines for weight loss and diabetes: what you need to know. GOV.UK.
6. Varughese, M.S., O’Mahony, F., and Varadhan, L. (2025). GLP-1 receptor agonist therapy and pregnancy: Evolving and emerging evidence. Clinical Medicine, 25(2), 100298.
7. Parker, C.H., Slattery, C., Brennan, D.J., and le Roux, C.W. (2025). Glucagon-like peptide 1 (GLP-1) receptor agonists’ use during pregnancy: Safety data from regulatory clinical trials. Diabetes, Obesity and Metabolism, 27(8), 4102-4108.
8. Dao, K., Shechtman, S., Weber-Schoendorfer, C., et al. (2024). Use of GLP1 receptor agonists in early pregnancy and reproductive safety: a multicentre, observational, prospective cohort study based on the databases of six Teratology Information Services. BMJ Open, 14(4), e083550.
9. Cesta, C.E., Rotem, R., Bateman, B.T., et al. (2024). Safety of GLP-1 Receptor Agonists and Other Second-Line Antidiabetics in Early Pregnancy. JAMA Internal Medicine, 184(2), 144-152.
10. Aronne, L.J., Sattar, N., Horn, D.B., et al. (2024). Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. JAMA, 331(1), 38-48.
11. National Institute for Health and Care Excellence. (2010). Weight management before, during and after pregnancy. Public Health Guideline PH27.
12. Goldberg, A., Graca, S., Liu, J., et al. (2024). Anti-obesity pharmacological agents for polycystic ovary syndrome: A systematic review and meta-analysis to inform the 2023 international evidence-based guideline. Obesity Reviews, 25(5), e13704.
13. National Institute for Health and Care Excellence. (2024). Tirzepatide for managing overweight and obesity. Technology Appraisal TA1026.
14. Richards, R., Whitman, M., Wren, G., and Campion, P. (2025). A Remotely Delivered GLP-1RA-Supported Specialist Weight Management Program in Adults Living With Obesity: Retrospective Service Evaluation. JMIR Formative Research, 9, e72577.