Chances of Getting Pregnant on Mounjaro (October 2026)

01 · The short answer

What are your chances of getting pregnant on Mounjaro?

Your chances are the same as for anyone who is ovulating and not using effective contraception, and they may rise if weight loss restores ovulation.

The first is contraception. Mounjaro slows how quickly the stomach empties, which can reduce how well oral contraceptive pills are absorbed.¹ If the pill is absorbed less well, it may protect you less. That is the main route to an unplanned pregnancy on treatment.

The second is ovulation. Mounjaro is not licensed specifically for PCOS, but weight loss is a first-line recommendation for it and can improve insulin resistance, cycles and symptoms. Improving weight can restore ovulation.¹ Someone who has had irregular or absent cycles may therefore become fertile again without expecting it.

02 · Your next step

What should you do if you are not trying to conceive?

Use a method that does not depend on stomach absorption, or add a barrier method. The SmPC advises switching to a non-oral method, or adding a barrier method such as condoms, for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ This applies to the pill only. Implants, coils and injections are unaffected.¹ The MHRA also publishes guidance on contraception with these medicines.⁷

Because the dose rises step by step, there will be several of these 4-week windows in your first months. Put the dates in your calendar when you start and again whenever your prescriber increases the dose.

03 · If you want a baby

What if you want to get pregnant?

Plan the timing with your prescriber, because Mounjaro should be stopped at least one month before trying to conceive.¹ Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4–5 weeks to clear the system.¹ There is no way to speed this up, and nothing needs doing while it clears. Our page on taking a GLP-1 medicine before pregnancy covers the planning side.

04 · Getting treatment

How to start Mounjaro with a pregnancy plan in mind

Tell the prescriber about any plan to conceive in the next year, and about the contraception you use. Our consultation is free, and every order is reviewed by a GPhC-registered prescriber.

• Step 1: complete the free online consultation, a short health questionnaire with no charge and no obligation.
• Step 2: a GPhC-registered prescriber reviews it.

You can start your free consultation now.

05 · Contraception rules

Which contraception works with Mounjaro?

Only the contraceptive pill is affected, because it relies on absorption through the stomach.

If you are unsure which category your method falls into, ask your prescriber or pharmacist. Changes to contraception are best made before you start treatment rather than after. The MHRA also runs the Yellow Card scheme, where you can report any suspected problem with a medicine.¹⁹

06 · PCOS and ovulation

PCOS, weight loss and ovulation

If you have PCOS, losing weight can bring ovulation back, which is one reason pregnancy can happen when you did not expect it. Mounjaro is not licensed specifically for PCOS. Many women with PCOS do meet the licensed weight-management criteria, and weight loss itself is a first-line recommendation that can improve insulin resistance, cycles and symptoms.¹

Eligibility is assessed on the standard BMI criteria: a BMI of 30 or above, or 27 to 30 with at least one weight-related condition.¹ Mention PCOS and any fertility plans in your consultation.¹

Do not treat irregular cycles as protection. Absent or unpredictable periods before treatment do not mean you cannot conceive after weight change. Our pages on women getting pregnant on treatment and whether the injection affects fertility expand on this.

07 · Stopping before conception

Stopping Mounjaro before you try to conceive

Stop Mounjaro at least one month before you start trying.¹ That matches how the medicine leaves your body: with a half-life of about five days, it takes roughly 4–5 weeks to clear after your final dose.¹

In practice, that means continuing reliable contraception until you stop the injection, then waiting at least one month before you try. Speak to your prescriber about the timing so that your weight management plan continues sensibly.

Mounjaro works alongside a reduced-calorie diet and increased physical activity, not instead of them.² Keeping those habits going during the gap is the part within your control.

08 · If you conceive on treatment

What happens if you get pregnant while on Mounjaro?

Stop the medicine and tell your prescriber promptly.¹ Mounjaro must not be used during pregnancy.¹ Do not wait for your next scheduled review or finish the pen first.

Your prescriber and your GP or midwife are the right people to talk through your circumstances. If you want to report a suspected effect of a medicine taken in early pregnancy, the MHRA Yellow Card scheme accepts reports.¹⁹

If you think you may be pregnant, take a test rather than waiting for the next dose day. You can read more about this scenario on our page about people who become pregnant on Mounjaro.

09 · Ozempic babies explained

What are "Ozempic babies"?

"Ozempic babies" is a media phrase for pregnancies that happen unexpectedly while someone is taking a weight-loss injection. It is not a medical term. Ozempic is semaglutide licensed for type 2 diabetes — it is not a UK weight-loss medicine, and prescribing it privately for weight loss is off-label.

There are two explanations: reduced pill absorption because stomach emptying slows,¹ and weight loss that can restore ovulation.¹ Both are manageable with planning. The practical lesson is simple: do not assume you are infertile, and do not assume the pill is working as before.

10 · Periods and cycles

Does Mounjaro affect periods?

Weight loss can improve cycles in women with PCOS and can restore ovulation.¹

So a change in your cycle during treatment can be linked to weight change, but a missed period should never be assumed to be "just the medicine". If your period is late, take a pregnancy test. Discuss any new or persistent symptoms with your prescriber, and you can report suspected side effects through the Yellow Card scheme.¹⁹

11 · Breastfeeding and later

Breastfeeding, and slower stomach emptying

Current prescribing information indicates minimal transfer of tirzepatide into breast milk, but you should discuss breastfeeding with your prescriber so the decision reflects your circumstances.¹

Gastroparesis is sometimes raised in this context, because slower stomach emptying is part of how the medicine works. Our page on the chances of gastroparesis from tirzepatide addresses that separately.

12 · Our safety summary

Pregnancy safety summary

Mounjaro (tirzepatide) is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary.

Before you start, check three things: your contraception does not rely on the pill alone, you have told the prescriber about any plan to conceive, and you know to stop the medicine and call if you might be pregnant.¹

After you start, keep a note of each dose increase and use extra protection for the following 4 weeks if you take the pill.¹

You can also see our page for quick answers on getting pregnant on Mounjaro.