Plan before you try to conceive
Talk to your prescriber about pregnancy plans before you stop contraception. Tirzepatide stays in your body after the last injection. For this reason the label sets a gap of at least one month before a planned pregnancy. Stopping on the day of a positive test does not give you the same preparation.
If you have diabetes, you need a replacement plan for managing your glucose. Good care before pregnancy covers more than switching one medicine. Arrange a review of your whole treatment, the monitoring you need and pregnancy preparation with your diabetes or maternity team.
If you become pregnant during treatment
Contact your prescriber promptly and take no more tirzepatide while you wait for pregnancy advice. Give your dose, the date of your last injection and how far along you think you are. A clinician can assess the exposure and arrange the right pregnancy and diabetes care.
Accidental exposure does not prove harm has occurred. Human evidence is limited, and good counselling avoids both false reassurance and needless alarm. Do not make major pregnancy decisions on the strength of a social media post or a headline about an animal study.
Agree a clear contraception plan
UK advice for tirzepatide is a non-oral contraceptive, or an added barrier method, for four weeks after starting and for four weeks after every dose increase. Vomiting or diarrhoea cause separate problems with pill absorption. A pharmacist or sexual health service can apply the rules to your method.
If your protection may have failed, get prompt advice about emergency contraception. Do not wait to see whether your period arrives. The best option depends on your circumstances and timing. Tirzepatide is neither a contraceptive nor an approved fertility treatment.
Why breastfeeding advice looks inconsistent
The current UK SmPC, revised in August 2026 and published on emc in September, includes a small study of transfer into breast milk. The SmPC says tirzepatide use can be considered during breastfeeding. Older MHRA public material advised avoiding GLP-1 medicines while breastfeeding. The two statements differ, and older summaries may miss the updated evidence for this product.
The study found milk levels were extremely low or undetectable after a single 5 mg dose in 11 women. The study did not cover repeated higher doses, outcomes for babies or how eating less affects the nutrition in breast milk. The updated wording supports a personal discussion with your clinician. Do not use tirzepatide while breastfeeding without supervision.
Decide around you and your baby
A breastfeeding review should look at why you need treatment, the alternatives, your baby's age and health, your feeding pattern and how well you are eating. If you have diabetes, your team should also consider the safest way to keep your glucose under control. Ask your clinician to check the latest UK product information, because advice in this area keeps changing.
Keep questions about pregnancy, contraception and breastfeeding part of your ongoing prescription. Your provider should explain what changes when your circumstances change and how to contact them quickly. Advice for one GLP-1 product does not automatically apply to another.
Sources
Your own medicine leaflet and prescriber come first. A source from another country does not mean the same rule applies in the UK.
- Mounjaro UK Summary of Product Characteristics, updated September 2026 medicines.org.uk
- Mounjaro UK patient information leaflet medicines.org.uk
- MHRA: GLP-1 medicines, what you need to know gov.uk
- NICE: prescribing, reviewing and stopping tirzepatide nice.org.uk
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