EN
Home/United Kingdom/Blog/Mounjaro, Wegovy, pregnancy and the pill: what does the MHRA say?
UKUnited Kingdom Safety

Mounjaro, Wegovy, pregnancy and the pill: what does the MHRA say?

Contraception, the wash-out periods before trying for a baby, the Mounjaro pill warning, and breastfeeding: UK labels and MHRA guidance.

GLP Guidebook teamPublished 12 Oct 20269 min read19 sourcesWritten from published sources

Written for the UK. Reading from India? India version

The short answer

The MHRA says not to take GLP-1 medicines in pregnancy or while trying to conceive. Stop semaglutide (Wegovy, Ozempic) at least 2 months before, and tirzepatide (Mounjaro) at least 1 month before. On Mounjaro, the pill may work less well: use a non-pill method or add condoms for 4 weeks after starting and after each dose increase.

Key takeaways

  • The MHRA says GLP‑1 medicines should not be taken during pregnancy or just before trying to conceive, because there is not enough safety data.1
  • The MHRA wash-out periods before a planned pregnancy are at least 2 months for semaglutide, at least 1 month for tirzepatide, and 0 months for liraglutide.1
  • On Mounjaro, the UK label advises switching from the pill or adding a barrier method for 4 weeks after starting and for 4 weeks after each dose increase.2
  • In the UK Mounjaro label, one 5 mg dose cut the peak level of the pill’s oestrogen by 59% and the total by 20%.2
  • The largest study found major birth defects in 8.3% of 938 babies exposed to a GLP‑1, against 7.8% after insulin, in mothers with type 2 diabetes.3
On this page
  1. What do the UK labels and the MHRA say about pregnancy?
  2. How long before trying for a baby do you stop?
  3. Does Mounjaro make the contraceptive pill less reliable?
  4. What if you get pregnant while taking one?
  5. What have studies of exposed pregnancies found so far?
  6. Can these medicines make pregnancy more likely?
  7. Can you breastfeed while taking a GLP-1 medicine?
  8. Questions people ask
  9. How we researched this

What do the UK labels and the MHRA say about pregnancy?

Don't take them in pregnancy or while trying to conceive. The MHRA says there is not enough safety data to know whether they could harm a baby.1

Before you go further
  • GLP‑1 medicines are prescription-only in the UK. On the NHS or privately, a healthcare professional has to assess you before a prescription is issued.1
  • The label facts here come from the UK product information (the SmPC, the official label each maker publishes on the electronic Medicines Compendium). Where we use a US or EU label instead, we say so.
  • Every risk of these medicines is in Guide 5: Side effects and risks.
  • This post describes labels, guidance and trials. It is not a plan for your treatment, and no dose or brand guarantees any result.

The MHRA says anyone who could become pregnant should use contraception, or avoid sex that could lead to pregnancy, while taking a GLP‑1 medicine.1 That continues for a "wash-out" period after stopping.1 In some animal studies, these medicines harmed the unborn young.1

  • Wegovy and Ozempic (semaglutide): the UK labels say semaglutide "should not be used during pregnancy".4,5
  • Mounjaro (tirzepatide): the UK label says it "should not be used during pregnancy". It is not recommended for women who could get pregnant and are not using contraception.2
  • Saxenda (liraglutide): the UK label says liraglutide "should not be used during pregnancy".6

In June 2025 the MHRA reminded women on these medicines to use effective contraception. It said the advice was already in the patient leaflets.7

How long before trying for a baby do you stop?

At least 2 months for semaglutide and at least 1 month for tirzepatide, says the MHRA. Liraglutide leaves the body quickly, so it is stopped just before trying.1

MedicineStop before a planned pregnancyThe pillBreastfeeding
SemaglutideWegovy, Ozempic, RybelsusAt least 2 months1,4Not expected to make it less effective4Should not be used4,8
TirzepatideMounjaroAt least 1 month1,2Switch to a non-pill method, or add a barrier method, for 4 weeks after starting and after each dose increase1,2UK label: “could be considered”. MHRA guidance: should not be taken1,2
LiraglutideSaxenda and other brands0 months: stop just before trying1Effect “anticipated to be unaffected”6Should not be used6

UK labels (SmPCs) and MHRA guidance updated 5 February 2026, checked 12 Oct 2026.

Why the gap differs. Semaglutide's half-life (time for half of it to leave the blood) is about a week. The UK Wegovy label says it stays in the blood about 7 weeks after a 2.4 mg dose.4 Tirzepatide's half-life is about 5 days, and liraglutide's about 13 hours.2,6

For women with type 2 diabetes, stopping one medicine means another must control blood sugar, which is planned with the diabetes team. What happens to weight after stopping is in what happens when you stop.

Does Mounjaro make the contraceptive pill less reliable?

It may, in people with overweight or obesity. The UK label and the MHRA advise a non-pill method, or condoms as well, for 4 weeks after starting and after each dose increase.1,2

Tirzepatide slows the stomach, so a pill is absorbed later and less sharply. In a study on the UK label, one 5 mg dose cut the peak level of the pill's oestrogen by 59%, and the total by 20%.2 The UK label says there is limited information in women with obesity or overweight, so reduced effect "cannot be excluded".2

The MHRA names the coil and the implant as methods not as affected by GLP‑1s.1 The UK sexual health faculty's interim advice agrees, and lists the vaginal ring and the patch as other non-pill options.9

How long that window can run. Your prescriber sets the dose; this example only follows the UK label. It starts at 2.5 mg a week, then allows a 2.5 mg step after at least 4 weeks on each dose.2 Someone stepped up every 4 weeks to 10 mg makes 3 increases, so the 4-week windows run back to back for about 16 weeks (our arithmetic).

Semaglutide and liraglutide carry no pill warning. The UK Wegovy label says semaglutide is not expected to reduce the pill's effect.4 The Saxenda label says the pill's effect is "anticipated to be unaffected".6

Sickness is a separate route. Vomiting and diarrhoea are common on these medicines.1 The NHS says vomiting within 3 hours of a combined pill means taking another straight away.10 For diarrhoea lasting more than 24 hours, it says to use condoms too until 7 days after it stops.10

Free toolPlan the questions for your appointment

Pick the topics that matter to you, including pregnancy plans and contraception, and print a short list. No sign-up.

Open the question list

What if you get pregnant while taking one?

Speak to a healthcare professional straight away, the MHRA says, and stop the medicine as soon as possible.1,7

The UK Wegovy label asks that any pregnancy on Wegovy be reported to a Novo Nordisk pregnancy registry, a study that follows exposed pregnancies.4 You can also report a suspected side effect to the MHRA's Yellow Card scheme.11

What have studies of exposed pregnancies found so far?

Two studies, of 938 babies and 168 pregnancies, found no large rise in birth defects. A Danish study found more preterm births, only in women taking them for diabetes.3,12,13

The largest study (2024) used health records from Nordic countries, the US and Israel, in women with type 2 diabetes. Of 938 babies exposed early in pregnancy, 8.3% had a major birth defect, against 7.8% after insulin.3 The adjusted relative risk was 0.95 (range 0.72 to 1.26). The authors said this did not show a large added risk, but needs confirming.3

A European study (2024) followed 168 pregnancies exposed in the first trimester. Major birth defects were 2.6%, against 2.3% in women with diabetes and 3.9% in women with overweight or obesity.12 It called for larger studies.12

A Danish study (2026) looked at 529 pregnancies exposed around conception. After matching, only preterm birth stayed higher, and only in women taking them for diabetes. The design "cannot establish causality".13 A 2025 review said registries of exposed pregnancies are "a high priority".14

Can these medicines make pregnancy more likely?

Surprise pregnancies on these medicines have been reported. Two Australian researchers think weight loss restoring ovulation is the likeliest reason.15

They wrote that weight loss and better metabolic health are "the most likely reasons", and that losing weight can make periods more regular.15 The UK labels say the effect of semaglutide and tirzepatide on human fertility is unknown.2,4 For Mounjaro there is also the pill effect above.2

Can you breastfeed while taking a GLP-1 medicine?

The MHRA says no for all of them. The UK Mounjaro label is less strict, saying tirzepatide "could be considered".1,2

The MHRA says GLP‑1 medicines "should not be taken by people who are breastfeeding", because there is not enough safety data.1 The UK Wegovy and Saxenda labels say they should not be used while breastfeeding.4,6 For Wegovy tablets, an added ingredient was found in breast milk.8

For tirzepatide, the UK label reports a study of 11 women given one 5 mg dose. Levels in milk were undetectable to very low.2 It says it is not known whether eating less on the medicine changes the milk.2 Where the label and the MHRA differ, that is a decision for you and your prescriber.

RisksThe risks, in brief
  • Stomach effects are very common (more than 1 in 10) on the UK Wegovy and Mounjaro labels, and vomiting or diarrhoea can affect the pill.2,4,10
  • Pancreatitis is uncommon (1 in 100 to 1 in 1,000); the sign is severe stomach pain that won’t go away and may spread to the back.2,16
  • Gallstones are common (1 in 10 to 1 in 100) on the UK Wegovy label.4
  • Dehydration from vomiting or diarrhoea can harm the kidneys.2
  • Not in pregnancy or while breastfeeding, the MHRA says.1
Full detail in Guide 5: Side effects and risks →
Get help now: call 999 for a life-threatening emergency.17 Call for severe stomach pain that won’t go away, especially if it spreads to your back.16 For urgent advice that is not an emergency, use NHS 111 in England, Scotland and Wales, online or by phone.18 Northern Ireland has no 111 service: call your GP practice or the GP out-of-hours service.19

Questions people ask

Does Mounjaro stop the pill working?

It may make it less reliable in people with overweight or obesity. The UK label and the MHRA advise a non-pill method, or condoms as well, for 4 weeks after starting and after each dose increase.1,2

How long after stopping Mounjaro can I try to get pregnant?

The MHRA and the UK label say stop at least 1 month before a planned pregnancy.1,2

How long after stopping Wegovy can I try to get pregnant?

At least 2 months, say the MHRA and the UK Wegovy label.1,4

Does Wegovy or Ozempic affect the pill?

The UK Wegovy label says semaglutide is not expected to make the pill less effective.4 Vomiting or long diarrhoea can, and the NHS has rules for that.10

Can I take Mounjaro while breastfeeding?

The MHRA says GLP‑1 medicines should not be taken while breastfeeding. The UK Mounjaro label says tirzepatide “could be considered”, so the two differ.1,2

What happens if I get pregnant on Mounjaro or Wegovy?

The MHRA says speak to a healthcare professional straight away and stop the medicine as soon as possible.1,7

Shorter answers: Does Mounjaro stop the pill working?

How we researched this

On 12 Oct 2026 we read the pregnancy, contraception and breastfeeding sections of 5 UK labels: Wegovy, Wegovy tablets, Ozempic, Mounjaro and Saxenda. We also read the MHRA’s guidance and June 2025 press release, the FSRH’s interim contraception advice and the NHS combined-pill page.

Study figures come from the papers’ abstracts, as checked for our India post. We left out a UK count of pregnancy reports that we found only second-hand. Where the UK Mounjaro label and the MHRA disagree on breastfeeding, we report both.

Before you move on

  • The MHRA says GLP‑1 medicines should not be taken in pregnancy or while trying to conceive.
  • MHRA wash-out periods: at least 2 months for semaglutide and 1 month for tirzepatide; liraglutide just before trying.
  • On Mounjaro, the UK label advises a non-pill method, or condoms as well, for 4 weeks after starting and after each dose increase.
  • Vomiting or long diarrhoea can affect any pill.
Side effects and risksI'm considering it for my weightDoctor questions tool

More from the UK blog

UKUnited KingdomMounjaro side effects, and reporting them UKUnited KingdomWegovy vs Mounjaro in the UK UKUnited KingdomWhat happens when you stop Mounjaro or Wegovy?
About GLP Guidebook

The monthly UK update

An independent guide to GLP‑1 medicines. We don't sell medicines, take drug-company money or earn clinic commissions. Once a month: NHS access changes, approvals, safety notices and recalls. How we write

Was this post easy to understand?

Sources

  1. MHRA (Medicines and Healthcare products Regulatory Agency). GLP‑1 medicines for weight loss and diabetes: what you need to know. First published 5 June 2025, updated 5 February 2026. gov.uk
  2. Eli Lilly. Mounjaro KwikPen (tirzepatide): UK summary of product characteristics (SmPC, the UK label), date of revision 29 August 2026. Sections 4.2, 4.4, 4.5, 4.6, 4.8, 5.2, 6.4. emc
  3. Cesta CE et al. Safety of GLP‑1 receptor agonists and other second-line antidiabetics in early pregnancy. JAMA Intern Med 2024;184(2):144–52. DOI · PMID 38079178
  4. Novo Nordisk. Wegovy FlexTouch (semaglutide) pens: UK summary of product characteristics (SmPC), date of revision 09/2026. Sections 4.1, 4.2, 4.4, 4.5, 4.6, 4.8, 5.1, 5.2, 6.3, 6.4. emc
  5. Novo Nordisk. Ozempic (semaglutide) pens: UK SmPC, date of revision 07/2026. Sections 4.1, 4.2, 4.4, 4.6, 4.8, 5.1, 5.2. emc
  6. Novo Nordisk. Saxenda (liraglutide) 6 mg/ml pen: UK SmPC, date of revision 11/2025. Sections 4.1, 4.2, 4.4, 4.6, 4.8, 5.1, 5.2, 6.3, 6.4. emc
  7. MHRA. Women on “skinny jabs” must use effective contraception, MHRA urges in latest guidance. Press release, 5 June 2025. gov.uk
  8. Novo Nordisk. Wegovy tablets (oral semaglutide): UK SmPC, first authorised 11 June 2026, date of revision 06/2026. Sections 4.2, 4.6. emc
  9. Faculty of Sexual and Reproductive Healthcare (FSRH, now the College of Sexual and Reproductive Healthcare, CoSRH) Clinical Effectiveness Unit. Members’ evidence response: oral contraceptive use with the GLP‑1 agonists tirzepatide and semaglutide. Interim advice while an expert group is convened; PDF created December 2024. cosrh.org (PDF)
  10. NHS. What to do if you’re sick or have diarrhoea when taking the combined pill. Page last reviewed 15 February 2024. nhs.uk
  11. MHRA. Yellow Card: making medicines and medical devices safer (reporting site; guest reports and the Yellow Card app). Opened 12 October 2026. yellowcard.mhra.gov.uk
  12. Dao K et al. 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 2024;14:e083550. DOI · PMID 38663923
  13. Hviid KVR et al. Periconceptional GLP‑1 receptor agonist exposure and obstetric outcomes: a Danish nationwide cohort study. Hum Reprod Open 2026. DOI · PMID 41852577
  14. Parker CH et al. GLP‑1 receptor agonists’ use during pregnancy: safety data from regulatory clinical trials. Diabetes Obes Metab 2025. DOI · PMID 40329607
  15. Hammarberg K, Norman R. What are “Ozempic babies”? Can the drug really increase your chance of pregnancy? The Conversation, 17 April 2024. theconversation.com
  16. MHRA. Drug Safety Update: GLP‑1 receptor agonists and dual GLP‑1/GIP receptor agonists: strengthened warnings on acute pancreatitis, including necrotising and fatal cases. Volume 19, issue 6, 29 January 2026. gov.uk
  17. NHS. When to call 999. Page last reviewed 3 February 2023. nhs.uk
  18. NHS. When to use NHS 111 online or call 111. Opened 12 October 2026. nhs.uk
  19. nidirect (Northern Ireland government). GP out of hours service. Opened 12 October 2026. nidirect.gov.uk

Last checked 12 Oct 2026 · Next review due 12 Oct 2027 · Report an error

How this post was made. Written by the GLP Guidebook team from the sources above. It's general information, not medical advice. Talk to a qualified doctor, nurse or pharmacist before starting, stopping or changing any medicine, or before planning a pregnancy on one. How we write