- No use in pregnancy: GLP-1 jabs should not be taken during pregnancy, when trying to get pregnant, or while breastfeeding.
- The pill can be less reliable: Mounjaro (tirzepatide) may reduce how well oral contraception works, particularly if you are overweight.
- The four-week rule: if you use the pill, add a barrier method (or switch to a non-oral method) for four weeks after starting Mounjaro and for four weeks after each dose increase.
- Before conceiving: stop semaglutide (Wegovy, Ozempic, Rybelsus) at least two months before trying; stop tirzepatide (Mounjaro) at least one month before.
- If you become pregnant on a jab: stop the medicine and speak to your healthcare professional as soon as possible.
- Report side effects: use the MHRA Yellow Card scheme.
What the MHRA has warned
In June 2025 the MHRA issued advice reminding women and people who can become pregnant to use effective contraception while taking GLP-1 medicines for weight loss or type 2 diabetes, and it updated its patient guidance again in February 2026. The named medicines include semaglutide (Wegovy, Ozempic, Rybelsus), tirzepatide (Mounjaro) and liraglutide (Saxenda, Victoza). The advice has two parts: these medicines must not be used around pregnancy at all, and — for Mounjaro specifically — the contraceptive pill may not work as reliably as usual.
The concern is that too many pregnancies were happening in people taking these medicines without knowing the risks. GLP-1 jabs have not been tested for safety in pregnancy, so the safest approach is to avoid them entirely if there is any chance of becoming pregnant. If you are taking one of these medicines and think you might be pregnant, do not stop suddenly without advice — contact your prescriber or pharmacist promptly and they will guide you.
Why the pill can be less reliable on Mounjaro
The MHRA highlights that Mounjaro (tirzepatide) may reduce the effectiveness of oral contraceptives in people who are overweight. Because of this, if you take the pill and are prescribed Mounjaro, the guidance is to not rely on the pill alone. The MHRA advises you either:
- Add a barrier method (such as condoms) for four weeks after starting Mounjaro, and for four weeks after any increase in your dose; or
- Switch to a non-oral method that is not affected in the same way — such as the coil (IUD/IUS) or the contraceptive implant.
Planning a pregnancy: how long to stop before trying
Because these medicines stay in the body for a while, the MHRA advises stopping before you start trying to conceive, not at the moment you decide to. The recommended gap differs by medicine:
| Medicine | Brands | Stop before trying to conceive |
|---|---|---|
| Semaglutide | Wegovy, Ozempic, Rybelsus | At least 2 months before |
| Tirzepatide | Mounjaro | At least 1 month before |
| Liraglutide | Saxenda, Victoza | Stop before trying (no set washout period stated) |
These are the MHRA's minimum gaps. Your GP or specialist may advise a different plan depending on your situation, so always agree a timeline with them before stopping a diabetes or weight-management medicine — particularly if you have type 2 diabetes, where your blood sugar will still need managing.
Breastfeeding
The MHRA advises that GLP-1 medicines should not be taken while breastfeeding, because it is not known whether the medicine passes into breast milk or how it might affect a baby. If you are breastfeeding and considering weight-loss or diabetes treatment, discuss the options with your GP or pharmacist first.
What to do if you become pregnant while taking a jab
- Speak to your healthcare professional as soon as possible — your GP, prescriber, pharmacist or midwife.
- Stop the medicine on their advice; do not simply keep taking it.
- Do not panic — being on a GLP-1 medicine early in an unplanned pregnancy is not a reason to assume harm, but it does need a prompt conversation with a clinician who knows your history.
- If you are unsure how urgently to act, NHS 111 can help you decide.
How to report a side effect (Yellow Card)
If you think you have had a side effect from a GLP-1 medicine — including a suspected contraception failure or a problem in pregnancy — you can report it to the MHRA through the Yellow Card scheme. Reporting is open to patients and carers as well as health professionals, and you do not need to be certain the medicine caused the problem — a suspicion is enough. These reports help the MHRA spot new safety signals. Reporting does not replace getting medical help: if you are unwell, still speak to your pharmacist, GP or NHS 111, and call 999 in an emergency.
Where to get help
- Your pharmacist — for advice on contraception options, how your medicines interact, and what the four-week rule means for you.
- Your GP, sexual-health clinic or weight-management/diabetes team — for choosing a non-oral method, planning a pregnancy, and agreeing when to stop a medicine.
- NHS 111 — if you are worried, think you may be pregnant, and are unsure how urgently you need to be seen.
- 999 or A&E — for any medical emergency.
Related reading
Mounjaro (tirzepatide) side effects
The MHRA-labelled side effects, the pancreatitis warning, and contraception advice.
Mounjaro UK: availability, price & NHS rollout
Supply status, the 2025 price rises, and how NHS access is being phased in.
Wegovy & Ozempic (semaglutide)
How the other main GLP-1 medicines compare on availability and access.
Does Mounjaro cause muscle loss?
What the trials show about lean mass, and how to protect muscle.
Orforglipron: the oral GLP-1
Where the first daily GLP-1 pill stands for UK availability.
Track weight-loss jab supply and safety updates
MediWatch checks official DHSC and NHS data daily and alerts you if your medication is affected.
Search shortages free →Official sources: MHRA: GLP-1 medicines for weight loss and diabetes — what you need to know (updated 5 February 2026) · MHRA news: women on weight-loss jabs must use effective contraception (5 June 2025) · NHS: tirzepatide (contraception, pregnancy, breastfeeding) · MHRA Yellow Card scheme
MediWatch is not medical advice. Always follow your prescription label and ask a pharmacist, GP, specialist, NHS 111, or emergency services if you are unsure or unwell. Data checked daily against official sources.