Mounjaro and Foundayo may make the contraceptive pill less reliable, so add condoms or use a non-oral method for 4 weeks (Mounjaro) or 30 days (Foundayo) after starting and after each dose increase. Wegovy injections and Wegovy tablets do not affect the pill in a way that matters, unless you have severe vomiting or diarrhoea. None of these medicines can be used in pregnancy, and each must be stopped a set time before trying for a baby: at least 1 month for Mounjaro, 2 months for Wegovy and 3 weeks for Foundayo.
This guide sets out what the UK product information and the MHRA say for each medicine, how long to stop before trying for a baby, breastfeeding, and what to do if things do not go to plan.
It covers Mounjaro (tirzepatide), Wegovy injections and Wegovy tablets (semaglutide), and Foundayo (orforglipron). All four are covered on our weight loss treatment page, and every question women ask us about them is gathered on our page on women's health on weight-loss treatment.
Does each GLP-1 medicine affect the pill?
| Medicine | If you take the contraceptive pill | Stop before trying for a baby |
|---|---|---|
| Mounjaro, weekly injection | Can make the pill less reliable. Add condoms or use a non-oral method for 4 weeks after starting and 4 weeks after each dose increase | At least 1 month |
| Wegovy, weekly injection | No extra precautions, unless you have severe vomiting or diarrhoea | At least 2 months |
| Wegovy tablets, once daily | No extra precautions. Take your pill at least 30 minutes after the Wegovy tablet | At least 2 months |
| Foundayo, once daily tablet | May make the pill less reliable. Add condoms or use a non-oral method for 30 days after starting and 30 days after each dose increase | At least 3 weeks |
Whichever medicine you take, the MHRA asks anyone who could become pregnant to use contraception throughout treatment and for the whole time between stopping and trying to conceive.
Can you take Wegovy or other GLP-1 medicines while pregnant?
The MHRA says GLP-1 medicines should not be taken during pregnancy, when trying to get pregnant or while breastfeeding. There is not yet enough safety information to know whether they could harm a baby, and some animal studies found harm to the unborn young, although it is not known whether the same would happen in people. So the answer is no, and the advice is to avoid pregnancy while you take them, and for a set time after you stop.
There is a second reason to plan ahead. If you have found it hard to get pregnant in the past, for example with polycystic ovary syndrome (PCOS), do not rely on that as contraception now. The UK product information says the effect of these medicines on fertility is not known, and Mounjaro and Foundayo can make the pill less reliable at times. Our guides to Mounjaro and fertility and Mounjaro and PCOS explain more.
Does Mounjaro stop the pill working?
It can make it less reliable for a while. Mounjaro slows down how quickly your stomach empties, which changes how tablets taken by mouth are absorbed. In a study of a combined pill taken with a single 5mg dose of Mounjaro, the peak levels of the pill's two hormones fell by more than half and the total amount absorbed by about a fifth. That is why the advice focuses on the weeks after you start and after each dose increase.
The UK product information says no change is needed for people at a healthy weight, but for people who are overweight or living with obesity, which includes everyone prescribed Mounjaro for weight loss, the advice is clear. This is the counselling every Mounjaro patient receives from us:
Contraception (Mounjaro only): tirzepatide can reduce absorption of the contraceptive pill. Use a non-oral method or add condoms for 4 weeks after starting and for 4 weeks after each dose increase. Wegovy needs no extra precautions unless severe vomiting or diarrhoea occurs, then follow missed-pill guidance.
We give the same advice for the progestogen-only pill (the mini pill) as for the combined pill, because both are taken by mouth, although the study used a combined pill. In practice, Mounjaro doses go up in steps of at least 4 weeks during the first months of treatment. If your dose rises every 4 weeks, those 4 week windows run straight into each other, so many people find it simplest to use condoms throughout the time their dose is going up, or to move to a non-oral method before they start.
Does Wegovy affect the pill?
No, not in a way that matters. In studies, semaglutide, the medicine in Wegovy, did not change the levels of the pill's hormones to a clinically relevant degree, and the UK product information says it is not expected to make the pill less effective. The Faculty of Sexual and Reproductive Healthcare (FSRH) says there is no need to add a barrier method with semaglutide, so no extra precautions are needed.
The exception is being unwell. Sickness and diarrhoea are very common side effects of Wegovy, especially while the dose is going up, and if you are sick soon after taking your pill, or have diarrhoea for more than a day, less of the pill may be absorbed. For the combined pill, the NHS advice is:
- If you are sick less than 3 hours after taking your pill (4 hours for Qlaira or Zoely), take another one straight away, then the next one at the usual time.
- If you keep being sick, use condoms as well until you have taken your pill for 7 days without being sick.
- If you have diarrhoea for more than 24 hours, keep taking your pill as normal and use condoms until 7 days after the diarrhoea stops.
Progestogen-only pills have their own timings, so check the leaflet in your pill packet. The same advice applies to every medicine in this guide.
Do Wegovy tablets affect the pill?
Wegovy tablets contain the same medicine as the injection, and the UK product information again found no clinically relevant change in the pill's hormones. The one practical point is timing. The Wegovy tablet is taken on an empty stomach, and you then wait at least 30 minutes before eating, drinking or taking any other medicine by mouth, because waiting less than 30 minutes lowers how much of the Wegovy tablet is absorbed. Your contraceptive pill is one of those medicines, so take it at least 30 minutes after your Wegovy tablet, or at another time of day. Our guide on how to take the Wegovy pill explains the 30 minute rule.
Does Foundayo affect the pill?
Yes, it may. The UK product information says Foundayo may reduce how well oral hormonal contraceptives work, and that anyone who could become pregnant should use effective contraception while taking it. The counselling we give is:
If you use the oral contraceptive pill, use a non-oral method or add a barrier method such as condoms for 30 days after starting treatment and for 30 days after each dose increase.
Foundayo doses also go up in steps of at least 30 days, so, as with Mounjaro, these windows can run into each other while your dose is rising. For more on taking it, see how to take Foundayo.
Which contraception is not affected?
Methods that do not rely on being absorbed from your stomach are not affected in the same way. The MHRA names the coil and the implant, and the FSRH also lists the contraceptive injection, the patch and the vaginal ring as non-oral options. These include:
- the implant in your arm
- the copper coil (IUD) or the hormonal coil (IUS)
- the contraceptive injection
- the patch
- the vaginal ring
Not every method works from the day it is started, so if you are switching, ask your GP, a sexual health clinic or the leaflet for your new method when you are covered, and use condoms until then. Condoms are the barrier method the guidance refers to: they work alongside any pill.
How long before trying for a baby should you stop?
These medicines stay in your body for some time after the last dose, so each has a minimum gap between stopping and trying to conceive. Keep using contraception throughout that gap.
- Mounjaro: at least 1 month
- Wegovy injections and Wegovy tablets: at least 2 months
- Foundayo: at least 3 weeks
For the injections, the counselling we give every patient reads:
Pregnancy: these medicines must not be used in pregnancy. Stop and contact us or your GP immediately if you become pregnant. If planning pregnancy: stop Mounjaro at least 1 month before, Wegovy at least 2 months before.
Tell us as soon as you start planning a pregnancy, rather than stopping and trying straight away. Some weight can return when treatment stops, so it helps to plan the timing with us and your GP, and to keep up the eating and activity habits that have worked for you. Our guide to what happens when you stop taking Mounjaro explains what to expect.
What if you become pregnant while taking a GLP-1 medicine?
Stop taking it, and speak to your GP or prescriber straight away. Then let us know, so we can stop any further supply. Your GP or midwife will advise you from there. If you think a medicine has caused a problem, you or your doctor can report it through the MHRA Yellow Card scheme. More in Mounjaro and pregnancy.
Can you take GLP-1 medicines while breastfeeding?
The MHRA's advice is that GLP-1 medicines should not be taken while breastfeeding, and the UK product information for Wegovy, Wegovy tablets and Foundayo says the same. The Mounjaro product information now includes a small study that found very low or undetectable levels in breast milk, but the MHRA's guidance has not changed, and we follow it. We do not supply any weight loss medicine to someone who is breastfeeding. More in Mounjaro and breastfeeding.
How does Solira check this before you start?
Our consultation asks whether you are pregnant, breastfeeding or actively trying to conceive, and we cannot supply weight loss medicines, injections or tablets, if you are. It also asks whether you take the contraceptive pill, and before you pay, you read and agree to the pregnancy and contraception advice for the medicine you have chosen. A GPhC-registered pharmacist then reviews every consultation.
If you would like to see whether treatment is right for you, the consultation is free and takes a few minutes: check if you are eligible. To compare the medicines first, see our weight loss treatments.