GLP-1 agonists (e.g. Mounjaro) and Contraception or HRT

Important ⚠️

Please read the information below carefully if you are using both a GLP-1 agonist, such as Mounjaro, and a Contraceptive or HRT. If you feel this applies to you or would like to discuss further, please contact the surgery.

What are GLP-1 agonists?

GLP-1 agonists are medicines like tirzepatide and semaglutide. They might have other brand names too such as Mounjaro, Ozempic or Wegovy. You may currently be prescribed one of these on the NHS for type 2 diabetes, or are purchasing it privately for weight loss.

These medicines are very effective — but they can affect how your body absorbs other medicines taken by mouth. This means any oral medications may not work as well or be reliable.

🚫 GLP-1 Medicines & The Pill (Oral Contraceptives)

GLP-1 medicines slow down how quickly your stomach empties. They can also cause diarrhoea and vomiting.

This can mean your body doesn’t absorb the pill as well — reducing how effectively it prevents pregnancy.

When is this most important?
🗓️ First 4 weeks after starting your GLP-1 medicine
🗓️ 4 weeks after any dose increase

What should you do?
✔️ Use a backup method of contraception (like condoms) for at least 4 weeks after starting or increasing your GLP-1 medicine ( For Tirzepatide/Mounjaro only)

✔️ If you have significant diarrhoea or vomiting with any GLP-1 medication then use condoms with your pill and follow the missed pill rules

✔️ Talk to your doctor or advanced nurse practitioner or contraceptive provider about your options – you may wish to consider a non-oral form of contraception during treatment

🔎 This guidance comes from the UK’s MHRA (Medicines and Healthcare products Regulatory Agency) as well as advice from FRSH ( Faculty of Reproductive and Sexual Health – now College of Reproductive and Sexual Health)

🌡️ GLP-1 Medicines & HRT

If you’re taking HRT for menopause symptoms, delayed stomach emptying can affect how well your body absorbs the hormones.

This could mean your HRT isn’t as effective if you are taking oral oestrogen/progesterone ( combined HRT tablets)

OR  

significantly, that the oral progesterone ( e.g utrogestan, medroxyprogesterone, nortethisterone) you are taking to keep the womb healthy may not be able to work as it should

If you do not take your HRT orally (for example, you use a patch, a gel/spray or a Mirena coil instead of a tablet) then you do not need to worry.

While there’s no specific MHRA warning yet about HRT, the British Menopause Society and FRSH have both urged caution and advised women to have their oral HRT treatment reviewed by their healthcare provider.

What should you do?

✔️ Talk to your doctor, advanced nurse practitioner or menopause specialist.

✔️ Ask about non-oral HRT options like patches, gels, sprays, or implants, which bypass your stomach and are not affected.

✔️ Keep an eye on your symptoms and seek medical advice if they return or if you get unscheduled bleeding.

Further Information:

For more detailed guidance, speak to your healthcare provider.

Missed pill calculator for advice on contraceptive management

FRSH patient information leaflet https://www.cosrh.org/Common/Uploaded%20files/documents/Patient-information-GLP-1-agonists-and-contraception.pdf

Detailed FAQs on GLP-1 plus Contraception/HRT

I am taking the pill. Will using a GLP-1 agonist affect my contraception?

This depends on the type of GLP-1 agonist that you are using.

If you are using tirzepatide (Mounjaro), you should use condoms along with your pill for four weeks after you start the medicine and for four weeks after any dose increase. This is because tirzepatide works a bit differently from other similar medicines. You might also think about using a different type of contraception that isn’t a pill while on tirzepatide.

For other medicines like semaglutide, exenatide, liraglutide, dulaglutide, or lixisenatide, there is no proof that they make the pill less effective UNLESS they give you diarrhoea or vomiting in which case they can.

I have diarrhoea and vomiting with my GLP-1 agonist, and I take the contraceptive pill, what should I do?

Diarrhoea and vomiting can happen when taking GLP-1 agonists and might make the pill less effective. If you vomit within three hours of taking your pill, or have bad diarrhoea for more than a day, follow the guidance for missed pills. If diarrhoea or vomiting continues, think about using a different type of contraception that isn’t a pill, or use condoms as well.

What about non-oral methods of contraception e.g. the coil, implant, injection, patch or ring, could these be affected by GLP-1 agonists?

GLP-1 agonists do not affect contraception methods that aren’t pills. So, it’s safe to use these other options without any extra precautions when taking a GLP-1 agonist.

I am planning to switch from one type/brand of GLP-1 to another, does the contraception advice remain the same?

If you are changing to tirzepatide (Mounjaro) from any other GLP-1 agonist, use condoms for four weeks after switching and for four weeks after any dose increase. Keep taking your pill too. Or, you might want to switch to a different type of contraception that isn’t a pill while using tirzepatide.

I need emergency contraception and I’m taking a GLP-1 agonist; will it work?

We don’t know yet if GLP-1 agonists affect emergency contraception pills. The copper IUD (coil) is the best emergency contraception and isn’t affected by diarrhoea or vomiting. If you need emergency contraception, tell your healthcare provider about all the medicines you’re taking, including GLP-1 agonists.

Can I take a GLP-1 agonist during pregnancy?

These medicines shouldn’t be used if you’re pregnant. If you get pregnant while on these medicines, talk to your doctor. You should also stop taking GLP-1 agonists several weeks before trying to get pregnant. The table below shows how many weeks you should stop the medicine before planning a pregnancy for some GLP-1 agonists.

These medicines are also not recommended when breastfeeding.

I’m on HRT and taking Mounjaro – what do I need to know?

If you are taking oral progestogen as part of your HRT (for example Utrogestan, Norethisterone, Medroxyprogesterone), then you need to be aware that tirzepatide (Mounjaro) may have an impact on the effectiveness of your HRT. This means your HRT might not protect your endometrium (womb lining) enough. Please contact the surgery to book an HRT review, as we may need to increase your dose or change you to a different form of medication.