Tirzepatide (Mounjaro) and contraception/pregnancy

GLP-1 agonists and contraception

What are GLP-1 agonists?

GLP-1 agonists include medications such as tirzepatide and semaglutide which may be better known by their different brand names (see below). They are prescription only medications that may be prescribed by a qualified healthcare professional for people with type two diabetes, or to facilitate weight loss. One of the main ways they work is by slowing the rate at which food leaves the stomach (delayed gastric emptying).#

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 you should use a barrier method of contraception (e.g. condoms) in addition to your pill for four weeks after starting the medication, and for four weeks after any increase in dose. This is because tirzepatide works slightly differently to the other GLP-1 agonists. Alternatively, you may wish to consider another (non-oral) method of contraception whilst using tirzepatide.

There is currently no evidence that semaglutide, exenatide, liraglutide, dulaglutide or lixisenatide reduce the effectiveness of oral contraception (i.e. the combined pill, or the progestogen only pill/ “mini-pill”).

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

Diarrhoea and vomiting are common side effects of the GLP-1 agonists and can reduce the effectiveness of the pill. If vomiting occurs within three hours of taking the contraceptive pill, or severe diarrhoea occurs for more than 24 hours, you should follow the guidance for missed pills. You should consider an alternative non-oral method of contraception or the addition of condoms if diarrhoea or vomiting persists.

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

There is no reason to believe that GLP-1 agonists affect methods of contraception that are not taken by mouth, so it is okay to use any of these options. No extra precautions are needed when using these methods of contraception alongside 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 switching to tirzepatide from ANY other GLP-1 agonist then you should use a barrier method of contraception (such as a condom) for four weeks after the switch, and for four weeks after any increases in dose, while also continuing your oral contraception. Alternatively, you may wish to consider changing to a non-oral method of contraception whilst using tirzepatide.

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

We don’t know yet if oral emergency contraception is affected by GLP-1 agonists. The copper IUD (coil) is the most effective method of emergency contraception and is not affected by diarrhoea and vomiting. If you require emergency contraception, please tell your healthcare practitioner about all other medications you are taking, including GLP-1 agonists.

Can I take a GLP-1 agonist during pregnancy

It is important to use effective contraception whilst taking a GLP-1 agonist, as these medications should not be used in pregnancy. If you become pregnant whilst taking one of these medications it is important to discuss this with your doctor. GLP-1 agonists should also be avoided for a number of weeks prior to a planned pregnancy. The table below shows the number of weeks recommended to have stopped the medication prior to a planned pregnancy (washout period), for some of the GLP-1 agonists.

Published: Mar 4, 2025