Women's health

Women of childbearing potential should use contraception while taking Mounjaro or Wegovy.

The two medications differ in how they interact with the oral contraceptive pill, so it's important to know which applies to you.

• If you're taking Wegovy: Wegovy does not affect the effectiveness of the oral contraceptive pill. You can use birth control methods like the oral contraceptive pill, an IUD, an implant or a barrier method like condoms to avoid an unplanned pregnancy.
• If you're taking Mounjaro: Mounjaro impacts how your body absorbs the oral contraceptive pill because it slows down digestion. You must use a non-oral birth control method like an IUD or implant, or add a barrier method like condoms, to avoid an unplanned pregnancy.

If you experience severe diarrhoea lasting over 24 hours, or vomiting within three hours of taking your oral contraceptive pill, you may need a repeat dose. Contact your GP or call 111 for advice if this occurs.

No. Do not take Mounjaro or Wegovy while pregnant.

If you are planning to become pregnant, the discontinuation timelines differ between the two medications.

• Wegovy: discontinue at least two months before trying to conceive
• Mounjaro: discontinue at least one month before trying to conceive

Some people taking Mounjaro or Wegovy may notice changes in their vaginal bleeding, and this can happen more often in those also using hormone replacement therapy (HRT).

This may occur because both medications slow down digestion, which can affect how your body absorbs hormone treatments — particularly HRT taken as tablets, especially oral progestogens. There don't appear to be the same issues with hormone patches or intrauterine devices like the Mirena coil. Weight loss and other body changes may also play a role.

This kind of bleeding is usually not serious, but it's important to tell your doctor if you experience new, heavy or ongoing bleeding. They can check for other causes and may suggest adjusting your HRT or carrying out further tests if needed.