Skip to main content

Pregnancy, breastfeeding and fertility while taking or using metronidazole - Brand names: Acea, Flagyl, Rozex

Metronidazole and pregnancy

You may be able to use metronidazole while you're pregnant.

If you're trying to get pregnant or you're already pregnant, talk to your doctor about whether taking metronidazole is right for you.

Metronidazole and breastfeeding

If your baby is healthy, it's OK to take metronidazole while you're breastfeeding. Always check with a pharmacist or doctor before taking it.

When metronidazole is taken by mouth, or as suppositories, or injected, it passes into breast milk in fairly small amounts. It has been widely used for many years while breastfeeding and it's unlikely to cause side effects in your baby, but a few babies have had diarrhoea.

It's best to take metronidazole only for a short time. If you need to take it for longer than a few weeks, talk to your doctor or pharmacist.

When metronidazole is used on your skin, or as a vaginal gel, it is not likely to get into your breast milk, and you can use it for longer than a few weeks if you need to.

When using the cream or gel, be careful that your baby does not come into contact with the areas of your body you have put it on. Always wash your hands after you have applied the cream, gel or vaginal gel before touching your baby.

It's important to keep monitoring your baby if you're breastfeeding and taking metronidazole by mouth, as suppositories, or as an injection.

Contact your healthcare professional or call 111 as soon as possible if you notice that your baby:

  • is not feeding as well as usual or not putting on weight as you'd expect
  • has a stomach upset
  • has oral thrush (a fungal infection in their mouth)

If your baby has any symptoms that are not listed, or if you're worried about them, you can also call 111 or contact any healthcare professional.

Carry on taking metronidazole and keep breastfeeding as usual until you've got advice about your baby's symptoms.

Metronidazole and fertility

There's no evidence that taking metronidazole affects fertility in either men or women.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding
Information:

Find out more about how metronidazole can affect you and your baby on the Bumps (Best Use of Medicines in Pregnancy) website.

Page last reviewed: 31 December 2025
Next review due: 31 December 2028