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Pregnancy, breastfeeding and fertility while taking cefalexin - Brand name: Keflex

Cefelaxin and pregnancy

You can take cefalexin at any stage during pregnancy. There's no evidence that it causes harm to the baby.

It's important to treat infection during pregnancy as there's a risk that it could make you unwell if left untreated.

Cefelaxin and breastfeeding

It's OK for you to take cefalexin while breastfeeding.

Only tiny amounts of cefalexin get into breast milk, so it does not normally cause any side effects in your baby. However, it has caused diarrhoea in a few infants.

It's important to treat an infection while you're breastfeeding as there's a risk that it could make you unwell if left untreated.

Talk to your health visitor, midwife, doctor or pharmacist as soon as possible if you have any concerns, including if your baby:

  • is not feeding as well as usual
  • has sickness or diarrhoea
  • has oral thrush (a fungal infection in their mouth) or a skin rash

Cefelaxin and fertility

There's no evidence to suggest that cefalexin affects fertility in men or women.

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

  • trying to get pregnant
  • pregnant
  • breastfeeding

Find out more about how cephalosporin antibiotics like cefalexin can affect you and your baby on the Best Use of Medicines in Pregnancy (BUMPS) website.

Page last reviewed: 5 April 2023
Next review due: 5 April 2026