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Pregnancy, breastfeeding and fertility while taking alendronic acid - Brand names: Fosamax, Binosto

Alendronic acid and pregnancy

Alendronic acid is not recommended during pregnancy. This is because there has not been enough research into its safety.

Alendronic acid and breastfeeding

It's usually OK to take alendronic acid while breastfeeding. Talk to your doctor or pharmacist first, and they will help you to decide.

It's not known how much alendronic acid gets into breast milk, but it's likely to be very low levels. Not a lot of it will pass through to your baby, so it's unlikely to cause them any side effects.

It's very rare for breastfed babies to have side effects from medicines you're taking. But it's important to keep monitoring your baby if you're taking any medicine while breastfeeding.

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

  • not feeding as well as usual
  • being irritable
  • being sick (vomiting) or has diarrhoea
  • constipated

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 the medicine, and keep breastfeeding as usual until you've got advice about your baby's symptoms.

Alendronic acid and fertility

There's no evidence to suggest that taking alendronic acid reduces fertility in either men or women.

However, if you're trying to get pregnant, speak to a pharmacist or your doctor. This is because you'll usually need to stop taking alendronic acid before getting pregnant.

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

  • trying to get pregnant
  • pregnant
  • breastfeeding

Page last reviewed: 7 May 2025
Next review due: 7 May 2028