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Pregnancy, breastfeeding and fertility while taking colecalciferol - Brand names: Lamberts, Hux D3, Solgar, SunVit D3

Colecalciferol and pregnancy

It is recommended that you take a daily vitamin D (colecalciferol) supplement of 400IU throughout pregnancy. This will help you and your baby stay healthy.

Many pregnancy multivitamins already contain 400IU (10 micrograms) of vitamin D so if you're taking one of these, you will not need an extra vitamin D supplement. Check the packet to see what dose of vitamin D it contains.

If you have been diagnosed with vitamin D deficiency (where your blood levels of vitamin D are too low), your doctor or midwife may offer a higher dose of colecalciferol. Higher doses are also safe to take during pregnancy. This treatment is important to help protect your teeth and muscles, and make sure your baby develops strong bones and teeth.

You may need extra blood tests to make sure that you are taking enough vitamin D.

Colecalciferol and breastfeeding

You can take colecalciferol (vitamin D) while you are breastfeeding.

Vitamin D is a natural part of breast milk. When you take colecalciferol as a supplement or treatment, it passes into your breast milk in low amounts and helps your baby to stay healthy.

If you have been prescribed a very high dose of colecalciferol (over 6,000IU a day), your baby may need extra blood tests. This is to make sure they're not getting too much.

Babies up to the age of 1 year need 340IU to 400IU of vitamin D drops a day as a supplement. Unless you're taking very high doses of colecalciferol for long periods, it's still safe to give it to your baby, even though they are getting colecalciferol through breast milk. This ensures they are getting enough.

If your baby is having at least 500ml of formula milk a day, they do not need supplements as formula milk already has vitamin D added.

If you notice your baby is not feeding as well as usual, or you have any other concerns about your baby, contact your doctor, pharmacist, health visitor or midwife.

Colecalciferol and fertility

There's no evidence to suggest that taking colecalciferol reduces 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 vitamin D supplements such as colecalciferol can affect you and your baby during pregnancy on the Best Use of Medicines in Pregnancy (BUMPS) website.

Page last reviewed: 10 January 2023
Next review due: 10 January 2026