Vitamin D in pregnancy

Vitamin D supplementation in pregnancy and breastfeeding

All women should be informed at the booking appointment about the importance for their own and their baby's health of maintaining adequate vitamin D stores during pregnancy and whilst breastfeeding.

• in order to achieve this, women should be advised to take a vitamin D supplement (10 micrograms of vitamin D per day (400 IU per day), as found in the Healthy Start multivitamin supplement

Women who are not eligible for the Healthy Start benefit should be advised where they can buy the supplement.

Particular care should be taken to enquire as to whether women at greatest risk are following advice to take this daily supplement. These include:

• women with darker skin (such as those of African, African-Caribbean or South Asian family origin
  
• women who have limited exposure to sunlight, such as women who are housebound or confined indoors for long periods, or who cover their skin for cultural reasons

NHS Specialist Pharmacy Service guidance with respect to vitamin D supplementation in breastfeeding states (3):

• Forms of vitamin D used during breastfeeding
  • vitamin D is available in many different forms
    • Colecalciferol (vitamin D3) or ergocalciferol (vitamin D2) are the two main vitamin D compounds used for the treatment and prevention of vitamin D deficiency
    • general guidance on the Safety considerations when using Vitamin D is available.
    • for other forms of vitamin D (including alfacalcidol, calcipotriol, and calcitriol), please contact specialist service for further advice
      
• With respect to doses of vitamin D in breastfeeding
  • prevention/supplement doses (usually 400 units daily)
  • maintenance doses (up to 4000 units daily) where treatment of vitamin D deficiency is not considered urgent or maintenance therapy is required. maintenance doses up to 4000 units daily can be used during breastfeeding and do not require any infant monitoring
  • loading doses (above 4000 units daily) where the treatment of vitamin D may require rapid correction
    • will usually not exceed a cumulative total dose of 300, 000 units divided into daily or weekly dosing over a maximum of 10 weeks
    • loading doses can be administered as various dosing schedules; examples include 50,000 units once weekly for 6 weeks, or 4000 units daily for 10 weeks
      
• Considerations for infant monitoring if maternal vitamin D supplementation:
  • infant monitoring side effects are generally not expected in breastfed infants, and therefore no specific infant monitoring is required when maintenance doses up to 4000 units daily are being used
    • however, as a precaution, monitor the infant for any unusual sign or symptoms
    • when loading doses are being used, the infant should be monitored for signs of hypercalcaemia as a precaution, including increased wet nappies, lethargy, gastro-intestinal disturbances, and changes in feeding
      • infant should also be monitored for irritability and skin reactions
      • infant calcium levels should be monitored if:
        • hypercalcaemia is suspected due to infant symptoms
        • loading doses above 300,000 units as the total treatment course are required
        • treatment courses longer than 10 weeks are required.

For detailed advice then see NHS Specialist Pharmacy Service - Using vitamin D during breastfeeding

Notes:

• a systematic review concluded that "..Supplementing pregnant women with more than the current vitamin D recommendation may reduce the risk of gestational diabetes; however, it may make little or no difference to the risk of pre-eclampsia, preterm birth and low birthweight. Supplementing pregnant women with more than the current upper limit for vitamin D seems not to increase the risk of the outcomes evaluated..." (2)

Reference:

• NICE (December 2018). Antenatal care for uncomplicated pregnancies
• Palacios C et al. Regimens of vitamin D supplementation for women during pregnancy. Cochrane Systematic Review October 2019
• NHS Specialist Pharmacy Service (December 2023). Using vitamin D during breastfeeding