Next-generation Effects of Vitamin D Supplementation in Pregnancy

Vitamin D deficiency is common among Danish pregnant women, although most pregnant women adhere to guidelines of a daily supplement of 10 µg vitamin D. Vitamin D deficiency increases the risk of complications in the pregnancy e.g., preeclampsia, gestational diabetes mellitus and fetal growth retardation. Several studies indicate that the offspring has an increased risk of immune diseases e.g., asthma and autoimmune related diseases e.g., multiple sclerosis if the mother had vitamin D deficiency during the pregnancy. It is well known that vitamin D affects the immune system, which raises the question of the effects of vitamin D supplements and which doses to give optimally.

This study aims to investigate if maternal vitamin D intake of 90 vs 10 µg D3 affects the overall health, growth, and immune system of the offspring at birth and after 1 year. Blood samples at birth and after 1 year, questionnaires and clinical 1-year examination will be performed on the children. The hypothesis is that increased vitamin D supplementation in pregnancy improves fetal development including the offspring's immune system and the developing brain. The effects of vitamin D supplementation will strengthen the offspring's overall health at birth and during their first year of life. Hopefully, this can, in the future, be part of a guideline to which dose of vitamin D is recommended for Danish pregnant women.