3.2. Intervention Trials
3.2.1. Studies Showing Correlation between Maternal and Foetal Vitamin D Status
Five hundred and six pregnant women were given 400 IU (10µg) of vitamin D per day from about the 12th week of pregnancy until delivery. A control group of 633 pregnant women was given a placebo. Maternal vitamin D was measured at the 24th and 34th weeks of pregnancy and at delivery and infant vitamin D was measured in umbilical blood at birth and on the sixth day following birth. Plasma concentrations of 25(OH)D, which showed a seasonal variation, was higher in mothers and infants in the treated group. Cord-blood 25(OH)D correlated with maternal values at delivery. A defect of dental enamel was found in a high proportion of infants (many of whom had suffered from hypocalcaemia) born to the control women. These results suggest that vitamin D supplementation during pregnancy would be beneficial for mothers, whose intake from diet and skin synthesis is appreciably less than 500 IU of vitamin D daily.