A follow-up study of randomized controlled trial (MAVIDOS) depicted that administration of vitamin D (1000 IU daily) in pregnancy from 14 weeks of gestation to delivery resulted in greater  areal bone mineral density (aBMD) and a trend toward greater bone mineral content (BMC) in their children at four years of age. Investigators aimed to examine whether prenatal vitamin D supplementation elevates the offspring's bone mineralization in early chidhood (at 4 years of age).

Overall, 1123 females in early pregnancy with a baseline 25-hydroxyvitamin D level of 25-100 nmol/l were randomly segregated into 1000 IU/day cholecalciferol or matched placebo from fourteen weeks' gestation till delivery. At age 4 years, an evaluation of the offspring was done. Dual-energy x-ray absorptiometry and anthropometry were carried out. Out of 723 children, 564 (78.0%) children attended the four-year visit. Notably, 452 children underwent useable dual-energy X-ray absorptiometry.

Compared with placebo, maternal vitamin D supplementation resulted in a higher whole body less head (WBLH) aBMD in children, as depicted in Table 1:

In sex and age adjusted models, and for bone mineral content and lean mass, consistent associations were witnessed. Additionally, a favorable effect of maternal intervention on offspring lean mass was noted. However, no effect on fat mass was noted. Irrespective of the season of birth, effects were seen across the whole cohort.

Among children with reduced physical activity levels and low milk intake, maternal-child correlations were noted, with a greater effect size. Child body mass index, height, and weight were comparable to the maternal randomization group. Hence, maternal vitamin D supplementation in pregnancy has a valuable effect on offspring aBMD at age 4 years.