UK: A new follow-up analysis from a randomized controlled trial has found that vitamin D supplementation during pregnancy can significantly enhance bone mineral density (BMD) and lean mass in children during mid-childhood.
The study, published in The American Journal of Clinical Nutrition, found that mothers who took 1000 IU per day of cholecalciferol, a form of vitamin D, saw notable improvements in their offspring's bone health compared to those who received a placebo.

Findings from the MAVIDOS trial showed that gestational cholecalciferol supplementation positively impacted offspring BMD at age 4. Establishing the persistence of this effect is crucial for evaluating whether maternal vitamin D supplementation could serve as an effective public health strategy to enhance bone health. Nicholas C. Harvey, Southampton General Hospital, Tremona Road, Southampton, UK, and colleagues aimed to examine whether gestational vitamin D supplementation boosts offspring bone mineral density at ages 6 to 7 in an exploratory post-hoc analysis of a previously conducted trial.
For this purpose, the researchers in the MAVIDOS randomized controlled trial studied pregnant women under 14 weeks along with a single baby and with serum 25-hydroxyvitamin D levels between 25-100 nmol/L at three hospitals in the UK (Southampton, Sheffield, and Oxford). These women were randomly assigned to receive either 1000 IU of cholecalciferol (vitamin D) or a placebo from 14 to 17 weeks of pregnancy until delivery.

Children born to participants in Southampton were invited for follow-up assessments at ages 4 and 6-7 years. During these visits, the children underwent dual-energy X-ray absorptiometry (DXA) scans to measure their bone health, including bone area, bone mineral content, bone mineral density (BMD), and bone mineral apparent density.
Linear regression was then used to compare results between the two groups, accounting for factors like age, sex, height, weight, breastfeeding duration, and vitamin D usage at 6-7 years.
The following were the key findings of the study:
Four hundred fifty-four children were followed up at age 6-7 years, of whom 447 had a usable DXA scan.
Gestational cholecalciferol supplementation resulted in higher WBLH BMC (0.15 SD), BMD (0.18 SD), BMAD (0.18 SD), and lean mass (0.09 SD) compared to placebo.
The effect of pregnancy cholecalciferol on bone outcomes was similar at ages 4 and 6-7 years.
According to the researchers, dual-energy X-ray absorptiometry (DEXA) scans show that vitamin D supplementation during pregnancy leads to higher bone mineral density in children up to age 7.
"These findings indicate that vitamin D supplementation during pregnancy could be a crucial public health strategy for enhancing bone health," the researchers concluded.
Reference:
Moon, R. J., Angelo, S. D., Curtis, E. M., Ward, K. A., Crozier, S. R., Schoenmakers, I., Javaid, M., Bishop, N. J., Godfrey, K. M., Cooper, C., & Harvey, N. C. (2024). Pregnancy vitamin D supplementation and offspring bone mineral density in childhood Follow-up of a randomised controlled trial. The American Journal of Clinical Nutrition. https://doi.org/10.1016/j.ajcnut.2024.09.014