Scientists from Spain, the USA, and Peru report that newborns of mothers who took vitamin D supplements during pregnancy were 108 grams heavier and 0.3 cm longer than newborns from mothers who did not take the D supplements.
“This systematic review and meta-analysis of RCTs showed a significant increase in circulating 25(OH)D in pregnant women who received vitamin D supplementation,” wrote the authors in Fertility and Sterility.
“Birth weight and birth length were slightly but significantly greater in the neonates of mothers who received vitamin D supplements, compared with those who did not.”
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. Both D3 and D2 precursors are transformed in the liver and kidneys into 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D).
Vitamin D deficiency in adults is reported to precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases.
The new meta-analysis, led by Faustino Perez-Lopez, MD, PhD, from the University of Zaragoza Faculty of Medicine and Lozano Blesa University Hospital, also indicates potential benefits of maternal supplementation for newborns.
The researchers identified 13 randomized controlled trials that met their inclusion criteria. These trials provided data on 2,299 newborns. The data indicated that vitamin D supplementation was associated with slight but significant increases in birth weight and length (see figure below).
No differences between the vitamin D and no vitamin D groups were observed for the incidence of pre-eclampsia, gestational diabetes, and preterm birth, added the researchers.
“Fetal growth is a complex process dependent on many factors, including genetic background, birth interval, trophoblast implantation, placental development, nutrition, and physical activity,” wrote the researchers. “Thus, vitamin D may play a minor role in fetal growth, compared with other factors.
“Fulfilling at least the recommended dietary allowance of 600 IU per day seems reasonable, until more-robust evidence is available that higher daily doses of vitamin D are beneficial. Even this minimal amount of vitamin D (600 IU per day) is not received by many pregnant women worldwide,” they concluded.
Source: Fertility and Sterility
Published online ahead of print, doi: 10.1016/j.fertnstert.2015.02.019
“Effect of vitamin D supplementation during pregnancy on maternal and neonatal outcomes: a systematic review and meta-analysis of randomized controlled trials”
Authors: F.R. Perez-Lopez, V. Pasupuleti, E. Mezones-Holguin, et al.