One of the most pressing needs the vitamin D community has is to identify and treat vitamin D deficient pregnant women. Professor Bruce Hollis has been at this issue for more than a decade and was recently senior author on a paper out of the University Teaching Hospital in the United Arab Emirates that looked at vitamin D supplementation during pregnancy. Doctor Adekunle Dawodu, from the Cincinnati Children’s Hospital Medical Center conducted the study.
Dawodu A, Saadi HF, Bekdache G, Javed Y, Altaye M, Hollis BW. Randomized Controlled Trial (RCT) of Vitamin D Supplementation in Pregnancy in a Population With Endemic Vitamin D Deficiency. J Clin Endocrinol Metab. 2013 Jun;98(6):2337-46.
The authors begin by noting:
“Inadequate maternal vitamin D status in pregnancy is associated with poor fetal growth and impaired bone development. Maternal vitamin D deficiency is associated with rickets and severe hypocalcemia in infants after birth in populations with a high prevalence of vitamin D deficiency. Low cord blood 25-hydroxyvitamin D [25(OH)D] is associated with increased risk of lower respiratory tract infections and infantile eczema in the first year of life. Furthermore, higher rates of preeclampsia, gestational diabetes and bacterial vaginosis are associated with low maternal vitamin D status during pregnancy, and vitamin D deficiency is associated with hypertension in observational and clinical studies.”
The authors identified about 160 pregnant women with very low 25(OH)D levels (mean 25(OH)D of 8.2 ng/mL) with 98% of them having 25(OH)D levels below 20 ng/ml. They split the women into three groups, treating each group – beginning during the 12-16th week of pregnancy – with either the traditionally recommended amount of 400 IU per day or 2,000 IU/day or 4,000 IU/day of vitamin D3.
The mean 25(OH)D levels of the women at birth was 36 ng/ml for the 4,000 IU group, 26 ng/ml for the 2,000 IU group and 19 ng/ml for the 400 IU group.
Mothers achieving 25(OH)D of at least 32 ng/mL was 82% in the 4,000 IU group, 24% in the 2,000 IU group, and only 10 % in the 400 IU/day group. Infants achieving 25(OH)D of at least 20 ng/mL was 75% in the 4,000 IU group, 47% in the 2,000 IU group and only 22% in the 400 IU/day group.
An interesting observation in this study was the average increase of almost 11 ng/ml in 25(OH)D levels in the 400 IU/day group, which was much higher than expected. Perhaps after being explained about vitamin D and pregnancy, the participants realized the importance of vitamin D during pregnancy and sought to get more on their own.
There were no significant differences in the mean birth weight, length, head circumference, or gestational age among groups. There were no differences between groups in safety measures such as blood calcium or urine calcium to creatinine ratios.
The authors concluded:
“Vitamin D supplementation of 4000 IU/d in this population appeared to be safe and most effective in achieving vitamin D sufficiency in mothers and serum 25(OH)D of 20 ng/mL or greater in infants at birth. Large randomized controlled trials are needed to test the safety and effectiveness of such supplementation strategy on growth and other nonskeletal health outcomes in the mother and offspring in populations with endemic vitamin D deficiency.”
I hope the authors will be following these infants to see if there are any developmental differences between groups.