Meta-analysis: Gestational diabetes linked to low vitamin D[B]
Posted on July 26, 2012 by John Cannell, MD


Diabetes during pregnancy (gestational diabetes) occurs in about 10% of all pregnancies. It leads to higher Caesarean section rates, pre-eclampsia, birth complications, and infant distress syndrome. Later the child suffers from a higher risk of obesity and type-2 diabetes.




Dr. Y.H.M. Poel and colleagues from the Netherlands recently conducted the first ever meta-analysis of vitamin D levels and gestational diabetes (GD), finding seven studies that met their criteria. Overall, the risk of having GD was higher in women with lower vitamin D levels with an odds ratio of 1.6.

Poel YH, Hummel P, Lips P, Stam F, van der Ploeg T, Simsek S. Vitamin D and gestational diabetes: A systematic review and meta-analysis. Eur J Intern Med. 2012 Jul;23(5):465-9. Epub 2012 Feb 21.


What I found interesting was the corrections some of the studies used. One initially positive study used in the meta-analysis turned negative after the authors corrected for age, weight, season, and ethnicity. When one corrects for factors closely associated with vitamin D levels, such as age, weight, season, and ethnicity, one simply over-corrects away any findings. That is, all these factors are associated with GD, but they may be associated via a vitamin D mechanism. This means that correction for these factors is like correcting for vitamin D levels, a correction that will always result in a negative study.

My advice is that couples thinking of getting pregnant should each take 5,000 IU/day for a year before conception. Then both continue until the woman is in her third trimester, at which time she should increase to 6,000 IU/day, 5,000 for her and 1,000 for her rapidly growing baby.

After birth, the parents should continue 5,000 IU per day for the rest of their lives. If breastfeeding, the mother should go back up to 6,000 IU/day and the infant will get all the required vitamin D from her breast milk. If not breastfeeding, children require 1,000 IU/day for every 25 pounds of body weight, rounded up. Therefore, a 10-pound infant should take 1,000 IU/day.

Increasingly, it looks as if following these recommendations will lead to a lifetime of bad things not happening.