Vitamin D Requirement During Pregnancy May Be Higher Than Previously Thought


This study included 600 women of diverse backgrounds including African Americans, Hispanics, and whites. It was important to include multiple races in the study because skin pigmentation reduces the absorption of vitamin D from sunlight. The women were separated into 3 groups: a control group who took the recommended 400 IU found in most prenatals; a group that took 2000 IU of vitamin D; and a group that took 4,000 IU of vitamin D (ten times the standard recommendation).

Key points from the study:

  • Women taking the 4,000 IU increased their vitamin D levels to a normal 40 ng/mL, a 50% increase from baseline
  • In those taking the 4,000 IU premature births and premature labor were reduced by 50%, and fewer babies were born small for gestational age (SGA is a well-known complication related to inadequate vitamin D).
  • Women in the 2,000 IU and 4,000 IU groups had a 50% reduction in infections throughout pregnancy, including respiratory, vaginal and periodontal infections.
  • Women in the higher supplemented groups had 30% fewer complications such as gestational diabetes, hypertension and pre-eclampsia.
  • Infants born to women taking the 4,000 IU supplements had fewer colds and less eczema.

It will likely take years before the academic pediatric and obstetric associations modify their recommendations to reflect the study’s high level of supplementation. In fact, before beginning this study, Dr. Hollis had to first get FDA approval in order to use 4000 IUs of vitamin D as an “investigational drug”. This is the first study to get approval for use of 4,000 IU (the current UL) during pregnancy and the results are very important. Previous research had shown that moms who took the recommended 400 IU/day vitamin D in their prenatal vitamin and drank 2.3 glasses of milk a day did not attain a normal vitamin D level–at birth, 76% of moms were vitamin D deficient–81% of newborns were deficient.