1.21. Analysis.
Comparison 1 Supplementation with vitamin D alone versus placebo or no intervention (no vitamins or minerals), Outcome 21 Preterm birth (less than 37 weeks' gestation) (by skin pigmentation based on Fitzpatrick skin tone chart).
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.