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.
1991 MRC trial on prevention of neural tube defects (NTDs) with folic acid 4000 mcg daily with/without multivitamins versus placebo with/without multivitamins.4
*An informative pregnancy was one in which the fetus or infant was known to have or not have a neural tube defect by the time the trial was stopped.
