Results
A total of 10,154 women underwent randomization. The two groups were similar
with respect to baseline characteristics and adherence to the study drug. Outcome
data were available for 9969 women. There was no significant difference between
the vitamin and placebo groups in the rates of the primary outcome (6.1% and 5.7%,
respectively; relative risk in the vitamin group, 1.07; 95% confidence interval [CI],
0.91 to 1.25) or in the rates of preeclampsia (7.2% and 6.7%, respectively; relative
risk, 1.07; 95% CI, 0.93 to 1.24). Rates of adverse perinatal outcomes did not differ
significantly between the groups.