Effect of Folic Acid Supplementation in Pregnancy on Preeclampsia: The Folic Acid Clinical Trial Study

Multicenter randomized placebo-controlled trial in pregnant women at high risk for preeclampsia, conducted in Canada with international collaboration. Allocation was 1:1, and the active folic acid arm planned to enroll 1,532 participants.

Oral folic acid 4.0 mg once daily, started at randomization in early pregnancy (8 0/7 to 16 6/7 weeks gestation) and continued until delivery, compared with placebo. Participants could also receive routine prenatal folate supplementation, but the active study regimen was folic acid 4.0 mg/day.

No final efficacy results are reported in this packet because it describes the trial design rather than completed outcomes. The trial was designed to test whether daily folic acid 4.0 mg could reduce preeclampsia by about 30% (from 12% to 8.4%) in high-risk pregnancies. As of June 15, 2013, 450 participants had been randomized. The authors concluded there was no major safety concern with folic acid supplementation in pregnancy and that testing this regimen was justified.

This packet provides a study protocol and recruitment update rather than completed outcome data, so treatment efficacy cannot be assessed. Recruitment was ongoing, with only 450 participants randomized at the time described, and the findings are limited to high-risk pregnant women. The active arm sample size was planned, not achieved in the provided source.