evaluation of the effect of high?dose folic acid on endothelial dysfunction in pre?eclamptic patients: a randomized clinical trial

background: pre?eclampsia as a hypertensive disorder of pregnancy complicates up to 5–10% of pregnancies worldwide. endothelial dysfunction plays an important role in the pathogenesis of pre?eclampsia. in this study, we aim to evaluate the effect of high?dose folic acid on endothelial dysfunction in pre?eclamptic patients. materials and methods: in this triple?blinded randomized clinical trial, the enrolled patients were divided randomly into two groups. folic acid 5.0 mg or placebo was taken daily by oral administration from the initiation of diagnosis until 2 months after delivery by the participants. every patient’s flow?mediated dilation (fmd) was evaluated at the beginning of the study and 2 months after delivery with the same experienced operator at the same period of time (3–5 p.m.) by high?resolution b?mode ultrasonography. potential confounding variables were included in the  independent samples t?test. t?test or mann–whitney u?test was used in the comparison of means between the intervention and placebo groups. to compare fmd in each group, before and after the intervention, paired t?test was used. results: mean value of fmd in intervention (9.64 ± 5.57) and control group (9.30 ± 4.25) has no significant difference before the consumption of drugs (p > 0.05). fmd in intervention group (13.72 ± 7.89) significantly increases after daily consumption of 5 mg folic acid in comparison with control group (10.02 ± 4.81) after daily consumption of placebo (p = 0.002). conclusion: increased mean of fmd in intervention group shows that this supplement can improve endothelial function and can be significantly affected by maternal blood pressure during pregnancy and some endothelium?dependent disease such as pre?eclampsia and its associated adverse outcomes.