Comparison of high dose and low dose folic acid supplementation on prevalence, onset and severity of preeclampsia

Preventive effects of folic acid on Zika virus-associated poor pregnancy outcomes in immunocompromised mice

Zika virus (ZIKV) infection may lead to congenital microcephaly and pregnancy loss in pregnant women. In the context of pregnancy, folic acid (FA) supplementation may reduce the risk of abnormal pregnancy outcomes. Intriguingly, FA may have a beneficial effect on the adverse pregnancy outcomes associated with ZIKV infection. Here, we show that FA inhibits ZIKV replication in human umbilical vein endothelial cells (HUVECs) and a cell culture model of blood-placental barrier (BPB). The inhibitory effect of FA against ZIKV infection is associated with FRα-AMPK signaling. Furthermore, treatment with FA reduces pathological features in the placenta, number of fetal resorptions, and stillbirths in two mouse models of in utero ZIKV transmission. Mice with FA treatment showed lower viral burden and better prognostic profiles in the placenta including reduced inflammatory response, and enhanced integrity of BPB. Overall, our findings suggest the preventive role of FA supplementation in ZIKV-associated abnormal pregnancy and warrant nutritional surveillance to evaluate maternal FA status in areas with active ZIKV transmission.

Effect of high dose folic acid supplementation in pregnancy on pre-eclampsia (FACT): double blind, phase III, randomised controlled, international, multicentre trial

OBJECTIVE

To determine the efficacy of high dose folic acid supplementation for prevention of pre-eclampsia in women with at least one risk factor: pre-existing hypertension, prepregnancy diabetes (type 1 or 2), twin pregnancy, pre-eclampsia in a previous pregnancy, or body mass index ≥35.

DESIGN

Randomised, phase III, double blinded international, multicentre clinical trial.

SETTING

70 obstetrical centres in five countries (Argentina, Australia, Canada, Jamaica, and UK).

PARTICIPANTS

2464 pregnant women with at least one high risk factor for pre-eclampsia were randomised between 2011 and 2015 (1144 to the folic acid group and 1157 to the placebo group); 2301 were included in the intention to treat analyses.

INTERVENTION

Eligible women were randomised to receive either daily high dose folic acid (four 1.0 mg oral tablets) or placebo from eight weeks of gestation to the end of week 16 of gestation until delivery. Clinicians, participants, adjudicators, and study staff were masked to study treatment allocation.

MAIN OUTCOME MEASURE

The primary outcome was pre-eclampsia, defined as hypertension presenting after 20 weeks' gestation with major proteinuria or HELLP syndrome (haemolysis, elevated liver enzymes, low platelets).

RESULTS

Pre-eclampsia occurred in 169/1144 (14.8%) women in the folic acid group and 156/1157 (13.5%) in the placebo group (relative risk 1.10, 95% confidence interval 0.90 to 1.34; P=0.37). There was no evidence of differences between the groups for any other adverse maternal or neonatal outcomes.

CONCLUSION

Supplementation with 4.0 mg/day folic acid beyond the first trimester does not prevent pre-eclampsia in women at high risk for this condition.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN23781770 and ClinicalTrials.gov NCT01355159.