FACT Biomarker Subgroup Analysis

The Folic Acid Clinical Trial (FACT) was developed to conclusively determine the effect of high dose folic acid supplementation in pregnancy on the prevention of preeclampsia (PE) in a randomized controlled trial (RCT) design.

The primary objective of the FACT Biomarker Subgroup Analysis is to determine the folate status and its impact on risk for PE in a subgroup of women participating in FACT. Our secondary objectives are to:

i) To determine serum vitamin B6 and B12 status, modifiers of folate metabolism, and their impact on risk for PE in women participating in the FACT

ii) To determine plasma homocysteine status, a folate-responsive biomarker for PE risk, and its relationship with risk for PE in women participating in the FACT

iii) To determine the modifying effect of single nucleotide polymorphisms (SNPs) in key folate metabolic enzymes (MTHFR, MTHFD1, MTR) on PE risk in women participating in the FACT

iv) To determine the effect of folic acid supplementation and folate status on biomarkers of PE (sFLT, sENG, PlGF) and their association with PE risk in women participating in the FACT

Folate biomarker analyses will provide key information to identify modifiers of the response to folic acid treatment and elucidate the mechanism(s) underlying the relationship between folic acid treatment and PE risk. Folate status will vary in response to folic acid treatment depending on a number of factors including compliance in taking the study supplement, folate intake from the diet (natural folate and folic acid used for enrichment), vitamin B12 status, and genetic polymorphisms in enzymes involved in folate metabolism that have been shown to effect placental development/function. As such, variation in the response to folic acid treatment may account for differences in observed PE risk.

Folic acid supplementation may also reduce homocysteine, its related endothelial dysfunction and consequently reduce PE risk. In addition, homocysteine metabolism is dependent on vitamins B12 and B6, the deficiency of which can result in hyperhomocysteinemia. Thus, homocysteine, B12 and B6 will each be evaluated.

Lastly, it will be useful to assess biomarkers of placental health and PE risk (sFlt-1, sEng, PlGF) that are found in maternal circulation and determine their association with folate intake and status.

Individuals participating in FACT (NCT01355159) will be eligible to participate. FACT eligibility criteria are as follows:

Inclusion criteria

• Capability of subject to comprehend and comply with study requirements
• ≥ 18 years of age at time of consent
• Subject is taking ≤1.1 mg of folic acid daily at the time of randomization
• Live fetus (documented positive fetal heart prior to randomization)
• Gestational age between 8+0 and 16+6 weeks of pregnancy (Gestational age (GA) of subjects will be calculated based on the first day of the last menstrual period (LMP) or ultrasound performed before 12+6. If early ultrasound and LMP dates differ by ≤ 7 days, base GA estimate on LMP date; if > 7 days, use early < 12+6 ultrasound)
• Subject plans to give birth in a participating hospital site
• Pregnant subjects must fulfill at least one of the following identified risk factors for pre-eclampsia (PE):

• Pre-existing hypertension (documented evidence of diastolic blood pressure ≥ 90 mmHg on two separate occasions or at least 4 hours apart prior to randomization, or use of antihypertensive medication during this pregnancy specifically for the treatment of hypertension prior to randomization)
• Pre-pregnancy diabetes (documented evidence of Type I or type II DM)
• Twin pregnancy
• Documented evidence of history of PE in a previous pregnancy
• BMI > 35 kg/m2 within 3 months prior to this pregnancy and up to randomization of this pregnancy (documented evidence of height and weight to calculate BMI is required)

Exclusion criteria

• Known history or presence of any clinically significant disease or condition which would be a contraindication to folic acid supplementation of up to 5 mg daily for the duration of pregnancy
• Known major fetal anomaly or fetal demise
• History of medical complications, including: renal disease with altered renal function, epilepsy, cancer, or use of folic acid antagonists such as valproic acid
• Individual who is currently enrolled or has participated in another clinical trial or who received an investigational drug within 3 months of the date of randomization (unless approved by the Trial Coordinating Centre)
• Known presence of: Alcohol abuse (≥ 2 drinks per day) or alcohol dependence, Illicit drug/substance use and/or dependence, Known hypersensitivity to folic acid, Multiple Pregnancy (triplets or more), Participation in this study in a previous pregnancy