MTHFR and fetal growth restriction: Patients with plasminogen activator inhibitor 1 (PAI-1) and methylenetetrahydrofolate reductase (MTHFR) had significantly higher odds for IUGR of unknown cause (P < .001 and P = .002, respectively) with OR 13.546 (CI 95% 3.79–48.37) and 8.139 (CI 95% 2.20–30.10), respectively.