MTHFR and Rare hereditary thrombophilia: In this direction, a case-control study by Dugalić et al. [35] containing 33 pregnant patients with IUGR of unknown cause tested for thrombophilia and 66 controls, and found a statistically significant link between IUGR and plasminogen activator inhibitor 1 (PAI-1) and MTHFR C677T homozygote mutation, with an OR 13.546 (CI 95% 3.79–48.37), p < 0.001, OR 8.139 (CI 95% 2.20–30.10), p = 0.002, respectively.