GSTM1 and hypertensive disorder: The differences in demographic and clinical characteristics were either not significant (maternal age, maternal education, parity, and number of antenatal care visits, hypertensive disease/severe pre-eclampsia/eclampsia, body mass index (BMI) ≥ 25 kg/m2, hemoglobin (Hb) < 8 g/dl, multiple birth, preterm birth and term birth) or observed difference was very small and may not be clinically significant (antepartum hemorrhage; 1.5% vs. 1.4%) [18, 19].