Polymorphisms in endothelial nitric oxide synthase gene in early and late severe preeclampsia

•NO pathway seems to play a central role in uteroplacental changes during pregnancy.•Preeclampsia (PE) is associated with endothelial dysfunction.•Polymorphism in eNOS gene compromises NO bioavailability.•It has been admitted that early PE and late PE are different diseases.•Contradictory conclusions have been reported regarding eNOS gene polymorphisms and PE. Preeclampsia (PE) is characterized by hypertension and proteinuria, occurring after the 20th week of pregnancy in women who have had no previous symptoms. The disease progresses with generalized vasoconstriction and endothelial dysfunction. Clinically, it is important to diagnose the severe form of the disease (sPE), in which blood pressure and proteinuria are much higher. Recently, the gestational age (GA) of the onset of PE has led to the classification of this disease as early (GA