NOS3 and newborn respiratory distress syndrome: One possible mechanism by which the GG genotype and G allele of NOS3 could influence the risk of RDS in very preterm and very low birth weight infants in the present study could be through the generation of low levels of FeNO, which could mitigate lung inflammation and interfere with pulmonary vascular remodelling, thus determination of FeNO or plasma levels of NO metabolites is worthy for further study.