Role of the nitric oxide system related to fetal growth, mechanism of delivery, and peri-natal adaptation

S. PISANESCHI; A.M. SANCHEZ; S. BEGLIUOMINI; F.A.L. STRIGINI; P. GHIRRI; A. BOLDRINI; A.R. GENAZZANI; F. COCEANI; T. SIMONCINI

March 4-7, FIRENZE, ITALY.

Congreso; 14th World Congress of Gynecological Endocrinology, II Congresso ISGE Italia; 2010

INTERNATIONAL SOCIETY OF GYNECOLOGICAL ENDOCRINOLOGY (ISGE)

There is evidence that infants delivered by elective caesarean section have a higher occurrence of respiratory problem compared to vaginally born babies. The complex mechanisms that control the labor remains unrevealed. We investigated the role of the nitric oxide (NO) system related to intrauterine growth, gestational age at birth and mode of delivery, by combining the molecular analysis of umbilical vessels endothelial cells (HUVECs) and the umbilical levels of NO, asymmetric dimethylarginine (ADMA) and S-nitrosohemoglobin (S-NOHb). We analyzed newborns small for gestational age and with intrauterine growth restriction (IUGR), born at term and preterm by elective caesarean section with/out prolonged labor, with/out intra-partum hypoxia. The preterm delivery is related with a decreased NO release by HUVECs and an increased venous NO, associated with a lower concentration of S- NOHb. The umbilical vein NO and S-NOHb levels were significantly higher at birth in infants delivered vaginally or by caesarean section after labor as compared those of babies born through elective caesarean section. Umbilical NO levels were significantly higher in groups with intra-partum hypoxia versus controls, independently of centiles of growth. We propose that S-NOHb may be consumed under fetal hypoxic conditions in preterm babies, as a compensatory response to preterm respiratory distress. We speculate that the oxidative stress experienced during parturition may have a role in preserving the babies from respiratory problems, through the NO pathway.