Maternal and fetal nitric oxide synthesis is decreased in pregnancies with small for gestational age infants

Our purpose was to evaluate whether maternal and fetal nitric oxidesynthesis in pregnancies with small for gestational age (SGA) infants aredifferent from those in pregnancies with appropriate for gestational age(AGA) infants. Maternal and fetal circulating nitrate and nitriteconcentrations were compared between 30 pregnancies with AGA and 10pregnancies with SGA at birth. End-products of nitric oxide synthesis weremeasured in maternal and cord venous blood samples using a fluorometricassay. Umbilical artery blood pH and PO2 were also measured. Maternalcirculating nitrite and nitrate concentrations (6.91 +/- 1.27 microM) inpregnancies with SGA were significantly lower than those (11.69 +/- 1.33microM) in pregnancies with AGA (P = 0.015). Fetal circulating nitrite andnitrate concentrations (7.54 +/- 1.09 microM) in pregnancies with SGA werealso significantly lower than those (11.24 +/- 1.08 microM) in pregnancieswith AGA (P = 0.024). There were no significant differences in umbilicalartery blood pH and PO2 between the two groups. These results suggest thatmaternal and fetal nitric oxide synthesis are decreased in pregnancies withSGA infants.