The presence of meconium in the amniotic fluid was said to be a sign of "fetal distress" which may result in the birth of an asphyxiated infants. It was known that umbilical blood gas analysis was an objective index of fetal well-being.
Umbilical arterial and venous blood gas analyses were carried out in total 438 infants for the purpose of measuring the acidbase balance of infants at or near term from )regnancies complicated by meconium passage in utero and researching the difference n umbilical blood acidbase and gas status between the meconium and nonmeconium ,soup. About 2ml of umbilical cord blood was collected via doubly clamped cord mmediately after the delivery and before the first breath was taken. Cord blood collection was made by a syringe coated with 1000 unit heparin. Immediately after blood ollecction, umbilical blood acidbase and gas values were determined with the help c f Blood Gas Analyzer Stat Profile 5.
When the umbilical arterial. and venous blood gases were compared between the meconium and nonmeconium group, there was a significant difference in the mean pH values and bicarbonate concentration. There was a significant increase in the incidence of acidemia(defined as umbilical arterial pH less than 7.2), low 1minute and and 5n inutes Apgar score(<7) in newborns with meconium as compared with those with nonmeconium. The mean carbon dioxide tension of umbilical arterial and venous blood in neonates with thick meconium was significantly higher than those with thin meconium. The frequency of acidem.ia, low 1minute and 5minutes Apgar score(<7)in the flhick meconium group increased significantly than those in the thin meconium group. T sere was a greater incidence of meconium, Apgar score at 1minute or 5 minutes <7 ir, those neonates with umbilical arterial pH less than 7.2 than in those with higher pH values.
It was concluded that the acidbase and gas status of fetal blood was significantly altered when meconium, especially thick meconium is present in amniotic fluid.
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