| Abstract: | Unconjugated estriol (E3) was quantified in serum of umbilical cord blood of 533 newborn infants, 360 of whom were delivered between 23 and 37 wk of gestation. Serum E3 levels rose (F = 7.71, p less than 0.0001) as a function of gestational age; the mean concentration of E3 at 37.5-42 wk of gestation (105 ng/ml, n = 173) was significantly higher than that in serum of newborns delivered at 23-28 wk of gestation (63 ng/ml, n = 33). Umbilical cord serum levels of E3 were significantly higher among newborns delivered vaginally between 31.5 and 42 wk of gestation than among newborns delivered by cesarean section (p less than 0.005). Although serum E3 levels correlated highly (p less than 0.0001) to newborn weight throughout the entire period of gestation, there was no relationship of newborn weight to umbilical serum E3 levels within a given gestational period. Also, the umbilical serum levels of E3 in male infants were similar to those of female infants at each gestational age. Significant changes in umbilical serum levels of E3 as a function of gestational age were not observed among newborns (n = 90) who developed respiratory distress syndrome (RDS). The mean umbilical serum concentration of E3 in newborns delivered at 34.5-37 wk of gestation who developed RDS were significantly lower (p less than 0.01) than that in similar aged newborns whose lung function was normal.(ABSTRACT TRUNCATED AT 250 WORDS) |
