Objective To demonstrate the influence of the perinatal factors on neonatal serum bilirubin level in normal neonatal population. Methods Serum bilirubin level of 801 healthy babies were continuously monitored and the perinatal factors related to neonatal jaundice were recorded. 298 newborn with high serum bilirubin level(12. 9 mg/dl) were compared to 298 newborn with low serum bilirubin level randomly selected from the remaining 503 subjects. Results High bilirubin level was significantly associated with brease feeding, pregnancy induced hypertension of mothers, loss of birthweight, and high hematocrit( P0.001 ). There were no significant association of high bilirubin level with maternal age, maternal blood type, oxitocin induction of mothers, the length of the second labor stage, and the route of delivery. Conclusions Breast feeding, pregnancy induced hypertension of the mothers, high hematocrit, and loss of brithweight are important potential factors contributed to serum bilirubin level in early newborn stage.

OBJECTIVETo provide epidemiological data for revising the diagnostic criteria of neonatal hyperbilirubinemia in China.METHODSA survey was performed among full-term infants in multiple centers throughout the country. From less than 24 hours after birth, the infants' bilirubin levels were measured every day until the peak level fell to less than 68.4 mumol/L. Auditory brainstem responses were assessed in 56 infants randomly chosen from those with serum bilirubin levels of higher than 220.5 mumol/L.RESULTSJaundice in most infants was detected at 2-3 days after birth. The bilirubin level usually reached a peak level of 204 +/- 54.69 mumol/L at 5 days after birth and then fell. Among the 875 infants, the serum bilirubin levels in 34.4% of neonates were higher than 220.5 mumol/L. The mean serum bilirubin level of the infants during the first week after birth varied with geography (P < 0.001) and season (P < 0.001). The serum bilirubin level was significantly associated with gestation age (P < 0.01), delivery method (P < 0.01), weight loss (P < 0.001), and PCV elevation (P < 0.001) during the first three days after birth.CONCLUSIONSThe start time of neonatal jaundice was similar to that reported elsewhere, but the mean peak level in our study was higher than the reported. It is suggested that the diagnostic criteria for neonatal hyperbilirubinemia in China should be strict.