|| Checking for direct PDF access through Ovid
Of 10,122 singleton babies born from January 1, 1984 to March 31, 1988, we compared 1,154 term infants with high serum bilirubin levels (>12.9 mg/dl) to 1,154 infants with low serum bilirubin levels (<12.9 mg/dl) randomly selected from the remaining 8,968 subjects. We found that a high bilirubin level was significantly associated with male sex; maternal diabetes (chronic and gestational); pregnancy-induced hypertension; previous sibling with neonatal jaundice; delivery by cesarean section, vacuum, or forceps; epidural anesthesia; mother with blood type O; first delivery; cephalohematoma; short gestation; lower birth weight; and lower birth order (p < 0.01); and older maternal age, low percentile for birth weight, and the percentage of weight loss during hospitalization (p < 0.05). Variables with significantly different frequencies in control and study groups were used in a multivariate analysis, thus further refining the data by the use of logistic regression. Teenage mothers (<19 years old) had the lowest risk, whereas older mothers (>35 years old) had the highest risk of all age groups for having an infant with neonatal jaundice. First delivery and previous sibling with neonatal jaundice were also risk factors. Male sex, short gestation, and delivery by vacuum extraction were other notable risk factors. Our results suggest that, even among industrialized Western societies, risk factors may interact differently to produce higher neonatal serum bilirubin levels. The importance of a risk factor may also be dependent upon its relative prevalence in a parturient population.