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Objective. In this study, we investigated prospectively the incidence of significant hyperbilirubinemia and demographic and laboratory characteristics and pattern of serum bilirubin levels of near-term newborns (35–37 weeks’ [245–265 days’] gestation) by comparing them with those of term newborns (38–42 weeks’ [266–294 days’] gestation) longitudinally in the first 7 days of life; we also aimed to determine the value of an early (6th-hour) serum bilirubin measurement in predicting the development of significant hyperbilirubinemia later during the first week of life in near-term newborns.Methods. Serum total bilirubin measurements were initially made at the 6th hour of life and repeated daily for the next 4 days, and a last measurement was performed on the 7th day (150th hour) in 219 term newborns (term group) and 146 near-term newborns (near-term group). Newborns with serum total bilirubin levels of ≥8 and ≥12 mg/dL on day 2, ≥12 and ≥15 mg/dL on day 3, and ≥14 and ≥17 mg/dL on days 4, 5, and 7 for birth weights 2000 to 2500 g and >2500 g, respectively, were defined to have significant hyperbilirubinemia, and phototherapy treatment was started. The predictive ability of the 6th-hour serum total bilirubin value in determining the development of significant hyperbilirubinemia in the near-term group was assessed on the basis of the placement of any of the first week’s serum bilirubin measurements in the ≥95th percentile of the study population. A Gaussian distribution curve, the 5th, 30th, 60th, and 95th percentiles, and 4 percentile tracks were obtained from mean serum total bilirubin values. On the basis of the percentile tracks with various sensitivity, specificity, and negative and positive predictive values, a nomogram demonstrating the 4 percentile tracks as risk-zone demarcators with divided risk zones was produced.Results. Twenty-three newborns (10.5%) in the term group and 37 newborns (25.3%) in the near-term group had significant hyperbilirubinemia and required phototherapy. When the daily mean serum bilirubin levels of the 2 groups were compared, the first 4 days’ values did not significantly differ between the 2 groups, whereas the 5th and 7th days’ values were significantly higher in the near-term group. There were significant differences between the 2 groups with respect to the incidence of significant hyperbilirubinemia, hematocrit, Apgar score, and mode of delivery. On the age-specific nomogram, the zone >95th percentile was labeled as high risk, and that Conclusions. Near-term newborns should not be treated as term newborns in the approach to management of hyperbilirubinemia, because infants of 35 to 37 weeks’ gestation had significantly lower birth weights, significantly higher serum total bilirubin levels on days 5 and 7, and were 2.4 times more likely to develop significant hyperbilirubinemia than those of 38 to 42 weeks’ gestation in the present study. In near-term newborns of 35 to 37 weeks’ (245 to 265 days’) gestation, the decision to diagnose and treat significant hyperbilirubinemia should be made on the basis of risk status (percentile distribution of the serum bilirubin values on postnatal age) rather than using birth-weight-based thresholds. A nomogram constructed from daily serum bilirubin values of each population, as we present herein, can be used in assessing the age (hour)-specific jaundice risk (high, intermediate, or low) of each near-term newborn.

Objective. In the era of early discharge of newborns from the hospital, newborns with ABO incompatibility are at especially greater risk for developing a subsequent significant hyperbilirubinemia because some of these infants also may present with some degree of ABO isoimmune disease. In this study, we aimed to determine prospectively the critical serum total bilirubin level to predict significant hyperbilirubinemia and severe hemolytic disease in healthy term newborns with ABO incompatibility based on a serum bilirubin measurement made at a postnatal age at which all newborns are at the hospital before discharge and at which any therapeutic intervention, if necessary, could be started as early as possible.Methods. A total of 136 healthy term newborns with ABO (O-A or O-B) blood group incompatibility were followed prospectively with daily serum total bilirubin measurements for the first 5 days of life. Newborns with serum total bilirubin levels of ≥5 mg/dL and an increase in serum total bilirubin concentration of >0.5 mg/dL/h in the first 24 hours, ≥12 mg/dL on day 2, ≥15 mg/dL on day 3, and ≥17 mg/dL on days 4 and 5 were defined to have significant hyperbilirubinemia and were started on phototherapy treatment. Additional treatment modalities, including intense phototherapy, intravenous immunoglobulin treatment, and exchange transfusion, were used when serum bilirubin concentrations exceeded 20 mg/dL or increased by >1 mg/dL/h despite a phototherapy treatment of at least 4 hours. The additional assessment of the predictive ability of the sixth-hour serum total bilirubin value in determining the development of significant hyperbilirubinemia was made on the basis of the placement of any of the first 5 days’ serum bilirubin measurements in the ≥90th percentile of the study population. On the basis of the percentile tracks constructed from the 10th, 35th, 50th, 60th, and 90th percentiles of serum total bilirubin values, a nomogram demonstrating the 3 percentile tracks as risk zone demarcators with divided risk zones was produced.Results. Twenty-nine newborns (21.3%) had significant hyperbilirubinemia. There were significant differences between the newborns who did and the newborns who did not develop significant hyperbilirubinemia with respect to the reticulocyte count (4.39 ± 3.46% vs 2.95 ± 1.63) and the presence of a direct antiglobulin test positivity (6 of 23 vs 0 of 107) and a sibling with neonatal jaundice (6 of 23 vs 5 of 102). A mean serum bilirubin level of ≥4 mg/dL at the sixth hour of life was determined to have the highest sensitivity (86.2%) and negative predictive value (94.5%) and a positive predictive value of 39.7% to predict the newborns who would develop significant hyperbilirubinemia. At the mean serum bilirubin level of 6 mg/dL, the sensitivity, specificity, and negative and positive predictive values were 100%, 91.5%, 100%, and 35.3%, respectively, in diagnosing 6 cases of severe ABO hemolytic disease. On the hour (age)-specific percentile-based nomogram, the zone above the 90th percentile was determined as high risk and that below the 35th percentile as low risk.Conclusions. The reticulocyte count, a positive direct antiglobulin test, and the presence of a sibling with neonatal jaundice were determined to be the good predictors for the development of significant hyperbilirubinemia and severe hemolytic disease of the newborn. A serum bilirubin measurement and the use of the critical bilirubin levels of 4 mg/dL and 6 mg/dL at the sixth hour of life will predict nearly all newborns who will have significant hyperbilirubinemia and those who will develop severe hemolytic disease of the newborn, respectively. An hour (age)-specific percentile-based nomogram can be used to predict which newborn is at high risk (≥90th percentile), intermediate risk (35th–90th percentiles), and low risk (

Objective.The recognition, follow-up, and early treatment of neonatal jaundice has become more difficult, since the earlier discharge of newborns from hospitals has become common practice. This prospective study was undertaken to identify the newborns at risk for developing significant hyperbilirubinemia later during the first days of life by measuring the serum bilirubin levels of the first 5 days of life to determine the critical predictive serum bilirubin value on the first day of life.Methodology.A total of 498 healthy term newborns were followed with daily serum total bilirubin measurements for the first 5 days of life, and cases with serum bilirubin levels of ≥17 mg/dL after 24 hours of life were defined to have significant hyperbilirubinemia.Results.No newborns had a serum total bilirubin level of ≥17 mg/dL in the first 72 hours of life. Sixty of 498 cases (12.05%) had significant hyperbilirubinemia after 72 hours of life, and these cases had significantly higher bilirubin levels than those who did not develop significant hyperbilirubinemia on each of the first 5 days' measurements. Of the 206 newborns who had a serum bilirubin level of ≥6 mg/dL in the first 24 hours, 54 (26.21%) developed significant hyperbilirubinemia, whereas only 6 of the 292 newborns (2.05%) who had a serum bilirubin level of 20 mg/dL, requiring a phototherapy treatment later during the first days of life.Conclusions.A serum bilirubin measurement and the use of the critical bilirubin level of 6 mg/dL in the first 24 hours of life will predict nearly all of the term newborns who will have significant hyperbilirubinemia and will determine all those who will require a phototherapy treatment later during the first days of life.