Background:The aim of this work was to investigate in a prospective study whether moderate hyperbilirubinemia in healthy term neonates is associated with an increase of minor neurological dysfunction (MND) and behavioral problems up to 18 mo. Methods: We enrolled 43 healthy term infants with a bilirubin level ≥220 µmol/l (BILI group) at 72-96 h postnatally at the University Medical Center Groningen (UMCG), including eight referrals for hyperbilirubinemia. Seventy healthy term infants born at the UMCG with bilirubin level <220 µmol/l served as comparisons (COMP group). We evaluated the neurologic condition neonatally and at 3 and 18 mo; behavior was evaluated at birth and 18 mo. results: Rates of MND in BILI and COMP groups were similar at all ages. However, bilirubin levels of ≥300 µmol/l (n = 10) were associated with an increased risk of complex MND (odds ratio: 4.21; 95% confidence interval: 1.02-17.37). Neonatally, BILI infants were more often lethargic than COMP infants (odds ratio: 3.54; 95% confidence interval: 1.32-9.51); at 18 mo, they had higher hyperactivity scores (effect: 0.32; 95% confidence interval: 0.08-0.56). conclusion: Occurrence of complex MND at 18 mo in infants with moderate hyperbilirubinemia was not different from that in comparison infants, but bilirubin level ≥300 was associated with an increased risk of complex MND. This study also suggests that minor behavioral effects of moderate hyperbilirubinemia cannot be excluded.h yperbilirubinemia in newborn infants is treated according to an algorithm in which neonates >35 wk of gestational age without jaundice or without risk factors for the development of severe hyperbilirubinemia are considered as having low risk for hyperbilirubinemia and they may be discharged >72 h after birth. When postnatal age is <72 h or if risk factors are present, discharge is allowed if follow-up ensured. Otherwise, a predischarge total serum bilirubin or transcutaneous bilirubin measurement should be performed. Subsequently, the bilirubin level is plotted in an hour-specific nomogram according to the infant's age in hours. Treatment will be started if the infants fulfill the criteria for treatment.For instance, at 72 h, phototherapy is started in the lower-risk group (≥38 wk and well) at 300 μmol/l. In the Netherlands, an adapted version, which takes into account the relatively large number of home deliveries, was developed in 2009 (1). The Dutch adaptation does not include an obligatory observational period in the hospital and age at discharge but takes two structured clinical evaluations during the first 4 d as a starting point. In case of suspicion of hyperbilirubinemia, total serum bilirubin/transcutaneous bilirubin is measured (1).We previously reported in a small group of term babies a strong dose-response relationship between the degree of hyperbilirubinemia and the severity of minor neurological dysfunction (MND) at 12 mo. The data suggested that in healthy term neonates, bilirubin levels should not exceed 335 μmol/l (2). The primary aim of the current st...