To the Editor: We read with great interest the letter of Professor Saigal. She pointed to the shortcomings of our study (1). We fully agree that the design of the study was not perfect. Still, our study suggested that term infants with moderate hyperbilirubinemia (233–444 μmol/l) more often showed minor neurological dysfunction (MND) during the first year of life than non-jaundiced matched controls. The differences in neurological outcome between the groups persisted in multivariate analyses where factors such as birthweight, gestational age at birth, gender, mode of delivery, and social class were taken into account. Moreover, within the jaundiced group a dose-response relationship was found: at the age of 12 months the severity of MND was related to the degree of neonatal hyperbilirubinemia. The degree of hyperbilirubinemia, which was related to the duration of hyperbilirubinemia and to treatment with phototherapy, explained neurological outcome at 12 months better than the duration of hyperbilirubinemia or phototherapy.

The Editorial and the Comments, which accompanied the publication of our study, reflect that the subject of the treatment of moderate degrees of hyperbilirubinemia in term infants is far from settled. We are talking about a large group of infants. How can they be managed best? Do they really run an increased risk of MND throughout childhood? Is a potentially increased risk related to a specific degree of hyperbilirubinemia? In other words, can we determine a safety level, i.e. a bilirubin-level below which the risk for neurological morbidity is not increased? In case moderate degrees of hyperbilirubinemia really are related to an increase in neurological morbidity, can this prevented by specific treatment such as phototherapy? Adverse neurological sequelae of phototherapy, in contrast to short-term beneficial ones (2), never have been reported. The study of Paludetto et al. (3), mentioned by professor Saigal, does not allow for the conclusion that phototherapy negatively affects the neonate's neurological condition. Paludetto et al. concluded that the poorer neurological performance of the jaundiced infants (n = 12) at 1 month could be the result of the jaundice itself or the phototherapy.

In order to be able to answer the critical questions raised, further research on the effect and management of moderate degrees of hyperbilirubinemia in full-term infants is urgently needed.