Factors influencing jaundice in immigrant Greek infants.

A study of 887 consecutively born immigrant Greek and 220 Anglo-Saxon Australian infants has shown that serum bilirubin concentrations are influenced by these factors: breast feeding, delivery with forceps, gestation, birthweight, sex of the infant, presence of hypoxia, presence of blood group incompatibility, a positive direct Coombs's test, maternal sepis, and administration to the mother of promethazine hydrochloride, reserpine, chloral hydrate, barbiturates, narcotic agents, diazepam, oxytocin, aspirin, and phenytoin sodium. Apart from the administration of promethazine hydrochloride, reserpine, chloral hydrate, and quinalbarbitone sodium, only two factors, breast feeding and delivery by forceps, occured with different frequencies in the immigrant Greek and the Australian infants. Among the Greek infants with jaundice, there were few where the cause of the jaundice was inapparent. The immigrant Greek and Australian newborn populations were therefore remarkably similar. Since differences of frequency and severity of jaundice do exist in infants born in Greece, this difference must be lost when the parents emigrate, and therefore an environmental factor must be incriminated as the causative agent for jaundice of unknown origin in Greece.