The effect of gestational age on the incidence and duration of recurrent apnoea in newborn babies

ABSTRACT. Recurrent apnoea occurred in 249 (1%) of the 25,154 live born babies during the 6 year study period. Only 18 were born at term and in these a cause was usually apparent. The incidence of recurrent apnoea increased with decreasing gestational age and was maximal at 30–31 weeks gestation (54%) falling to 7% at 34–35 weeks. The incidence in those <30 weeks gestation was probably underestimated due to the high mortality rate in this group in the earlier years of the study. With increased survival in 1978–79, the majority of survivors at those gestations developed apnoea. Apnoea usually commenced in the first 2 days of life (77%) and was unlikely to commence after 7 days. The lower the gestational age at birth the longer the apnoea continued; it usually ceased by full term. The predominant effect of gestational age on the incidence and duration of recurrent apnoea suggests that immaturity plays a major causative role. Perinatal insults which are more common in those of lowest gestation may contribute to its incidence and severity.