The clustering of disorders in infants born before the 28th week of gestation

Abstract

Aim: To see whether disorders prevalent in infants born extremely preterm cluster.

Design: Observational cohort study.

Setting: University-affiliated newborn intensive care nurseries.

Subjects: One thousand two hundred and twenty-three infants born before the 28th week of gestation who survived until 36 weeks postmenstrual age when the diagnosis of bronchopulmonary dysplasia (BPD) could be made.

Interventions: None.

Main outcome measures: Cerebral white matter damage (an echolucent lesion, or moderate or severe ventriculomegaly on a protocol cranial ultrasound scan), BPD, retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC) and early and late bacteremia.

Results: After adjustment for gestational age, children who had severe NEC (Bell stage IIIb) were at increased risk of cerebral white matter damage, severe ROP (stage 3+), and severe BPD (defined as both oxygen and ventilator dependent). Children who had early bacteremia were at increased risk of late bacteremia and severe ROP. Those who had severe ROP were at increased risk of severe BPD and both early and late bacteremia.

Conclusions: Necrotizing enterocolitis is the disorder common to most of the clusters, but we do not know if its onset occurred before the others. Organ-damage-promoting substances, however, have been found in the circulation of newborn animals with bowel inflammation, supporting the view that NEC contributes to the damage of other organs.

Figure 1. The clustering of disorders in infants born before the 28th week of gestation

Two models of the interrelationships among the disorders that occur preferentially among infants born at extremely low gestational ages. The first model (A) assumes that a common characteristic or exposure contributes to each of the four groups of disorders. The second model (B) assumes that NEC produces conditions that promote the occurrence of the other disorders.