Effect of Delayed Cord Clamping on Chronic Intermittent Hypoxia in Extremely Premature Infants

Preterm birth is a major health care concern and although survival of premature infants has improved, neonatal morbidities persist especially in cases of extreme prematurity. Apnea of prematurity, mainly due to immature respiratory control, is a major complication in Neonatal Intensive Care Units (NICU) occurring in virtually all infants born before 28 weeks gestation. Chronic Intermittent Hypoxia (CIH) is generally attributed to immature respiratory control resulting in apnea and respiratory pauses, often superimposed upon suboptimal lung function. Although short respiratory pauses may seem clinically insignificant with minimal consequence, when resulting in CIH lead to both short-term and long-term morbidities. Recent studies have shown that higher incidence of intermittent hypoxic events in preterm infants is associated with severe retinopathy of prematurity requiring laser therapy. In addition, multiple human and animal studies have shown that CIH results in cardiorespiratory instability, sleep disordered breathing, altered growth, decreased neuronal integrity and neurodevelopmental impairment. Although there is growing evidence that CIH in preterm infants is an important medical problem, the mechanisms involved are not entirely explained and optimal treatment strategies have not been determined, especially for the extremely premature infant (e.g. those