The Relationship Between Growth and Perinatal Factors in Preterm Infants

Abstract

In the last few decades an increased survival of very preterm infants has been described, but concerns remain about their neurodevelopmental outcome and catch-up growth. Sub-optimal growth may be the result of a complex interaction of perinatal factors including inadequate nutrition. The more preterm the infant and the lower the birth weight, the higher the risk of poor growth, not only in the immediate postnatal period but also in the long term. Both intrauterine growth retardation and extrauterine growth restriction are associated with lower weight, shorter length, lower weight-for-length ratio, and smaller head circumference later in childhood. Very preterm infants who suffer from serious morbidities like sepsis, prolonged ventilator dependency, bronchopulmonary dysplasia, or necrotizing enterocolitis are at greater risk for postnatal growth restriction, as are infants who received postnatal corticosteroids. Aggressive nutritional support could help to prevent severe growth problems in the very preterm infants and is probably also related to a better neurodevelopmental outcome. However, this is where a dilemma exists for the neonatologist: according to recent research good catch-up growth in preterm infants possibly results in morbidities later in adulthood, like insulin resistance, increased blood pressure, and increased mortality from coronary artery disease later in life. Both bronchopulmonary dysplasia and the postnatal use of dexamethasone are important risk factors for poor growth later in childhood, irrespective of gestational age or birth weight. Severe intracranial ultrasound abnormalities like intraventricular hemorrhage grades 3 and 4, and cystic periventricular leukomalacia are also associated with poor growth later in childhood. This is true not only for head circumference but also for weight and length.