Factors adversely affecting lung growth.

Antenatal lung growth is adversely affected in conditions where there is intra-or extrathoracic compression, impaired fetal breathing movements and/or reduction in amniotic fluid volume. Postnatally, factors in infancy most commonly associated with abnormal lung function are passive smoking and premature delivery, its associated complications and management. Many conditions affecting lung growth are readily diagnosed by antenatal ultrasonography. Postnatally, pulmonary hypoplasia should be suspected if an infant requires high airway pressures during resuscitation and subsequent ventilatory support, in the absence of severe parenchymal disease on the chest radiograph. Antenatal therapy has been directed at relieving lung compression, but the efficacy of such interventions has not been proven in randomized trials. Certain disorders associated with impaired lung growth have a high perinatal mortality. Infants who are less severely affected suffer respiratory symptoms with lung function abnormalities or may only be distinguished by chronic tachypnoea during infancy.