Fetal Lung Hypoplasia Associated with Maternal Smoking: A Morphometric Analysis

Publisher Website
Google Scholar
Abstract
The recently reported animal (rat) model of maternal cigarette smoke exposure during pregnancy is characterized by fetal growth retardation and lung hypoplasia. The fetal lungs are further defined using quantitative histologic techniques. Compared to controls, lung volume at term is reduced in the experimental animals (0.28 vs. 0.33 ml, P < 0.005). Saccules (fetal alveoli) are reduced in number (3 .times. 106 vs. 5.5 .times. 106 P < 0.005) and increased in size (average saccular volume: 35 .times. 10-9 vs. 21 .times. 10-9 ml, P < 0.025). These changes in size and number are consequences of reduced formation of saccule partitions (septal crests) in the experimental lungs (volume density; 0.013 vs. 0.018, P < 0.025). Internal surface area is decreased in the hypoplastic lungs (161 vs. 198 cm2, P < 0.001). The total length of parenchymal elastic tissue is diminished (224 vs. 354 m, P < 0.05). The hypoplastic lungs contain fewer, larger saccules and the surface potentially available for gas exchange is reduced. Maternal smoking in rats adversely modifies fetal lung growth. If these observations are applicable to humans, then reduced lung growth in children of smoking mothers may begin antenatally.