Prenatal starvation, betamethasone and lung development in newborn rats.

This study examined the potential benefit of simultaneous transplacental betamethasone, which accelerates fetal lung maturation. Pregnant rats were placed in one of 4 groups: Control (C), fed ad libitum until term and given daily physiological saline injections from day 15 of gestation until term; Betamethasone (B), fed as group C but given daily physiological saline injections of 2.0 mg betamethasone/kg body weight from day 15 until term; Starved (S), given 50% rations from day 15 until term and injected as group C; Starved+Betamethasone (SB), fed as group S and injected as group B. Controls and group B did not differ in body or lung weight, protein or DNA, but group B lungs contained more lavageable and tissue surfactant. The S neonates weighed about 40% less than controls, with a proportional reduction in lung weight, DNA, protein or lavage and tissue phospholipids. Betamethasone may alleviate the impact of starvation on the developing lung by accelerating the process of alveolarization which was solved by caloric deprivation.