Influence of the central nervous system on fetal lung development. Experimental study.

Upper cervical cord injury was produced in fetal rabbits at 22-26 days' gestation. In 11 setuses with severe cord injury delivered at 28-29 days' gestation there was a median reduction in lung weight (expressed as a proportion of body weight) of 43% and a median reduction in estimated total lung DNA of 16% in comparison with paired operated littermates with intact cords. The hypoplastic lungs showed collapse on histology; if cord damage had been inflicted before 24 days' gestation there was retarded maturation. We conclude that the central nervous system plays a vital role in fetal lung growth and maturation, probably by maintenance of fetal respiratory movements.