The influence of pleural effusion on pulmonary growth in the human fetus.

The present study was performed to clarify the relation of cause and effect between pleural effusion and hypoplastic lung in the human fetus. In six cases with a duration of less than two weeks between the initial diagnosis of pleural effusion and delivery, lung weights were within the mean weight +/- 1.5 S.D. In fourteen cases with a duration of more than two weeks between diagnosis and delivery, seven cases had lungs with weights of less than -2.0 S.D. and twelve had lungs of less than -1.5 S.D. in weight. The incidence of lung weights less than -1.5 S.D. or -2.0 S.D. was significantly higher in cases with a diagnosis-delivery duration of more than two weeks, compared to those with a duration of less than two weeks. These results suggest that the development of hypoplastic lung in fetuses with pleural effusion may depend on the length of the presence of pleural effusion.