Diaphragmatic hernia in the south-west of England.

A retrospective anatomical, family, and epidemiological study was made of 143 patients (81 female and 62 male) with diaphragmatic hernia who were born in the south-west of England between 1943 and 1974. Thirty-nine cases were stillborn. Seventy-five per cent of patients had a left-sided diaphragmatic defect, 22% had a right-sided defect, and 3% had a bilateral defect. Fifty per cent of the patients had other congenital malformations, most frequently of the nervous system. No maternal age or birth order effect was noted. Cases of diaphragmatic hernia without other malformations had in general a normal fetal growth rate. Eight per cent of the cases were illegitimate. There were two pairs of twins discordant for diaphragmatic hernia, one pair being dizygotic and the other monozygotic. In no case of diaphragmatic hernia was there a relative affected with a diaphragmatic hernia. The most common type of diaphragmatic defect was a posterolateral hernia (92%), followed in frequency by an eventration of the diaphragm (5%), the least common defect being a retrocostosternal hernia (2%). Diaphragmatic hernia appears to be aetiologically as well as anatomically heterogeneous. In this series there were two cases of trisomy 18, one case of trisomy 21, one case trisomic for a small part of chromosome 20, and two cases with the Pierre Robin syndrome. It seems likely that diaphragmatic hernia is a non-specific consequence of several teratological processes.