Prenatal ultrasound diagnosis of congenital diaphragmatic hernia – associated malformations, chromosomal abnormalities and pregnancy outcome

Objective: To assess the current accuracy of routine prenatal ultrasound examinations in the detection and prevention of congenital diaphragmatic hernia (CDH) in different regions of Europe. Methods: Data from 19 European Congenital Malformation Registries within a 30- month-study period were included, analysing prenatal scans, the outcome of pregnancy and information on different screening policies for each country. Results: There were 173 cases of CHD among 690.123 pregnancies in the period monitored. The overall prenatal US detection rate was 57% with considerable variation in prenatal detection rates between regions. The mean gestational age at detection was 24.6 gestational weeks (11-38); 47% of CHD were diagnosed at ≥ 24 weeks of gestation. From 99 cases of CHD diagnosed prenatally, 33 were terminated. The proportion of TOPs for isolated CDH was significantly lower compared to TOPs performed in the syndromic, chromosomal and multiple malformation groups. Only 13 cases (8%) were stillbirths, but there was a high rate of neonatal deaths (32%). Conclusion: 57% of fetuses with CHD are identified by routine US screening in Europe with variations in detection between regions reflecting differences in policies, equipment and training. The rate of TOPs for CDH is relatively high, but mainly in cases of complex conditions. About 36% cases of CDH are associated with other conditions, therefore detailed and repeated ultrasound examination and karyotyping is recommended in prenatally diagnosed CDH. There is a need for repeated prenatal ultrasound screening in the third trimester of pregnancy because a large proportion of CDH is diagnosed after 24 weeks of gestation.