Nationwide Danish Register Based Study Showed a Stable Prevalence of Congenital Diaphragmatic Hernias From 1994 to...

Congenital diaphragmatic hernia (CDH) is a severe malformation with high morbidity and mortality. This Danish study evaluated the birth prevalence, co-occurring malformations, and temporal trends of CDH over nearly three decades.

Nationwide data from the Danish Biobank Register were used to identify liveborn infants diagnosed with CDH from 1994 to 2021. They were classified as non-syndromic or syndromic, based on co-occurring structural malformations or genetic or syndromic anomalies. Poisson regression was used to estimate the prevalence, including annual percentage changes.

We found that 272 of the 1 696 357 liveborn infants were diagnosed with CDH, with a stable prevalence of 1.60 per 10 000 live births (95% confidence interval 1.42-1.81). The majority (89.3%) had non-syndromic phenotypes: 79.4% of these had isolated CDH and 20.6% had CDH with co-occurring malformations, predominantly cardiac malformations. Syndromic CDH was observed in 29 (10.7%) infants, and its prevalence declined significantly over the study period (p < 0.03).

Although the prevalence of liveborn Danish CDH births remained stable, there was a shift towards fewer syndromic cases, possibly due to improved prenatal screening and increased terminations. The high proportion of major, co-occurring malformations emphasises the need for continued monitoring to address the healthcare needs of these patients.