Incidence of congenital thoracic malformations detected by prenatal ultrasound.

Background The increased and earlier use of prenatal ultrasound has facilitated the detection of congenital thoracic malformations (CTMs). Our Pediatric Pulmonology Institute follows an increasing number of patients with CTMs. Thus, we aimed to evaluate and describe prenatal sonographic findings of CTM, and to estimate changes in detection rates of CTMs over a period of 16 years. Methods A retrospective, cross-section analysis of prenatal ultrasound (US) screening tests carried out in a large community-based clinic, comparing two periods: 2001-2007 and 2007-2017. Results A total of 34 716 prenatal US were performed at a median gestational age of 15.4 weeks (range, 11.6-23.9) and 15.7 weeks (range, 12-33.6) in 2001-2007 and 2007-2017, respectively. In 2001-2007, 12 016 prenatal US tests detected 19 CTMs, compared to 30 CTMs in 22 700 tests in 2007-2017. Detection rates did not change (1.58/1,000 in 2001-2007 versus 1.32/1,000 in 2007-2017, P = 0.64). The most common abnormality was congenital pleural effusion (CPE) (17 cases, 34.7%), followed by congenital pulmonary airway malformation) and congenital diaphragmatic hernia; 13 cases each, 26.5%. Twenty CTMs, mainly congenital diaphragmatic hernia and CPE, were associated with other fetal lesions. Conclusions Congenital diaphragmatic hernia and CPE tend to appear with multiple lesions and warrant further attention. The incidence rates stayed stable when comparing the last decade to previous years. Thus, the increased referral of CTM can be attributed to an increase in the number of prenatal screening studies performed, rather than a true higher incidence.