The implementation of a nationwide anomaly screening programme improves prenatal detection of major cardiac defects: an 11-year national population-based cohort study

Objective: To evaluate whether a nationwide prenatal anomaly screening programme improves detection rates of univentricular heart (UVH) and transposition of great arteries (TGA), and whether maternal risk factors for severe fetal heart disease affect prenatal detection. Design: Population-based cohort study. Setting: Nationwide data from Finnish registries 2004–14. Population: A total of 642 456 parturients and 3449 terminated pregnancies due to severe fetal anomaly. Methods: Prenatal detection rates were calculated in three time periods (prescreening, transition and screening phase). The effect of maternal risk factors (obesity, in vitro fertilisation, pregestational diabetes and smoking) was evaluated. Main outcome measures: Change in detection rates and impact of maternal risk factors on screening programme efficacy. Results: In total, 483 cases of UVH and 184 of TGA were detected. The prenatal detection rate of UVH increased from 50.4% to 82.8% and of TGA from 12.3% to 41.0% (P < 0.0001). Maternal risk factors did not affect prenatal detection rate, but detection rate differed substantially by region. Conclusions: A nationwide screening programme improved overall UVH and TGA detection rates, but regional differences were observed. Obesity or other maternal risk factors did not affect the screening programme efficacy. The establishment of structured guidelines and recommendations is essential when implementing the screening programme. In addition, a prospective screening register is highly recommended to ensure high quality of screening. Tweetable abstract: Implementation of a nationwide prenatal anomaly screening improved detection rates of UVH and TGA.