Learning curve and factors influencing the feasibility of performing fetal echocardiography at the time of the first-trimester scan.

The purpose of this study was to assess the learning curve and factors influencing the feasibility of performing a complete fetal cardiac examination at the time of the first-trimester scan. The study included 103 fetuses undergoing first-trimester scans. The maternal body mass index, fetal crown-rump length, and 8 cardiac parameters were evaluated: 4-chamber view, tricuspid regurgitation, outflow tract crossover, bifurcating pulmonary artery, 3-vessel view, aortic arch, superior and inferior venae cavae on sagittal views, and Doppler images of the ductus venosus. All examinations were performed transabdominally by a single sonologist. The average times from the first to last cardiac images obtained were calculated. A complete examination was feasible in 55% of the cases: 15% of the first 52 and 94% of the last 51. Of the 8 cardiac parameters, 59.5% were seen in cases 1 to 21, 75.0% in cases 22 to 52, and 98.6% in the last 51 cases (P = .0001). The average times spent on the examinations increased from 4.37 to 9.3 minutes among the 3 groups (P = .032). There was no statistically significant influence for the crown-rump length (P = .899) or body mass index (P = .752). This study indicates that a fetal cardiac examination is feasible in the first trimester. Sonographer experience and the examination duration seem to be the most influential factors affecting the completeness of the examination.