Feasibility and Accuracy of Early Fetal Echocardiography Performed at 13+0-13+6 Weeks in a Population with Low and High Body Mass Index: a Prospective Study.

PURPOSE The earlier the detection and diagnosis of congenital heart diseases (CHD), the greater the clinical benefit; however, early fetal cardiac examination can be a challenge. The aim of our study is to demonstrate that the fetal cardiac examination at 13+0-13+6 weeks can be as adequately assessed as the examination performed at 16 weeks in patients with low and high body mass index (BMI). METHODS The study was a prospective observational cohort study. One hundred pregnant women at low risk of congenital heart anomalies were divided into two groups: 49 women with low BMI (<25) and 51 women with high BMI (≥ 25). A complete fetal cardiac scan was performed on each patient at 13+0-13+6 weeks, via the transvaginal and transabdominal approaches, and at 16 weeks by the transabdominal approach. RESULTS The examination at 13+0-13+6 weeks was adequately assessed in at least one of the two routes in 97 patients, as opposed to 87 patients at 16 weeks. A significantly higher adequate assessment rate was obtained at 13+0-13+6 weeks than at 16 weeks (p=0.017). The transvaginal approach showed the best resolution of the three examinations in 42% of women with BMI ≥35. No CHD were overlooked. CONCLUSIONS Early fetal echocardiography is feasible and accurate at 13+0-13+6 weeks. Within patients with high BMI, early fetal echocardiography may be performed two weeks in advance, since it allows visualization of the fetal heart through the transvaginal route with a higher resolution in a large number of women, which is not feasible at 16 weeks.