Sensitivity and specificity of second trimester anatomy ultrasound in the detection of cardiac anomalies in fetal echocardiogram in twin pregnancies

To determine the sensitivity and specificity of twin detailed second trimester anatomy ultrasound in the prediction of abnormal fetal echocardiogram (FE) when both were performed by Maternal-Fetal Medicine (MFM) specialists. Retrospective cohort study of all patients with a twin gestation from 2020-2022 who had a detailed second trimester anatomy ultrasound and FE performed by a group of US specialists in MFM working at a tertiary-level urban academic centre with AIUM accreditation. FE was performed as indicated by AIUM and ISUOG guidelines. We calculated the sensitivity and specificity of a detailed anatomy ultrasound to detect anomalies diagnosed with FE. 344 fetuses had a detailed twin second trimester anatomy ultrasound and FE performed by MFM, of which 70 (20.3%) had persistently suboptimal cardiac views and were excluded. Of the remaining fetuses, 266 (97.1%) did not have cardiac abnormalities noted on either scan. Two fetuses were diagnosed as normal on anatomy ultrasound with subsequent minor anomalies of ventricular septal defects (VSD) diagnosed on FE, with a 33.3% false-negative rate. Two fetuses had suspected cardiac abnormalities on anatomy ultrasound, but were found to be normal on subsequent FE, with a false-positive rate of 0.7%. In twin pregnancies, detailed second trimester anatomy ultrasound had a sensitivity of 66.72% and specificity of 99.3% at detecting cardiac anomalies on FE. We found high specificity of twin detailed anatomy ultrasound to rule out cardiac anomalies. There were two cases of undiagnosed VSDs on second trimester anatomy ultrasound later diagnosed on FE. There were no major cardiac anomalies that were missed. Overall, twin gestation does not decrease the quality of the anatomy ultrasound which has high specificity. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.