Fetal cardiac function before labor predicts adverse perinatal outcome

OBJECTIVES: Current antepartum surveillance based on fetal biometry and cerebroplacental ratio (CPR) has limited ability to identify fetuses at risk of intrapartum compromise, as adverse outcomes may occur despite normal growth and Doppler findings. This study evaluated whether quantitative fetal cardiac geometry and myocardial deformation assessed before induction of labor can identify high-risk fetuses with normal CPR at increased risk of adverse perinatal outcome. METHODS: In this prospective observational study, 53 singleton high-risk pregnancies undergoing medically indicated induction of labor were included. All fetuses had normal admission cardiotocography and CPR. Before induction, fetal cardiac function was assessed using FetalHQ software from a subcostal four-chamber-view cine loop. Measurements included four-chamber-view circumference, global sphericity index, global longitudinal strain (GLS), and left- and right-ventricular free wall strain. The primary outcome was a composite adverse perinatal outcome (CAPO), including abnormal intrapartum cardiotocography requiring cesarean delivery, umbilical artery pH<7.10, base excess >10 mmol/L, or neonatal intensive care unit admission. RESULTS: CAPO occurred in 13/53 pregnancies (24.5 %). Compared with unaffected fetuses, those with CAPO showed reduced four-chamber-view circumference (100.4 [98.8-105.4] vs. 120.3 [110.8-133.0]; p=0.049), lower global sphericity index (1.15 [0.88-1.24] vs. 1.34 [1.24-1.37]; p=0.014), impaired GLS (p=0.001), and reduced left ventricular free wall strain (p=0.001). Right ventricular free wall strain showed a similar trend (p=0.085). CONCLUSIONS: Quantitative fetal cardiac assessment identifies high-risk fetuses with normal CPR who subsequently develop adverse perinatal outcomes. Fetal cardiac geometry and myocardial deformation may provide additional information on cardiovascular reserve and improve pre-induction risk stratification.