Cardiac Changes in the Intrauterine Growth-Restricted Fetus

Intrauterine growth restriction (IUGR), which complicates approximately 3% to 10% of all pregnancies leads to preferential hemodynamic changes in affected fetuses. Advanced ultrasound modalities allow reliable and reproducible assessment of the intrauterine fetal cardiac function. Among other methods, combined cardiac output, individual ventricular ejection forces, E/A ratio, and Tei index can be utilized to quantify fetal heart function. While systolic ejection forces significantly increase with advancing gestational age in normal fetuses, there is a significant decline in the systolic function in IUGR fetuses. From the diastolic cardiac function point, IUGR fetuses have significantly lower left and right ventricular diastolic filling without significant changes in diastolic function. Overall, IUGR fetuses demonstrate progressive hemodynamic changes. It appears that there is an earlier and more pronounced right than left and diastolic than systolic fetal cardiac function deterioration in growth-restricted fetuses.

Keywords: fetal growth restriction, intrauterine fetal death, fetal circulation, systolic function