Objectives: Our objectives were to examine the relationship between umbilical venous pressure and cardiac size in nonimmune hydrops fetalis and to assess the role of cardiac failure in the pathogenesis of the disease.
Study design: Fourteen fetuses with nonimmune hydrops fetalis were investigated in a tertiary referral unit with high-resolution ultrasonography, echocardiography, and fetal blood sampling. Fetal heart size was assessed by measurement of the cardiothoracic ratio. Umbilical venous pressure was measured at the time of fetal blood sampling with a fluid-filled system.
Results: The 10 fetuses with elevated umbilical venous pressures had significantly increased cardiothoracic ratios (p = 0.02). These fetuses also had ascites. Four other fetuses had normal-sized hearts, normal umbilical venous pressures, and no ascites. There was a linear relationship between cardiothoracic ratio and umbilical venous pressure (r = 0.75, p = 0.003).
Conclusion: Measurement of umbilical venous pressure validates cardiothoracic ratio as a noninvasive assessment of cardiac function in nonimmune hydrops.