Umbilical venous pressure and Doppler flow pattern of inferior vena cava in the fetus.

Umbilical venous blood pressure (UVP) was measured at fetal blood sampling using cordocentesis in 113 fetuses. Among these, both inferior vena cava (IVC) Doppler flow pattern, when the preload index was set as a parameter of reversed flow, and UVP were measured in 50 fetuses. We evaluated whether direct measurement of UVP, representing fetal central venous pressure, could be replaced by an assessment of reversed IVC blood flow. Normal mean UVP was 4.89 +/- 3.22 mm Hg, whereas no correlation was observed between UVP and gestational week. When the extent of reversed blood flow from the right atrium to the IVC was expressed as a preload index (PLI), there was a significant correlation between the index and UVP (r = 0.463; P < 0.001). When the abnormal range of PLI was set at 0.45, the sensitivity of an estimate of abnormal UVP (more than 1.5 SD plus the mean) was 0.54 and the specificity was 0.89. Measurement of UVP is necessary for the prediction of fetal cardiac function. PLI can be substituted for the UVP measurement. However, PLI should be supplemented with other parameters for an accurate fetal cardiac function evaluation.