Maternal hemodynamic adjustments in idiopathic fetal growth retardation.

The hemodynamic characteristics of 11 normotensive gravidas with idiopathic fetal growth retardation (FGR), were compared with 11 controls of similar age, parity and body size. At weeks 36-38 of gestation, plasma volume was 3,161 +/- 121 ml in controls and 2,624 +/- 95 ml in the FGR group (p < 0.003); cardiac output (CO) was 6,191 +/- 132 ml/min in controls and 5,483 +/- 186 ml/min in the FGR group (p < 0.01). Total peripheral vascular resistance (TPVR) was lower in controls than in FGR (1,031 +/- 33 vs. 1,306 +/- 62 dyn/s/cm5; p < 0.001). Birth weight was correlated with both plasma volume (r = 0.61; p < 0.01) and CO (r = 0.53; p < 0.02) and inversely correlated with TPVR (r = -0.69; p < 0.001). These results are in line with the hypothesis that a reduced plasma volume leads to a lower CO and, secondarily, to reduced uterine blood flow and FGR.