Total body water estimation and maternal cardiac systolic function assessment in normal and gestational hypertensive pregnant women.

Background: The importance of establishing correlations between cardiac function (cardiac output and stroke volume) and total body water (TBW) content in normal and hypertensive pregnancy focuses primarily on their potential relevance in treatment. Total body water content and cardiac function were evaluated in 25 normotensive (N) and 22 gestational hypertensive (GH) pregnant women matched for age, gestational age, and pre-pregnancy body mass index (BMI) during the third trimester of gestation.

Material/methods: Patients underwent maternal echocardiography, bioelectrical impedance analysis (BIA), and hematocrit (Hct) evaluation, and the water balance index (WBI), i.e. the ratio of total body water to hematocrit, was computed. Hematocrit showed significantly lower values in normal than in GH women (31.9+/-2.2% vs. 36.2+/-2.5%; p<0.001).

Results: There was no difference in TBW between the two groups. The WBI was higher in normal than in GH women (1.35+/-0.20 l.kg-1.m-2 vs. 1.19+/-0.18 l.kg-1.m-2; p<0.001). Normal subjects showed a higher stroke volume than GH patients (78.0+/-9.7 ml vs 67.9+/-10.2 ml; p=0.001). Atrial function was also higher in normal than in GH women (left atrial fractional area change: 57.4+/-5.1% vs. 42.5+/-7.5%; p<0.001). Correlation was found between stroke volume and WBI (r=0.93, p<0.0001).

Conclusions: Maternal cardiac function and the water balance index are strongly related and might help in comprehending the mechanisms of adaptation in physiologic and hypertensive pregnancy.