Assessment of total vascular resistance and total body water in normotensive women during the first trimester of pregnancy. A key for the prevention of preeclampsia

Introduction: Maternal cardiovascular system adapts to pregnancy, thanks to complex physiological mechanisms that involve cardiac output, total vascular resistance and water body distribution. Abnormalities of these adaptive mechanisms are connected with hypertensive disorders.

Objective: To identify patients at a high risk of developing hypertensive complications of pregnancy during the first trimester of pregnancy, through the use of non-invasive methods such as USCOM (Ultrasonic Cardiac Output Monitor) and Bioimpedance.

Materials and methods: We enrolled 120 healthy normotensive women during the first trimester of pregnancy obtaining all measurements with the USCOM system and Bioimpedance.

Results: 20 patients were excluded for a bad USCOM signal. The remaining patients (n = 100) were retrospectively divided into two groups: Group A (n = 75) TVR<1200 dynes s cm(-5), Group B (n = 25) TVR>1200 dynes s cm(-5). No statistically significant difference was identified in terms of water distribution, Fat Free Mass, Systolic/Diastolic Blood Pressure, Heart Rate, Hematocrit, Flow Time Corrected and Water Balance Index between the two groups. In contrast, higher values of the Cardiac Output, Stroke Volume, Fat Mass and Inotropy Index have been highlighted in the Group A. Moreover, in the Group A we found a better maternal-neonatal outcome and a lower incidence of hypertensive complications.

Conclusions: High TVR during the first weeks of gestation may be an early marker of cardiovascular maladaptation more than the evaluation of water distribution and, in particular, with respect to the single blood pressure assessment. Moreover lower values of Inotropy Index could be an indicative of the worst cardiac performance.