BIOELECTRICAL IMPEDANCE ANALYSIS AND HYPERTENSIVE DISORDERS OF PREGNANCY

Bioelectrical impedance analysis and hypertensive disorders of pregnancy Camilla Bulfoni Purpose Hypertensive disorders in pregnancy (HDP) are important causes of morbidity and mortality in pregnancy. Maternal cardiovascular system adapts to pregnancy, thanks to complex physiological mechanisms that involve cardiac output, total vascular resistance and water body distribution. In absence of an adaptation of the maternal cardiovascular systems pregnancy advances, there is an increased risk of fetal growth restriction and pregnancy induced hypertension. Bioelectrical impedance analysis (BIA) is a non invasive technique based on the body’s conduction of variable frequency to electrical current to determine total conductor volume of the body. Because water and electrolytes are the determinants of electrical conduction in the body, total body water (TWB) is easily evaluated. The aim of this study was to assess longitudinal change in body water compartments in pregnant woman and correlate to development of hypertensive disorders of pregnancy. Methods A total of 126 pregnant women were enrolled for this study. 118 women had a normal pregnancy (control group). The remaining 8 women development hypertension disorders during pregnancy (HDP group). Anthropometric measurements and BIA were performed during each trimester of pregnancy. Results Family history of hypertension, age, parity, % of smokers is not significantly different in HDP group compared with the control group. Body mass index, total of skinfold and waist circumference were higher in women who subsequently developed hypertension compared with controls in each trimester. TBW value in normal pregnancies showed a progressive increase throughout pregnancy. In HDP group, the increase of TBW is still significantly higher than control group. Performing ROC curve on the values of TBW were identified different cut-off for the early detection of HDP in different trimesters. In the first trimester TBW has a cut-off of 30.5 showing a sensitivity of 75% and a specificity of 52%. ( ROC area 0.66, p= 0.12) ; in the second trimester TBW has a cut-off of 34.4 showing a sensitivity of 100% and a specificity of 75% (ROC area 0.9, p=0.0008); better in the third trimester when TWB has a cut-off of 38,97 showing a sensitivity of 100% and a specificity of 92% ( ROC area 0.97, P=0.0001). Conclusions The evaluation of body composition by BIA is a practice absolutely non-invasive to the mother and the offspring and can be used for early identification of women at risk of developing hypertension.