Multifrequency bioelectrical impedance analysis in women with a normal and hypertensive pregnancy.

BACKGROUND An increase in total body water is common in normal pregnancy. It is thought to be an important mechanism of maternal adaptation to pregnancy. OBJECTIVE The aim of the present study was to assess longitudinal changes in body water compartments in pregnant women and to correlate these measurements with the course of pregnancy. DESIGN One hundred seventy-three pregnant women with apparently normal, single pregnancies participated in this longitudinal study. Anthropometric measurements and multifrequency bioelectrical impedance were performed during the first, second, and third trimesters of pregnancy. RESULTS One hundred three of the women completed all of the measurements; 50 of the women had a normal pregnancy and 13 had gestational hypertension. Total body water, extracellular water, and intracellular water values in normal pregnancies showed a significant, progressive increase throughout pregnancy. In women with gestational hypertension, total body water, extracellular water, and intracellular water values showed an opposite trend, suggesting a lack of plasma volume expansion through fluid-retention mechanisms. CONCLUSIONS Our results show that multifrequency bioelectrical impedance analysis can be used to monitor variations in body water compartments in normal pregnancy and detect gestational hypertension.