Bioelectrical Impedance Vector Analysis (BIVA) for the monitoring of body composition in pregnancy

Abstract

Background/Objectives: during pregnancy, body composition alterations can be considered as markers of complications and in this context, a non-invasive and low-cost method such as Bioelectrical Impedance Vector Analysis (BIVA), can be employed to monitor such changes. This study aimed at identifying body compartments trend during physiological pregnancy. Subjects/Methods: classic and specific BIVA variables have been measured in a sample of 37 pregnant women approximately every 4 weeks of gestation and once postpartum. Researchers used both longitudinal and cross-sectional approach. The first case included data of women from the 11 th to the 15 th week along with data from the 28 th to the 32 nd week of gestation. The cross-sectional approach regarded two more specific moments ( 11th -12 th weeks and 30 th -31 st weeks) and data within two months postpartum. Results: the longitudinal approach showed a significant decrease in classic BIVA variables (R/H, Xc/H, Z/H p<0.001) and a shortening of the vector, pointing out that TBW and hydration increased significantly. Specific vector length increased significantly, indicating a physiological gain of FM% (p<0.01). The cross-sectional approach showed lower values of R/H, Xc/H, Z/H between 12 th -13 th and 30 th -31 st weeks (p<0.01), while in the postpartum period values tended to those registered at the beginning of pregnancy. No changes have been found for the phase angle in both approaches, indicating that ECW/ICW ratio remained constant. Conclusions: among physiological pregnancies, bioelectric values showed a coherent trend and these results represent a first contribution to support routine exams, leading to an early detection of anomalous values potentially correlated to pathologies.

Impedance Analysis to Evaluate Nutritional Status in Physiological and Pathological Conditions

“… Sports medicine: checking body hydration and monitoring changes in FFM and fat mass (FM); detecting changes as a result of intense training or inadequate diet [ 11 ]. Obstetrics and gynecology: monitoring weight changes and water retention in pregnancy and menopause [ 12 ]. Geriatrics: monitoring changes in weight and dehydration with aging, with an assessment of dietary and hydration needs.…”

“…Obstetrics and gynecology: monitoring weight changes and water retention in pregnancy and menopause [ 12 ].…”

The bioelectrical impedance analysis (BIA) international database: aims, scope, and call for data

“…A second approach focuses on direct measures provided by BIA that have been widely used to explore malnutrition, growth and development, athletic performance, sexual dimorphism, pregnancy, and ageing in several populations [47][48][49][50][51][52][53][54][55] . Indeed, the raw BIA parameter phase angle (PhA), representing the arc tangent of Xc/R, is a compound indicator of the distribution between intra and extracellular fluids and of body cell mass 8, 53 .…”

Total and segmental phase angle in a cohort of hospitalised patients with COVID-19: mortality prediction and changes throughout hospitalisation

“…The results are obtained in degrees (°) and interpreted according to the reference values per population. In the last few years, the bioelectrical impedance vector analysis (BIVA), also called the graphical R/Xc (RXc) method, has been used mainly in healthy athlete populations but also in some clinical situations (14)(15)(16)(17) . This method uses height to standardise R and Xc (R/height and Xc/height, respectively), which are components of the impedance vector on an RXc graph, to compare the individual's measurement to that of a healthy population.…”