Bioelectrical impedance vector (BIVA) reference values for healthy term newborns 1-2 days old.

Abstract

Background: Bioelectrical impedance vector analysis (BIVA) is a valuable tool for assessing individuals' body fluids and nutritional status by examining the impedance vector's position on the mean reference impedance vector tolerance ellipses from healthy populations. Nevertheless, differences in BIVA tolerance ellipses have been reported between populations with different ethnicities, body mass index (BMI), sex, and age.

Aim: To construct BIVA reference values for healthy newborns aged 1-2 days born to term and compare them to those previously reported for newborns from different populations.

Methods: A cross-sectional study was conducted using bioelectrical impedance data collected within the first 48 hours after birth from healthy, term newborns with healthy mothers. The mean impedance vector 50%, 75%, and 95% tolerance ellipses were constructed and compared with those previously reported for other newborn populations.

Results: The healthy newborns' mean impedance vector showed significant differences between populations, with similarities observed only between our newborn population and one of the four previously reported populations. No vector displacement was found related to the mode of delivery or sex of the newborns.

Conclusions: The mean impedance vector tolerance ellipses for healthy term newborn population aged 1-2 days were constructed. Our results show that there are differences in the mean impedance vector compared to other BIVA newborn studies, which could result from the influence of ethnic background on BIVA tolerance ellipses or be due to differences in the technique for BIA assessment.