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United States Department of Agriculture

Agricultural Research Service


item Van Loan, Marta
item Kopp, Lori
item King, Janet
item Wong, William
item Mayclin, Patrick

Submitted to: Journal of Applied Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: The amount of total body water (TBW) increases tremendously during pregnancy. This change in TBW is of great interest to doctors and scientists. Too large an increase can put demands on the body's organs and systems, and in some cases an increased water load may be due to edema. This change is not easy to measure accurately, and we wanted to find the best technique available to do it properly. We examined the accuracy of a technique called bioimpedance spectroscopy to estimate fluid volumes before, during and after pregnancy in 10 healthy adult women. Our results suggest that this technique may be useful in estimating volumes of extracellular fluid and TBW during pregnancy.

Technical Abstract: The increase in body water during pregnancy is responsible for the largest portion of weight gain and is of interest to clinical practitioners. However, assessing changes in body fluids is not easily accomplished during pregnancy. The purpose of this study was to examine the accuracy of bioelectrical impedance spectroscopy for estimating fluids volumes before, during and after pregnancy. Ten healthy adult women were recruited for the study. Total body water (TBW) and extracellular fluid (ECF) volume were measured at baseline (preconception); 8-10, 24-26, and 34-36 wk of gestation; and 4-6 wk postpartum of deuterium oxide and NaBr dilution, respectively. Estimates of TBW and ECF were also obtained by bioimpedance spectroscopy (BIS). At baseline, mean values for dilution and BIS estimates of TBW and ECF were 33.2 +/- 4.6 (SD) vs. 31.6 +/- 6.2 liters and 15.2 +/- 1.3 vs. 16.9 +/- 2.3 liters, respectively. TBW and ECF estimated by BIS were not significantly different from the dilution values at any time point. These results suggest that BIS may be useful in estimating volumes of ECF and TBW during pregnancy.

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