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Evaluation of 24h Urine Volume as an Indicator of Uosm:Posm Ratio and Free Water Clearance in Pregnant Women
Author(s) -
McKenzie Amy,
Muñoz Colleen,
Perrier Erica,
Jimenez Liliana,
Armstrong Lawrence
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.810.1
Subject(s) - urine , urine osmolality , urine specific gravity , urology , medicine , pregnancy , chemistry , endocrinology , zoology , biology , genetics
Free water clearance (FWC), calculated from urine and blood measures, is often used to describe body water balance via the kidney's regulation of diuresis. The purpose of this investigation was to evaluate if 24h urine volume was a significant predictor of the urine‐to‐serum osmolality ratio (USR) and FWC in pregnant (PREG) and non‐pregnant (CON) women. Methods: 24h urine volume (U vol ), 24h urine osmolality, and serum osmolality were measured in 18 PREG (age: 31±3y, height: 1.66±0.07m; pre‐pregnancy weight: 68.08±18.92kg) women at the end of the first, second, and third trimesters, and in 18 CON (age: 29±4y; height: 1.64±0.08m; weight: 64.83±13.84kg) at similar time intervals for calculation of USR and FWC. Relationships between 24h U vol and USR, as well as 24h U vol and FWC, were evaluated with linear regression. Results: 24h U vol was a significant predictor of USR (PREG: r 2 =0.61, p<0.0001; CON: r 2 =.50, p<0.0001) and FWC (PREG: r 2 =0.70, p<0.0001; CON: r 2 =.45, p<0.0001); relationships were similar between PREG and CON for 24h U vol and USR (p=0.24) and for 24h Uvol and FWC (p=0.90). Conclusion The relationships between 24h U vol and both USR and FWC are maintained throughout pregnancy. This suggests that 24h U vol may provide adequate diagnostic accuracy for the evaluation of body water balance during pregnancy. Supported by Danone Research.