Urine color as an indicator of urine concentration in pregnant and lactating women

Amy L. McKenzie, Colleen X. Muñoz, Lindsay A. Ellis, Erica T. Perrier, Isabelle Guelinckx, Alexis Klein, Stavros A. Kavouras, Lawrence E. Armstrong

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Aim: Urine concentration measured via osmolality (UOSM) and specific gravity (USG) reflects the adequacy of daily fluid intake, which has important relationships to health in pregnant (PREG) and lactating (LACT) women. Urine color (UCOL) may be a practical, surrogate marker for whole-body hydration status. Purpose: To determine whether UCOL was a valid measure of urine concentration in PREG and LACT, and pair-matched non-pregnant, non-lactating control women (CON). Methods: Eighteen PREG/LACT (age 31 ± 1 years, pre-pregnancy BMI 24.3 ± 5.9 kg m−2) and eighteen CON (age 29 ± 4 years, BMI 24.1 ± 3.7 kg m−2) collected 24-h and single-urine samples on specified daily voids at five time points (15 ± 2, 26 ± 1, and 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation; CON visits were separated by similar time intervals) for measurement of 24-h UOSM, USG, and UCOL and single-sample UOSM and UCOL. Results: Twenty-four-hour UCOL was significantly correlated with 24-h UOSM (r = 0.6085–0.8390, P < 0.0001) and 24-h USG (r = 0.6213–0.8985, P < 0.0001) in all groups. A 24-h UCOL ≥ 4 (AUC = 0.6848–0.9513, P < 0.05) and single-sample UCOL ≥ 4 (AUC = 0.9094–0.9216, P < 0.0001) indicated 24-h UOSM ≥ 500 mOsm kg−1 (representing inadequate fluid intake) in PREG, LACT, and CON. Conclusions: Urine color was a valid marker of urine concentration in all groups. Thus, PREG, LACT, and CON can utilize UCOL to monitor their daily fluid balance. Women who present with a UCOL ≥ 4 likely have a UOSM ≥ 500 mOsm kg−1 and should increase fluid consumption to improve overall hydration status.

Original languageEnglish (US)
Pages (from-to)355-362
Number of pages8
JournalEuropean Journal of Nutrition
Issue number1
StatePublished - Feb 1 2017
Externally publishedYes


  • Biomarker
  • Fluid intake
  • Hydration status
  • Lactating women
  • Pregnant women
  • Urine color

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


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