Relationships between hydration biomarkers and total fluid intake in pregnant and lactating women

Amy L. McKenzie, Erica T. Perrier, Isabelle Guelinckx, Stavros A. Kavouras, Giselle Aerni, Elaine C. Lee, Jeff S. Volek, Carl M. Maresh, Lawrence E. Armstrong

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Introduction: Previous research established significant relationships between total fluid intake (TFI) and urinary biomarkers of the hydration process in free-living males and females; however, the nature of this relationship is not known for pregnant (PREG) and lactating (LACT) women. Purpose: To determine the relationship between urinary and hematological hydration biomarkers with TFI in PREG and LACT. Methods: Eighteen PREG/LACT (age: 31 ± 3 years, pre-pregnancy BMI: 24.26 ± 5.85 kg m−2) collected 24-h urine samples, recorded TFI, and provided a blood sample at 5 time points (15 ± 2, 26 ± 1, 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation); 18 pair-matched non-pregnant (NP), non-lactating (NL) women (age: 29 ± 4 years, BMI: 24.1 ± 3.7 kg m−2) provided samples at similar time intervals. Twenty-four-hour urine volume (UVOL), osmolality (UOSM), specific gravity (USG), and color (UCOL) were measured. Hematocrit, serum osmolality (SOSM), and serum total protein (STP) were measured in blood. Results: Significant relationships were present between TFI and urinary biomarkers in all women (P < 0.004); these relationships were not different between PREG and NP, and LACT and NL, except UVOL in PREG (P = 0.0017). No significant relationships between TFI and hematological biomarkers existed (P > 0.05). Conclusion: Urinary biomarkers of hydration, but not hematological biomarkers, have a strong relationship with TFI in PREG, LACT, NP, and NL women. These data suggest that urinary biomarkers of hydration reflect TFI during pregnancy and breast-feeding.

Original languageEnglish (US)
Pages (from-to)2161-2170
Number of pages10
JournalEuropean Journal of Nutrition
Issue number6
StatePublished - Sep 1 2017
Externally publishedYes


  • Blood biomarkers
  • Breast-feeding
  • Fluid intake adequacy
  • Gestation
  • Hydration status
  • Urine biomarkers

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


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