title: Relationships between hydration biomarkers and total fluid intake in pregnant and lactating women.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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 UVOLin PREG (P = 0.0017). No significant relationships between TFI and hematological biomarkers existed (P > 0.05).
  
  
  CONCLUSIONS
  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.
authors: Department of Kinesiology, Human Performance Laboratory, University of Connecticut, 2095 Hillside Road, Storrs, CT, 06269-1110, USA. amylmckenzie@gmail.com.
authors: Amy L
authors: AL
authors: McKenzie
authors: Danone Research, RD 128, 91767, Palaiseau, France.
authors: Erica T
authors: ET
authors: Perrier
authors: Danone Research, RD 128, 91767, Palaiseau, France.
authors: Isabelle
authors: I
authors: Guelinckx
authors: Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, 155 Stadium Drive, HPER 321, Fayetteville, AR, 72701, USA.
authors: Stavros A
authors: SA
authors: Kavouras
authors: University of Connecticut Health, Family Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA.
authors: Giselle
authors: G
authors: Aerni
authors: Department of Kinesiology, Human Performance Laboratory, University of Connecticut, 2095 Hillside Road, Storrs, CT, 06269-1110, USA.
authors: Elaine C
authors: EC
authors: Lee
authors: Department of Human Sciences, Ohio State University, PAES Building, 305 W. 17th Ave, Columbus, OH, 43210, USA.
authors: Jeff S
authors: JS
authors: Volek
authors: Department of Human Sciences, Ohio State University, PAES Building, 305 W. 17th Ave, Columbus, OH, 43210, USA.
authors: Carl M
authors: CM
authors: Maresh
authors: Department of Kinesiology, Human Performance Laboratory, University of Connecticut, 2095 Hillside Road, Storrs, CT, 06269-1110, USA.
authors: Lawrence E
authors: LE
authors: Armstrong
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine*; D015992:Body Mass Index; D001942:Breast Feeding; D003681:Dehydration / Q000175:diagnosis / Q000652:urine; D004326:Drinking; D005260:Female; D006801:Humans; D007774:Lactation; D008297:Male; D000074267:Organism Hydration Status; D011247:Pregnancy; D014882:Water-Electrolyte Balance
chemical_list: D015415:Biomarkers
keywords: Blood biomarkers; Breast-feeding; Fluid intake adequacy; Gestation; Hydration status; Urine biomarkers