title: Bioelectrical impedance analysis in pregnancy: reference ranges.
abstract: OBJECTIVE
  To generate reference values for bioelectrical impedance analysis (BIA) in a German collective of healthy pregnant women.
  
  
  METHODS
  A total of 90 women with a singleton gestation from 23+0 to 40+6 weeks of pregnancy were enrolled from April 2012 until May 2013. Each week of gestation was represented by the same number of women (n=5). Mean BIA indices were generated for all patients and according to gestational age so that three collectives <30, 30 to 35 and >35 weeks of gestation were formed. Multiple regression analysis was implemented using maternal height, weight, body-mass index, gestational age, hematocrit and abdominal circumference to generate formulae to calculate individualized reference values for resistance, reactance, phase angle, height(2)/resistance, and total body water adjusted for gestation.
  
  
  RESULTS
  Individualised reference values using the new formulae led to results which are more accurate than general mean values or mean values corresponding to the gestational age only.
  
  
  CONCLUSIONS
  As far as we are aware of the present study is the first to report reference values for BIA indices in a German collective of healthy pregnant women. The new formulae generated by multiple regression analysis enabled for assessment of individualized reference values for BIA indices.
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Centre Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany. sebastian.berlit@umm.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Berlit
authors.forename: Benjamin
authors.initials: B
authors.lastname: Tuschy
authors.forename: Marlène
authors.initials: M
authors.lastname: Stojakowits
authors.forename: Christel
authors.initials: C
authors.lastname: Weiss
authors.forename: Hans
authors.initials: H
authors.lastname: Leweling
authors.forename: Marc
authors.initials: M
authors.lastname: Sütterlin
authors.forename: Sven
authors.initials: S
authors.lastname: Kehl
mesh_terms: D000293:Adolescent; D000328:Adult; D017097:Electric Impedance; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000502:physiology*; D011446:Prospective Studies; D012016:Reference Values; D012879:Skin Physiological Phenomena; D015430:Weight Gain; D055815:Young Adult
keywords: Bioelectrical impedance analysis; pregnancy; reference ranges