title: [Normal value curves for intrauterine fetal blood gas and acid-base parameters in the 2nd and 3rd trimester].
abstract: OBJECTIVE
  The aim of the study was to establish reference ranges for fetal blood gases and acid-base balance for the second half of the gestation.
  
  
  METHODS
  155 appropriate-for-gestational-age fetuses between 18 and 39 weeks of gestation underwent a diagnostic cordocentesis. From a specimen obtained from umbilical venous blood the acid-base balance and blood gases were evaluated using an AVL 995 blood gas analyzer. In detail, pH, oxygen partial pressure, and carbon dioxide partial pressure were measured and oxygen saturation, bicarbonate concentration and base excess calculated. Thereafter, a linear regression for gestational age was calculated and the 95% confidence interval established.
  
  
  RESULTS
  pH, oxygen partial pressure, and oxygen saturation showed a significant decrease with advancing gestational age, whereas the carbon dioxide partial pressure increased. The ranges of bicarbonate and base excess did not differ significantly.
  
  
  CONCLUSIONS
  The results give information about blood gases in the fetus under physiological conditions, and the reference ranges can be used for comparison in fetuses at high risk of hypoxia or acidemia.
authors.affiliation: Abteilung Pränatale Diagnostik und Therapie, Universitäts-Frauenklinik der Charité, Humboldt-Universität Berlin, Deutschland.
authors.forename: B
authors.initials: B
authors.lastname: Schröter
authors.forename: R
authors.initials: R
authors.lastname: Chaoui
authors.forename: E
authors.initials: E
authors.lastname: Glatzel
authors.forename: R
authors.initials: R
authors.lastname: Bollmann
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D002245:Carbon Dioxide / Q000097:blood*; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010100:Oxygen / Q000097:blood*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012016:Reference Values
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
vernacular_title: Normwertkurven für intrauterine fetale Blutgas- und Säure-Basen-Parameter im 2. und 3. Trimenon.