title: Scalp blood lactate for intra-partum assessment of fetal metabolic acidosis.
abstract: OBJECTIVE
  To study to what extent the fetal scalp blood lactate concentration during labor correlates with fetal scalp pH and base deficit, and metabolic acidosis at birth, and to suggest lactate cut-off values to serve as indicators for either reassurance or immediate intervention.
  
  
  METHODS
  A retrospective observational study.
  
  
  METHODS
  Labor ward at a university medical center.
  
  
  METHODS
  Fetal scalp and cord blood samples with acid-base and lactate values from 486 singleton pregnancies beyond 34 weeks' gestation.
  
  
  METHODS
  The relation between lactate, pH and base deficit (BD) in fetal scalp blood was tested by Spearman's rho correlation coefficient. Lactate cut-off values indicating either reassuring fetal status or immediate intervention were estimated using percentile distribution and compared with pH and BD.
  
  
  METHODS
  Metabolic acidosis, defined as umbilical cord artery pH below 7.05 and BD calculated for the blood compartment above 12 mmol/l.
  
  
  RESULTS
  After 127 (21%) exclusions, 486 cases were available for analysis. Fetal lactate values increased with evolving metabolic acidosis. Lactate concentration correlated with both pH (r=-0.50, p<0.01) and BD (r=0.48, p<0.01). Lactate <5.4 mmol/l indicated reassuring fetal status, whereas lactate ≥6.6 mmol/l indicated metabolic acidosis. Fetal lactate correlated better with either the absence or presence of metabolic acidosis at birth than did fetal pH and BD.
  
  
  CONCLUSIONS
  In the case of a non-reassuring fetal heart rate, fetal scalp blood lactate provides more accurate information on fetal acid-base status than does pH and/or BD.
authors.affiliation: Department of Obstetrics and Gynecology Department of Clinical Chemistry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. a.heinis@obgyn.umcn.nl
authors.forename: Ayesha M F
authors.initials: AM
authors.lastname: Heinis
authors.forename: Marc E
authors.initials: ME
authors.lastname: Spaanderman
authors.forename: Jacqueline M T Klein
authors.initials: JM
authors.lastname: Gunnewiek
authors.forename: Fred K
authors.initials: FK
authors.lastname: Lotgering
mesh_terms: D000046:Academic Medical Centers; D000138:Acidosis / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005323:Fetal Monitoring / Q000379:methods; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007773:Lactates / Q000097:blood* / Q000378:metabolism; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis / Q000379:methods; D012189:Retrospective Studies; D012535:Scalp / Q000098:blood supply* / Q000378:metabolism; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D007773:Lactates; D002245:Carbon Dioxide