title: Fetal scalp blood lactate during second stage of labor: determination of reference values and impact of obstetrical interventions.
abstract: OBJECTIVE
  To determine the reference interval of fetal scalp blood lactate during second stage of labor.
  
  
  METHODS
  Two hundred and fifty-three women in first stage of labor with a reassuring CTG were asked for permission to sample fetal scalp blood during second stage.
  
  
  RESULTS
  In cases with reassuring CTG and five minute Apgar score ≥9, the mean lactate value (±2 SD) was 2.5 mmol/L (lower limit 1.1, higher limit 5.2). The lactate concentration was significantly higher among nulliparous and in cases with use of epidural or oxytocin (p <0.001). There was a moderate positive correlation between scalp lactate values and active pushing time. When parity, epidural, oxytocin and active pushing time were analyzed together, they had equal influence on lactate values (p <0.001). Higher lactate values were associated with intermediate/pathological CTG compared to normal CTG (p <0.001). There was no correlation to gestational age or birthweight (p = 0.72, respectively 0.43).
  
  
  CONCLUSIONS
  The reference interval of fetal scalp lactate during second stage is 1.1-5.2 mmol/L. Parity, use of epidural or oxytocin and the duration of pushing are associated to increased lactate concentration; however, we could not demonstrate any correlation to advancing gestational age or birthweight.
authors.affiliation: a Department of Obstetrics and Gynecology , Skåne University Hospital , Lund , Sweden , and.
authors.forename: Nana
authors.initials: N
authors.lastname: Wiberg
authors.affiliation: b Center for Reproductive Epidemiology, Tornblad Institute, Institution of Clinical Sciences Lund, Lund University , Lund , Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Källén
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005323:Fetal Monitoring; D005865:Gestational Age; D006801:Humans; D007748:Labor Stage, Second / Q000502:physiology*; D019344:Lactic Acid / Q000097:blood*; D008875:Middle Aged; D007744:Obstetric Labor Complications / Q000517:prevention & control*; D010120:Oxytocics / Q000008:administration & dosage; D010121:Oxytocin / Q000008:administration & dosage; D011247:Pregnancy; D012016:Reference Values; D012535:Scalp / Q000098:blood supply*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010120:Oxytocics; D019344:Lactic Acid; D010121:Oxytocin
keywords: Fetal monitoring; fetal scalp blood sampling; labor; lactate; oxytocin; pH; second stage