Fetal scalp blood lactate during second stage of labor: determination of reference values and impact of obstetrical interventions

• Published in: The journal of maternal-fetal & neonatal medicine Vol. 30; no. 5; pp. 612 - 617
• Main Authors: Wiberg, Nana, Källén, Karin
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 04-03-2017
• Subjects: Adolescent; Adult; Biomarkers - blood; Clinical Medicine; Female; Fetal Blood - chemistry; Fetal Monitoring; fetal scalp blood sampling; Gestational Age; Humans; Klinisk medicin; labor; Labor Stage, Second - physiology; lactate; Lactic Acid - blood; Medical and Health Sciences; Medicin och hälsovetenskap; Middle Aged; Obstetric Labor Complications - prevention & control; Obstetrics, Gynecology and Reproductive Medicine; Oxytocics - administration & dosage; oxytocin; Oxytocin - administration & dosage; Pregnancy; Reference Values; Reproduktionsmedicin och gynekologi; Scalp - blood supply; second stage; Young Adult; oxytocin; second stage; pH; fetal scalp blood sampling; lactate; Fetal monitoring; labor
• ISSN: 1476-7058; 1476-4954
• DOI: 10.1080/14767058.2016.1181167

Objective: To determine the reference interval of fetal scalp blood lactate during second stage of labor.
Material: 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.