Fetal Scalp Lactate Microsampling for Non-Reassuring Fetal Status during Labor: A Prospective Observational Study

Abstract

Objective: The aim was to study the predictive value and feasibility of fetal scalp lactate microsampling in the management of non-reassuring fetal status during labor. Methods: A prospective observational study was conducted on cord blood gas samplings from 7,617 singleton and cephalic deliveries at ≧37 weeks of gestation. In this population, 450 fetal scalp blood samples (FBS) were performed for abnormal fetal heart rate (FHR) patterns. Microvolume scalp lactate measurements were compared to scalp pH, neonatal cord blood gas parameters (pH, lactate, base deficit) and the Apgar score. Results: Scalp lactate correlated significantly with scalp pH (r = –0.56, p = 0.001), umbilical artery pH (r = –0.39, p = 0.03), umbilical artery lactate (r = 0.48, p = 0.01) and umbilical artery base deficit (r = 0.51, p = 0.01), but not with Apgar scores. Using receiver operating characteristic curves, a scalp lactate cutoff value of 5 mmol/l was the most predictive for neonatal acidosis. Sampling failure with scalp lactate was inferior to scalp pH (1.3 vs. 14%, p < 0.001). Conclusion: Lactate microsampling in fetal scalp blood was found to be an attractive alternative to pH analysis and a useful 2nd-line tool for monitoring fetal asphyxia during labor.

FIGO consensus guidelines on intrapartum fetal monitoring: Adjunctive technologies

“…In about 10% of attempts no pH information is obtained owing to blood clotting within the capillary, insufficient blood obtained, air bubbles inside the capillary, or a blood gas measurer that is calibrating at the time the sample needs to be analyzed. The failure rate when lactate analysis is performed is lower, at about 1.5% [14,15]. This is because for lactate analysis, approximately 5 μL is needed as compared with 50 μL that is required for blood gas assessment [15][16][17].…”

“…The failure rate when lactate analysis is performed is lower, at about 1.5% [14,15]. This is because for lactate analysis, approximately 5 μL is needed as compared with 50 μL that is required for blood gas assessment [15][16][17].…”

Neonatal outcome and delivery mode in labors with repetitive fetal scalp blood sampling

“…The use of FBS varies largely between countries, with reported frequencies between 3 and 15% in some countries [1,19,20], and essentially none in other. The attitude toward the use of FBS can be considered liberal at the labor ward where this study was conducted, with a frequency of 11% of all labors, but is comparable to other countries where FBS is a part of intrapartum fetal surveillance routines [19].…”

Place du microdosage des lactates au scalp et au cordon devant des anomalies du rythme cardiaque fœtal pendant le travail. Étude prospective sur 162 patientes

“…• entre le pH et les lactates au scalp : r = -9 dans notre étude, r = -0,43 pour Westgren [17], r = -0,43 pour Nordström [18], r = -0,28 pour Brand [12], r = -0,54 et -0,56 pour Ramanah [13,19], r = -0,53 pour Kruger [6], r = -0,69 pour Linet [20] ; • entre le pH et les lactates eu cordon : r = -0,83 dans notre étude, r = -0,61 pour Nordström [21], r = -0,69 pour Boog [22], r = -0,55 pour Kruger [6], r = -0,64 pour Brand [12], r = -0,53 pour Martin [23], r = -0,73 pour Gjerris [24], r = 0,48 pour Ramanah [19] ; • entre les lactates au scalp du dernier prélèvement et les lactates au cordon : r = 0,75 dans notre série, r = 0,65 pour Kruger [25], r = 0,49 pour Borruto [26], r = 0,31 pour Brand [12], r = 0,49 pour Ramanah [13].…”