Fetal scalp pH during labor: Which threshold for intervention?

Objective. - In case of abnormal fetal heart rate, there is no consensus on the decision threshold pH scalp leading to a rapid birth. The objective of this study was to compare neonatal issues and cesarean rate in two maternity using different decision thresholds of scalp pH. Material and methods. - A comparative retrospective study conducted in two level III maternity units between January 2013 and May 2014, one maternity unit used a decision threshold of 7.20 (maternity unit 7,20), and the other one a threshold of 7.25 (maternity unit 7,25). An adverse neonatal outcome was defined by a composite endpoint of neonatal morbidity. The risk of cesarean was assessed using a multivariate analysis. Results. - One hundred and four patients were included in the maternity unit 7,20 and 163 patients in the maternity 7,25. Adverse neonatal outcome was similar in both maternities (25% vs. 30,1%; P = 0.4). The average pH at birth was similar in both maternities, as well as the Apgar score at 5 minutes and neonatal transfer rates. However, BE <-12 was more frequent in maternity using 7,20 scalp pH threshold (7% vs. 0%; P < 0.01). The cesarean rate was higher in maternity 7,25 (adjusted OR = 2.23 95% CI [1.17-4.25]). Conclusion. - It seems that a decisional threshold fixed to 7,20 could be used reasonably. It could allow to reduce cesarean rate. Other studies are, however, needed to confirm that such threshold of 7,20 does not increase the risk of severe acidosis. (C) 2017 Elsevier Masson SAS. All rights reserved.