The correlation between fetal bradycardia area in the second stage of labor and acidemia at birth

Abstract

The bradycardia area in the second stage of labor significantly correlates with an accurate timing of fetal acidemia. Regardless of the cause of the bradycardia, the time for intervention is often short, meaning that any available intervention may be ineffective in preventing acidemia or even injury.

Relationship between Deceleration Areas in the Second Stage of Labor and Neonatal Acidemia

“…Previous studies have suggested a link between fetal hypoxia during labor, especially in the second stage of labor, and fetal distress [5,10]. In turn, fetal hypoxia cause FHR decelerations, each characterized by a duration and a depth.…”

“…Instead, fetal distress can be quantitatively characterized by measuring the pH at birth. Thus, this study followed what done in [10] on a population of 33 pregnant women and attempted a characterization of the relationship between DA measured in the last 60 minutes before delivery and pH at birth on a much larger population. In order to have a homogeneous Fig.…”

“…Receiver operating characteristic (ROC, solid line) with the relative area under curve (AUC) relative to pH at birth. data set that maintains the same study conditions of [10], 433 60-min FHR windows before delivery were selected from of the 552 available at the "CTU -CHB Intrapartum Cardiotocography Database" of Physionet. To be selected, 60-min FHR windows had to have at least 90% available data.…”

“…As in [10], DA calculated for FHR ≤ 90 bpm was correlated with umbilical pH at birth that was used to classify FHR tracings as Cases, when umbilical neonatal pH ≤ 7.1, and Controls, when umbilical neonatal pH > 7.1.…”

“…Indeed, values of the deceleration area (DA), measured as deceleration duration by depth, have been found to be associated to critical fetal outcomes [9]. In 2013, a preliminary study [10] attempted to quantify this phenomenon previously only qualitatively described. The study, accomplished on 33 pregnant women with FHR decelerations in the second stage of labor, reported a significant inverse correlation between DA measured in the last 60 minutes before delivery and umbilical pH at birth, which is considered a measure of fetal distress when ≤ 7.1.…”