The fetal electrocardiogram: Relationship with acidemia at delivery

OBJECTIVE: This study was undertaken to analyze the relationship between th e fetal electrocardiogram and arterial pH and base excess at delivery. STUDY DESIGN: In the labor wards of three teaching hospitals a retrospectiv e observational study was conducted on fetal monitor recordings of 679 wome n for whom there was an indication for continuous fetal monitoring during l abor. These women had been recruited as part of either observational studie s or a prospective randomized trial related to the Nottingham fetal electro cardiographic project. Fetal heart and uterine contraction data were obtain ed with the Nottingham fetal electrocardiographic analyzer. Morphologic and time interval analyses of the fetal electrocardiogram were performed. Eval uation was carried out for the last half hour before delivery. Main outcome measures were umbilical arterial pH and base excess at delivery. RESULTS: The study demonstrated a relationship between time interval analys is of the fetal electrocardiogram and a low umbilical arterial pH and base excess at delivery. Analysis of the morphologic characteristics of the feta l electrocardiogram (ST segment and T-wave height) showed no significant re lationship. CONCLUSIONS: Time interval analysis of the fetal electrocardiogram during l abor is related to relative acidemia at delivery.