Can we improve our ability to interpret category II fetal heart rate tracings using additional clinical parameters?

Abstract

This study examined predictive factors, in addition to Category II Fetal Herat Rate (FHR) monitoring that might imply fetal acidosis and risk of asphyxia. This retrospective cohort study compared three groups of patients with Category II FHR monitoring indicating need for imminent delivery. Groups were divided based on fetal cord blood pH: pH≤7.0, 7.0<pH<7.2 and pH≥7.2. Demographics, medical history, delivery data and early neonatal outcomes were reviewed. The cohort included 417 women. Nine (2.2%) had cord pH≤7.0, 105 (25.2%) pH 7.0 to 7.2 and 303 (72.6%) ad pH≥7.2. Background characteristics, pregnancy follow-up and intrauterine fetal evaluation prior to delivery were similar in all groups. As expected, more patients in the low pH group had cesarean section (55.6%), than vaginal delivery or vacuum extraction (p=0.02). Five-minute Apgar scores were similar in all groups. This retrospective study did not detect a specific parameter that could help predict the prognosis of fetal acidosis and risk of asphyxia. As we only included patients with a Category II tracing that was worrisome enough to lead to imminent delivery, it is reasonable to believe that this is due to patient selection, meaning that when the Category II FHR results in decision for prompt delivery, there is no added value in additional clinical characteristics. The evaluation should be expanded to all patients with Category II tracing for better interpretation tools for Category II FHR monitors, as well as a larger study population.