Interobserver reliability of fetal heart rate pattern interpretation using NICHD definitions

Objective To evaluate the interobserver reliability of fetal heart rate (FHR) pattern definition and interpretation assessed by physicians at various levels of training using standard Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) definitions and standard principles of interpretation. Study Design We conducted an interrater reliability study of the intrapartum FHR tracings of 32 singleton term pregnancies at Los Angeles County–University of Southern California (LAC + USC) Medical Center. Analysis included the 5 hours immediately preceding delivery, divided into 10- minute segments. A medical student, resident, and three attending physicians evaluated the same set of FHR tracings. Interobserver agreement was assessed using the free-marginal kappa coefficient. Results Reviewers demonstrated substantial to excellent agreement on baseline rate (κ = 0.97), moderate variability (κ = 0.80), accelerations (κ = 0.62), decelerations (κ = 0.63), category (κ = 0.68), and the ability to identify the presence of either moderate variability or accelerations (κ = 0.82). Conclusions Interobserver agreement was significantly higher on all components of FHR definition and interpretation than previously expected. Standardization of FHR definitions and interpretation may improve interobserver reliability and patient safety.