The use of fetal foot length to determine stillborn gestational age in Vietnam

Abstract

Objective To assess the use of fetal foot length for predicting gestational age in stillborn fetuses in Vietnam and the ability of this measurement to differentiate early from late fetal deaths. Methods In a prospective case series, gestational age was determined from either certain first day of last menstrual period or early ultrasound scan. Foot length was measured, with a non-elastic tape measure, from the heel to the tip of the longest toe. Agreement of observed and predicted foot length for gestational age was tested, as well as the influence of fetal characteristics. Results Accurate gestational age and foot length were available for 52 of 107 participants. Strong agreement was demonstrated between observed and predicted values of foot length across gestations (95% confidence interval, –4.7 to 4.3 weeks). Accuracy of fetal foot length in predicting gestational age was affected by growth restriction but not fetal gender, maceration, or congenital anomalies. Fetal foot length of 55 mm or greater demonstrated a sensitivity and specificity of 88% in identifying late fetal deaths. Conclusion Foot length is a good differentiator of early and late fetal death, which is important for the global recording of the number of stillbirths.