Antenatal prediction of fetal pH in growth restricted fetuses using computer analysis of the fetal heart rate

We tested the accuracy of a mathematical model based on computer analysis of the fetal heart rate tracing in predicting umbilical artery pH at birth. In a previous report based on data on 38 growth-restricted fetuses, the second-order polynomial regression equation, umbilical artery pH = 7,28 + 0.002 (duration of episodes of low variation in minutes) + 0.00009 (duration of episodes of low variation in minutes)2, was retrospectively found to be the best model for the prediction of umbilical artery pH at birth. In the present study, this formula was prospectively tested in 29 growth restricted fetuses between 26 and 37 weeks of gestation from pregnancies with abnormal uterine and/or umbilical artery Doppler velocimetry. Computer analysis of the fetal heart rate tracing of 1 hour duration was performed within 1.5–6 hours of cesarean birth prior to the onset of labor. Umbilical artery cord blood was collected at birth with pH determined within 5 minutes of collection. Acidemia was defined as umbilical artery ...