Fetal heart rate acceleration with fetal blood sampling

One hundred three fetal heart rate (FHR) tracings in term fetuses with simultaneous fetal blood pH sampling were reviewed. In 71 fetuses accelerations were present in direct response to blood sampling or within 30 minutes of the sampling procedure, and in 70 of these the pH was above 7.20. Of 32 fetuses without FHR acceleration during fetal blood sampling, seven had pH values below 7.20, and in five of these the values were confirmed by cord pH measurement.