[Heart rate accelerations in the fetus during fetal blood sampling sub partu]

Fetal heart rate acceleration is often observed when fetal blood sampling (FBS) is performed during labour. The aim of this study was to examine the influence of the occurrence of a fetal heart rate acceleration on the fetal condition immediately after the FBS incision during labour. 117 pregnant patients with a total of 210 FBS were included in the study. Particular attention was given as to whether an acceleration > or = 15 bpm and > or = 15 sec occurred immediately after the FBS incision. So 2 groups were formed: reactive (159 cases with acceleration) and non-reactive (51 cases without acceleration). No FBS acceleration was observed in any case with acidosis during labour. Therefore the occurrence of an FBS acceleration can be regarded as a reliable predictor of a fetal pH value of > or = 7.20 during labour. The test sensitivity amounts to 77% and the specificity and the positive predictive value are 100%. If an acceleration occurred immediately after the FBS incision, in 6% of the cases (negative predictive value) an acidosis with a pH value of < 7.20 was registered. The cesarean section rate increases by more than double from 13% to 33% when no FBS acceleration occurs.