The effect of early second stage bradycardia on newborn status.

In the present study 45 patients with intrapartum cardiotocograms showing prolonged fetal bradycardia during the early second stage of labor were included. Bradycardia persisted for 180 s or more with either rapid or prolonged return to baseline, without loss of variability and rise of baseline fetal heart rate (FHR). The mean duration of bradycardia was 5.0 +/- 1.3 min. In the group with normal FHR tracings the rate of normal delivery (73.3%) was significantly higher than that of the group with fetal bradycardia (26.7%, P < 0.0001). We also noted a significantly higher rate of cesarean section (44.4%) in patients with abnormal FHR tracings, compared to that (11.1%) of parturients with normal FHR tracings (P < 0.001). In all cases blood samples were obtained from the umbilical cord artery, immediately after delivery. Only in two cases with abnormal FHR tracing umbilical cord artery was the pH less than 7.20. We conclude that in most cases, prolonged fetal bradycardia in the early second stage with the characteristics described above is well tolerated by a mature fetus.