Computerized analysis of fetal heart rate changes after antepartum external cephalic version

To assess the fetal heart rate (FHR) changes following external cephalic version using a computerized FHR monitor.

We performed 116 external cephalic versions on 106 pregnant women at 36-40 weeks' gestation. Tocolysis (magnesium sulfate) was given to 39 patients (34%). Computerized FHR monitoring was performed for 20-30 minutes before and for 20-30 minutes after the procedure. In addition, we analyzed the results of the FHR tracing obtained during the first 10 minutes following the procedure.

External cephalic version was successful in 40% of the patients. In the group of patients who were not treated with magnesium sulfate, FHR variation and the number of accelerations per 10 minutes were significantly reduced during the first 10 minutes following the procedure as compared with those factors on the FHR tracings obtained before or 20-30 minutes following the procedure (P < .05). In the group of patients who were treated with magnesium sulfate, FHR variation and the number of accelerations per 10 minutes were significantly reduced before and 10 minutes after the procedure as compared with the FHR tracings obtained 20-30 minutes following the procedure (P < .05). In both groups the basal FHR was significantly lower during the first 20-30 minutes following the procedure (P < .05). FHR decelerations were observed following the procedure in only two patients. None of the 106 fetuses had a low Apgar score or were admitted to the neonatal intensive care unit.

External cephalic version appears to be safe for the mother and fetus, although transient FHR changes may occur following the procedure.