Human umbilical artery flow velocity waveforms before and after regional anesthesia for cesarean section.

The umbilical artery waveform was assessed in 18 normal nonlaboring patients before and after full surgical epidural anesthesia for repeat cesarean section. Using range-gated pulsed Doppler ultrasound, we found that the waveform analysis of the umbilical artery close to its placental insertion did not change significantly. These results suggest that no deleterious effect on fetoplacental circulation occurs with this form of anesthesia as long as maternal blood pressure is normal.