Uteroplacental and fetal haemodynamics during extradural anaesthesia for caesarean section.

We have studied the effects of extradural anaesthesia with bupivacaine (plain) in eight healthy parturients undergoing elective Caesarean section, on blood flow in maternal uterine and placental arcuate arteries and in fetal umbilical, renal and middle cerebral arteries, using a colour Doppler technique. Simultaneously, fetal myocardial function was investigated by M-mode echocardiography. Maternal and fetal blood velocity waveform indices did not change significantly. We found no changes in fetal myocardial function with extradural anaesthesia, except for an increase in the right ventricular inner end-diastolic dimensions. These results suggest that extradural anaesthesia has no detrimental effects on uteroplacental and fetal circulations in the uncomplicated pregnancy when maternal hypotension is avoided with rapid prehydration.