Effects of epidural analgesia on uterine artery Doppler in labour

Abstract

Background: The effects of epidural anaesthesia on maternal uteroplacental blood flow in the presence of uterine contractions remain unclear. The aim of our study was to evaluate the effects of epidural analgesia with bolus doses on uterine artery pulsatility index (UtA-PI) during labour.

Methods: In a prospective case-control study, UtA-PI was measured during uterine contraction and relaxation in nulliparous women in active labour with (epidural group) and without (control group) epidural analgesia. Patients in the two groups were matched for gestational age at delivery, American Society of Anesthesiologists physical status score, and cervical dilatation at the beginning of labour. In the epidural group, an epidural catheter was placed after prehydration with 500 ml i.v. saline, and sufentanil 2 μg ml⁻¹ (5 ml) and ropivacaine 1 mg ml⁻¹ (20 ml) were administered. UtA-PI was measured before (T0), 30 min (T30), and 90 min (T90) after the first administration of epidural analgesic drugs, during both uterine relaxation and contraction.

Results: Fifty-two patients were included in the study, 33 in the epidural group and 19 in the control. UtA-PI was significantly higher in the epidural compared with the control group, only at T30 and during contraction. There were no differences in the rate of oxytocin augmentation, mode of delivery, birth weight, and umbilical artery pH between the two groups.

Conclusions: Epidural analgesia using ropivacaine 1 mg ml⁻¹ (20 ml) significantly reduced placental blood flow only transiently during uterine contraction 30 min after the injection. These changes did not seem to affect neonatal outcomes.