A comparative study of the safety of 0.25% levobupivacaine and 0.25% racemic bupivacaine for paracervical block in the first stage of labor

Abstract

The objective of the study was to evaluate and compare the safety of levobupivacaine and racemic bupivacaine for paracervical block (PCB) in the first stage of labor after uncomplicated pregnancy. Forty women in an open pilot study and 397 women in a double-blind randomized study received PCB for pain relief in the first stage of labor, either with 25 mg of levobupivacaine or with 25 mg of racemic bupivacaine. The incidence of cardiotocographic pathology was compared between the groups using Fisher's exact test. The 95% confidence intervals for the between-group difference were calculated by Newcombe's method. In the randomized double-blind study, the incidence of any pathological result in cardiotocography (CTG) was 10.4% in the levobupivacaine group and 12.8% in the racemic bupivacaine group. The incidence of fetal bradycardia in the groups was 2.6 and 3.8%, respectively. All the cardiotocographic changes were transient, and no operative intervention was indicated because of CTG. No difference in the analgesic effect between the drugs was found. Most of the parturients in the levobupivacaine group (97%) and in the racemic bupivacaine group (96%) had spontaneous vaginal delivery. Neonatal outcome was good in both groups. No difference in cardiotocographic pathology was found between PCB with levobupivacaine compared with PCB with racemic bupivacaine. The incidence of bradycardia was low. PCB was found to be a safe pain-relief method for low-risk parturients.