LOW-DOSE BUPIVACAINE FENTANYL EPIDURAL INFUSIONS IN LABOR AND MODE OFDELIVERY

The aim of this study was to determine the effect on the instrumental delivery rate of two different concentrations of bupivacaine combined with fentanyl in epidural infusions during labour. Only primiparous wo men in whom a spontaneous vaginal delivery was anticipated, were inclu ded bl the study. Those women receiving a higher concentration of bupi vacaine and therefore a greater amount of local anaesthetic agent duri ng labour were significantly more likely to have an instrumental deliv ery with Kielland's rotational forceps (p < 0.01). Those women receivi ng a lower concentration and smaller amount of bupivacaine were signif icantly mole likely to have an instrumental delivery with Neville-Barn es forceps (p < 0.05). This provides evidence to support the theory th at epidural analgesia may contribute to inadequate rotation of the pre senting fetal part due to weakened pelvic floor muscles and that this is more likely to occur when higher concentrations of bupivacaine are used and a greater degree of motor block occurs.