MATERNAL POSITIONING AFFECTS FETAL HEART-RATE CHANGES AFTER EPIDURAL ANALGESIA FOR LABOR

Adverse fetal heart rate (FHR) changes suggestive of fetal hypoxia are seen in patients with normal term pregnancies after initiation of epi dural block for labour analgesia. It was our hypothesis that, in some parturients, these changes were a consequence of concealed aortocaval compression resulting in decreased uterine blood flow. We expected tha t the full lateral position compared with the wedged supine position w ould provide more effective prophylaxis against aortocaval compression . To test our hypothesis we studied the role of maternal positioning o n FHR changes during onset of epidural analgesia for labour. Eighty-ei ght ASA Class I or II term parturients were randomized into two groups . those to be nursed in the wedged supine position and those to be nur sed in the full lateral position during induction of an epidural block . External FHR monitoring was employed to assess the fetal response to initiation of labour epidural analgesia. Epidural catheters were site d with the parturients in the sitting position and the patients then a ssumed the study position. After a negative test dose, a standardized regimen of bupivacaine 0.25% was employed to provide labour analgesia. The quality and efficacy of the block were using VAS pain scores moto r block scores and sensory levels. The results demonstrated that there was no difference in the quality of analgesia provided nor in the inc idence of asymmetric blocks. There was no difference in the observed i ncidence of FHR changes occurring during the initiation of the epidura l block. However, six of 38 women (15%) nursed in the wedged supine po sition had severe FHR decelerations compared with none in the patients nursed in the full lateral position (P < 0.05). We recommend the use of the full lateral position to nurse women in labour during the initi ation of labour epidural analgesia.