Epidurals do not lead to more caesarean sections, study shows
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《英国医生杂志》
Combined spinal and epidural analgesia given early in labour is no more likely than systemic opioid analgesia to be associated with delivery by caesarean section, according to a US study published this week. But it does provide better pain relief and shorter duration of labour, the research showed.
The study, carried out by a group at Northwestern University, Chicago, looked at 750 nulliparous women who went into labour spontaneously at full term, with cervical dilation less than 4 cm (New England Journal of Medicine 2005;352:655-65). The researchers recruited the women by approaching all healthy women with term, singleton pregnancies who presented in spontaneous labour, or with spontaneous rupture of membranes, at one hospital (Prentice Women抯 Hospital in Chicago) between November 2000 and December 2003 and who asked for anaesthesia. These women were asked if they would like to participate in the trial. Exclusion criteria included non-vertex presentation, scheduled induction of labour, any contraindication to opioid analgesia, and cervical dilation greater than or equal to 4 cm.
Participants were randomised to receive spinal fentanyl (injected into the fluid surrounding the spinal cord) or systemic hydromorphone at their first request for anaesthesia. The women who were given spinal fentanyl were given epidural analgesia on their second request for analgesia. This was administered intrathecally into the space between the spinal canal wall and the sheath covering the spinal cord. The women who were given systemic hydromorphone were also given epidural analgesia, either at their third request for analgesia or once cervical dilation was 4 cm or greater.
The study results showed no difference between the groups in the rates of caesarean section. Sixty five of the 366 women (18%) in the intrathecal analgesia group and 75 of the 362 women (21%) in the systemic analgesia group had a delivery by caesarean section (95% confidence interval for the difference - 9.0% to 3.0% (P=0.31)).
However, the median time from start of analgesia to complete dilation was shorter in women who were given intrathecal analgesia (295 minutes versus 385 minutes, difference 90 minutes (95% confidence interval 35 to 123 minutes; P<0.001)), as was time to vaginal delivery (398 minutes versus 479 minutes, difference 81 minutes (28 to 123 minutes; P<0.001)). Self reported pain scores were also lower after intrathecal analgesia (2 points versus 6 points on a visual analogue scale from 0 to 10, difference 4 points (3 to 5 points; P<0.001)). The incidence of poorer Apgar scores (<7) in neonates 1 minute after delivery was higher in the systemic analgesia group (24.1% versus 16.6%, difference 7% (1% to 13%; P=0.01)).
Cynthia Wong, associate professor of anaesthesiology at Northwestern University抯 Feinberg School of Medicine, Chicago, USA, and lead author of the study, said: "The results of this randomised trial suggest that nulliparas in spontaneous labour or with spontaneous rupture of membranes who request pain relief early in labour can receive spinal or epidural analgesia at that time without adverse consequences." She said current US guidelines that recommend delaying use of epidural analgesia should be changed. "If women think they may want an epidural at some stage, there is no point in delaying and using systemic opioids first. We can just go ahead with an epidural without increasing the risk of caesarean delivery."
However, she acknowledged several limitations to the study, including the fact that different obstetric providers and management styles (including patterns of oxytocin use) may have influenced labour outcomes. In addition, the study was not conducted blind. She considered it unlikely, however, that knowledge of the type of analgesia biased obstetricians?decisions about mode of delivery.(London Susan Mayor)
The study, carried out by a group at Northwestern University, Chicago, looked at 750 nulliparous women who went into labour spontaneously at full term, with cervical dilation less than 4 cm (New England Journal of Medicine 2005;352:655-65). The researchers recruited the women by approaching all healthy women with term, singleton pregnancies who presented in spontaneous labour, or with spontaneous rupture of membranes, at one hospital (Prentice Women抯 Hospital in Chicago) between November 2000 and December 2003 and who asked for anaesthesia. These women were asked if they would like to participate in the trial. Exclusion criteria included non-vertex presentation, scheduled induction of labour, any contraindication to opioid analgesia, and cervical dilation greater than or equal to 4 cm.
Participants were randomised to receive spinal fentanyl (injected into the fluid surrounding the spinal cord) or systemic hydromorphone at their first request for anaesthesia. The women who were given spinal fentanyl were given epidural analgesia on their second request for analgesia. This was administered intrathecally into the space between the spinal canal wall and the sheath covering the spinal cord. The women who were given systemic hydromorphone were also given epidural analgesia, either at their third request for analgesia or once cervical dilation was 4 cm or greater.
The study results showed no difference between the groups in the rates of caesarean section. Sixty five of the 366 women (18%) in the intrathecal analgesia group and 75 of the 362 women (21%) in the systemic analgesia group had a delivery by caesarean section (95% confidence interval for the difference - 9.0% to 3.0% (P=0.31)).
However, the median time from start of analgesia to complete dilation was shorter in women who were given intrathecal analgesia (295 minutes versus 385 minutes, difference 90 minutes (95% confidence interval 35 to 123 minutes; P<0.001)), as was time to vaginal delivery (398 minutes versus 479 minutes, difference 81 minutes (28 to 123 minutes; P<0.001)). Self reported pain scores were also lower after intrathecal analgesia (2 points versus 6 points on a visual analogue scale from 0 to 10, difference 4 points (3 to 5 points; P<0.001)). The incidence of poorer Apgar scores (<7) in neonates 1 minute after delivery was higher in the systemic analgesia group (24.1% versus 16.6%, difference 7% (1% to 13%; P=0.01)).
Cynthia Wong, associate professor of anaesthesiology at Northwestern University抯 Feinberg School of Medicine, Chicago, USA, and lead author of the study, said: "The results of this randomised trial suggest that nulliparas in spontaneous labour or with spontaneous rupture of membranes who request pain relief early in labour can receive spinal or epidural analgesia at that time without adverse consequences." She said current US guidelines that recommend delaying use of epidural analgesia should be changed. "If women think they may want an epidural at some stage, there is no point in delaying and using systemic opioids first. We can just go ahead with an epidural without increasing the risk of caesarean delivery."
However, she acknowledged several limitations to the study, including the fact that different obstetric providers and management styles (including patterns of oxytocin use) may have influenced labour outcomes. In addition, the study was not conducted blind. She considered it unlikely, however, that knowledge of the type of analgesia biased obstetricians?decisions about mode of delivery.(London Susan Mayor)