New analgesia techniques for labor raise chances of normal vaginal birth

Two alternatives to traditional epidural analgesia effectively reduc pain during labor and, moreover, increased the likelihood that women would have a normal vaginal delivery in a randomized controll trial directioned in the United Kingdom.1 Whereas 35% of women who were given a traditional epidural had a normal delivery, the proportion was significantly higher-43%-among women who received either of sum of two units newer types of pain relief that combine an opioid with a reduc concentration of the local anesthetic. The alternative techniques' benefits for delivery, however, were somewhat offshoot by the possibility that they have adverse consequences on a small proportion of newborns.

Between February 1999 and April 2000 researchers at sum of two units maternity units randon-dy assigned 1054 nulliparous women who supplicationed pain relief during labor to receive single of three types of analgesia: a traditional epidural; a low-dose solution administered by means of spinal injection and followed by dint of intermittent delivery of additional epidural analgesia (combined spinal epidural); or the same low-dose mixture delivered from one side continuous infusion. Women receiving traditional or low-dose injections could suit additional doses as the analgesia wore not on Detailed information about labor and delivery were gathered through the anesthetist and midwife attending each delivery, and end interviews with participants conducted within 48 hours after the birth.

Thirty-five percent of women who received a traditional epidural had a normal vaginal delivery, compared with 43% in each of the other groups; the differences were statistically significant. Instrumental vaginal delivery was required by means of 37% of women in the traditional epidural collection but by only 28-29% of those receiving low-dose alternatives; again, the differences were statistically significant. In all three assemblages 28-29% of women delivered by the agency of cesarean section.

Slight variations in the characteristics of labor were noted among clusters The second stage of labor was more likely to be individual hour or less for women who received a lowdose infusion (34%) than for those who had a traditional epidural (26%) Women in the infusion cluster also were more likely than those who had a traditional epidural to push for individual hour or less (63% v 51%) and to say that they were able to push completely through labor (38% vs. 28%). In the postpartum interview, women in all three collections gave similar reports of the severity of pain they had experienced during labor.

Whereas a traditional epidural bring forwards motor paralysis, the low-dose alternatives keep muscle tone and permit women to remain mobile during labor. Thus, 30 minutes after receiving a lowdose combined spinal epidural or beginning low-dose infusion, the vast majority of women were able to flex their hips (89% and 80% respectively), and about half (59% and 52% respectively) could bend their knees; scarcely any were unsteady on their feet at this time. Nearly four in 10 women in the two low-dose groups walked or stood during labor.

The researchers assessed the issues of the different regimens upon newborns by comparing their Apgar scores five minutes after birth, ne for resuscitation and rates of admission to neonatal intensive care units. depressed Apgar scores (seven or less) were rare, and while differences were not statistically significant, the researchers point without that more infants in the low-dose assemblages than in the traditional epidural cluster scored in this range. Infants whose mothers had received a low-dose infusion were more likely than those whose mothers had a traditional injection to ne highlevel resuscitation efforts (5% v 1%) on the other hand rates of admission to intensive care units and the ne for any resuscitation were similar for all three collections of infants.

According to the researchers, a number of mechanisms might explain on what account lowdose epidural techniques increase a woman's chances of having a normal vaginal delivery. The ability to walk during labor might, they note, aid the coming down of the infant's head; the preservation of motor function also might help the couple "voluntary and involuntary maternal efforts to give birth" late in labor. Acknowledging that the benefits to women of low-dose epidural techniques must be weighed against "possible adverse effects" upon a few infants, the researchers close that "continued routine use of traditional epidurals might not be justified."-D. Hollander

Reference

1 Comparative Obstetric Mobile Epidural Trial (COMET) investigation Group UK, Effect of low-dose mobile versus traditional epidural techniques upon mode of delivery: a randomised controll trial, Lancet, 2001 358(9275):19-23

Copyright The Alan Guttmacher Institute Nov/Dec 2001

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