NEW ORLEANS – Laboring women had better overall pain relief satisfaction from epidurals than from remifentanil patient-controlled analgesia, according to results presented at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine.
Although Dr. Liv Freeman, of Leiden (the Netherlands) University Medical Center, and her colleagues expected to find that the two pain relief methods would be equivalent, the results of their multisite, randomized controlled study instead showed a significantly higher pain appreciation (pain relief satisfaction) score in women who received epidural analgesia during delivery.
Dr. Liv Freeman
"This should be taken into account when pain relief is offered to women in labor," said Dr. Freeman, who noted that the study’s intention was to provide more definitive data about the two pain relief methods because previous studies were underpowered – with some data showing the two methods were comparable.
An advantage to using remifentanil, an opioid similar to pethidine, is that it is fast-acting, typically cycling within 3 minutes. This attribute allows the drug to be self-administered and lowers costs, said Dr. Freeman. There are maternal side effects, however, including respiratory depression, nausea and vomiting, and sedation.
Placental transfer also occurs with remifentanil, although "the drug is so short acting, it is cleared once the baby is born when discontinued in the second stage of labor," Dr. Freeman said.
As for the potential risks of using an epidural, Dr. Freeman said that although rare, epidural hematomas can occur, and that "about 1 in 100 women experience postspinal headache, and between 10% and 20% of mothers develop a fever during labor."
Before active labor began, 709 women were randomly assigned to the remifentanil patient-controlled analgesia (PCA) group, and 705 were assigned to the epidural group. The maternal age was about 31 years in each group, and other demographic baseline data also were similar. Nearly one-third more of the remifentanil PCA group, 402 women in all, opted to use the pain medication during labor, and 296 assigned to the epidural group chose to use it.
All women across the cohorts were asked hourly to rate their pain relief on a visual analog scale.
The total time-weighted pain appreciation score for the remifentanil PCA group was 25.7, versus 36.8 in the epidural group (P = .001).
Although the analysis was based on intention to treat, Dr. Freeman noted that 53 of the women in the self-administered pain relief group requested epidurals while in labor. Three women converted from an epidural to the self-administered pain medication.
The epidurals were performed according to local procedures across the 15 Dutch sites where the trial was conducted. Remifentanil PCA was 30 mcg administered intravenously with a 3-minute lockout time. The women had the option of increasing their dose to 40 mcg or decreasing it to 20 mcg.
The duration of analgesia was notably shorter in the remifentanil PCA group than in the epidural group: 236 minutes (interquartile range, 128-376 minutes) vs. 309 minutes (IQR, 181-454 minutes).
There were 22 elective cesarean deliveries in the remifentanil group and 29 in the epidural group. Three women in the epidural cohort were lost to follow-up, and two withdrew their consent.
There were no significant differences in important maternal and fetal outcomes, said Dr. Freeman. Because the safety profiles of remifentanil and epidural analgesia are essentially the same, physicians should counsel women about the pros and cons of each, she said.
This study was funded by ZonMw, the Netherlands Organisation for Health Research and Development. Dr. Freeman did not report any relevant financial disclosures.