A review calls for more trials on techniques that have only empirical support.
Although there are numerous popular approaches—both pharmacologic and nonpharmacologic—to managing pain during labor and childbirth, a recent major examination of reviews on the efficacy and safety of these interventions found little evidence that nonpharmacologic approaches are effective. What isn't clear is whether these findings are indicative of a failure of the approaches themselves or of the existing studies.
In an attempt to provide a single, accessible summary of the available evidence for clinicians, educators, and consumers, Jones and colleagues looked at 15 Cochrane reviews (a total of 257 trials) and three non-Cochrane reviews (55 trials), dividing their findings into three categories: “what works,” “what may work,” and “insufficient evidence to make a judgment.”
The first category, methods proven to work, included epidural injections; combined spinal epidurals (injection of an anesthetic or opiate into the cerebral spinal fluid plus an epidural catheter for faster pain relief); and an inhaled analgesic, such as nitrous oxide. Although there's strong evidence that these approaches are effective in managing pain, all are associated with adverse effects—such as increases in the risks of instrument-assisted vaginal birth and cesarian section for fetal distress with epidural use, and vomiting, dizziness, and drowsiness with inhaled analgesia.
The second category, methods that may work, included immersion in water, relaxation, acupuncture, massage, local anesthetic nerve block (injection of anesthetic around the pudendal nerve or the cervix), and nonopioid drugs, such as sedatives, nonsteroidal antiinflammatory drugs, and antihistamines. The authors found some evidence to suggest that these methods can assist in managing pain with relatively few adverse effects. In most cases, women did report satisfaction with pain relief, but evidence was mainly limited to individual trials.
Methods that fell into the third category (insufficient evidence to make a judgment) were hypnosis, biofeedback, sterile water injection (small quantities of water injected in the skin over the sacrum), aromatherapy, transcutaneous electrical nerve stimulation (TENS), and the use of parenteral opioids such as morphine. These interventions are, for the most part, noninvasive and are apparently safe for mother and baby, but their effectiveness is unclear because there is too little high-quality evidence.
Despite the lack of statistical evidence, however, experts within the nursing community see reasons every day to support the use of nonpharmacologic techniques. “It's clear that further research is needed to help women make better-informed decisions, but from a practical point of view, we already know that these techniques are benefiting women,” said Eileen Ehudin Beard, senior practice advisor for the American College of Nurse-Midwives.
“Nonpharmacologic pain management strategies preserve freedom of movement, reduce the need for drugs associated with adverse effects, improve women's satisfaction with pain relief, and help patients feel more in control through the birth process.”
The authors of the Cochrane review would likely agree. They call for further trials of nonpharmacologic pain management methods, particularly those like TENS, which are popular with women and midwives but lack definitive trials. They also note that “it remains important to tailor methods used to an individual woman's wishes, needs and individual circumstances.”—Laura Wallis
Jones L, et al. Cochrane Database Syst Rev. 2012(3):CD009234