New Ways to Talk about Labor Pain V: Research on Effectiveness of 3 Mechanisms

In 2012, a new Cochrane review of pain management for women in labor was released. Although it had positive things to say about the non-pharmacological techniques, it also said that research into their efficacy was unclear due to limited evidence…

“WHAT WORKS: Evidence suggests that epidural, combined spinal epidural (CSE) and inhaled analgesia effectively manage pain in labour, but may give rise to adverse effects. … WHAT MAY WORK: There is some evidence to suggest that immersion in water, relaxation, acupuncture, massage and local anaesthetic nerve blocks or non-opioid drugs may improve management of labour pain, with few adverse effects.  Evidence was mainly limited to single trials. …INSUFFICIENT EVIDENCE: There is insufficient evidence to make judgements on whether or not hypnosis, biofeedback, sterile water injection, aromatherapy, TENS, or parenteral opioids are more effective than placebo… Most methods of non-pharmacological pain management are non-invasive and appear to be safe for mother and baby, however, their efficacy is unclear, due to limited high quality evidence.”

A 2014 review by Chaillet, et al (Chaillet, et al. (2014) Nonpharmacologic approaches for pain management during labor compared with usual care: a meta-analysis. Birth, 41(2): 122-37. http://www.ncbi.nlm.nih.gov/pubmed/24761801) is a significant addition to the research about non-drug approaches.

Chaillet, et al pooled techniques into three categories. If you’ve read my posts from the past few days, you’ll be familiar with these concepts. Also, see the chart at the top of this post for more information.

• Gate Control mechanism = apply non-painful stimuli on the painful area. Methods included massage, bath, positions, walking, and birth ball. The theory is that this will block some of the intensity of the pain.
• Diffuse Noxious Inhibitory Control (counter-irritant) = create pain or discomfort anywhere on the body. Methods included acupressure, acupuncture, TENS, sterile water injections. The theory is that this discomfort causes the body to release endorphins which reduce pain intensity. (Birth combs also fit in this category although they were not included in the research.)
• Central Nervous System Control (cognitive/support techniques). Methods included  attention focus, education, relaxation, hypnosis, continuous labor support.

By pooling studies together, you get larger sample sizes which increases the statistical significance of the results. Note, all techniques were compared to “usual care” which might have ranged broadly depending on the preparation of the laboring family and the support they were given by caregivers. It is possible that some in the “usual care” groups were also using a variety of coping techniques. So, the true difference between people who use some coping techniques and those who use none may be even greater than these results indicate.

The results of this review were:

• Gate Control mechanism. Those who used these techniques had lower pain intensity (as predicted), were less likely to use epidural, and needed less Pitocin.
• Diffuse Noxious Inhibitory Control (counter-irritant). Those who used these techniques had lower pain intensity, were less likely to use epidural, and more satisfied with birth. (Two trials found women felt safer, more relaxed, and more in control.)
• Central Nervous System Control (cognitive/support techniques) Those who used these techniques were less likely to use epidural, Pitocin, less likely to need instrumental delivery or cesarean, and had a higher satisfaction with birth. The CNSC did not reduce the intensity of the pain so much as they reduced the unpleasantness of the pain. (See more on intensity and unpleasantness here.) So, although labor still hurt a lot, women felt better able to cope – more like they were working with labor pain.

The most effective technique overall was continuous labor support, such as that offered by a doula. The effectiveness of support was already demonstrated in a Cochrane review by Hodnett et al, (Hodnett E, Gates S, et al.. Continuous support for women during in childbirth. Cochrane Database Syst Rev. 2013. CD003766)

The best results in pain coping were from combining the labor support and education which reduce the unpleasantness of pain with gate control or DNIC techniques that reduce the intensity of the pain.

Recommended: be sure to also check out Henci Goer’s discussion of this study on Science and Sensibility.

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