Update on Nonpharmacologic Approaches to Relieve Labor Pain and Prevent Suffering

Penny Simkin, PT; April Bolding, PT


J Midwifery Womens Health. 2004;49(6) 

In This Article

Intradermal Water Blocks

Intradermal water blocks, also called intracutaneous sterile water injections, decrease low back pain during labor.[10] Estimates of the incidence of low back pain in labor range between 15% and 74% of all labors.[29] Possible etiologies of low back pain in labor include a fetal occiput posterior position, persistent asynclitism, the woman's individual lumbopelvic characteristics, and referred pain from the uterus. Because the corpus uteri and cervix are supplied by afferent neurons ending in the dorsal horn of spinal segments T10-L1 and cutaneous afferents from the low back converge in the same segments, there is anatomical support that low back pain in labor is actually referred pain.[30]

Intradermal water blocks consist of 4 intradermal injections of 0.05- to 0.1-mL sterile water (using a 1-mL syringe with a 25-gauge needle) to form 4 small blebs, 1 over each posterior superior iliac spine and 2 others placed 3 cm below and 1 cm medial to each of the first sites. Exact locations of these do not appear to be critical to its success[31] (Figure 1).

Figure 1.

Placement for injections of intradermal water blocks.

The injections sting acutely for 20-30 seconds, but as the stinging fades, the back pain fades. Using saline injections instead of sterile water causes less initial intense stinging and is less effective in decreasing low back pain.[32,33] To offset the discomfort of administration, some providers give injections during a contraction and have 2 providers give 2 injections simultaneously to speed the process. The water blocks can be repeated as desired.[31]

Effectiveness of Intradermal Water Blocks in Decreasing Labor Pain and Suffering

All of the 4 published RCTs compared low back pain in an experimental group who received intradermal water blocks and a control group who received either a "placebo" blank (using saline)[30,32,33] or an alternative nonpharmacologic method (TENS, movement, massage, and baths).[29] The findings are summarized in Table 4 . All 4 studies found that the intradermal water blocks were effective in decreasing severe low back pain in most laboring women within minutes. Pain relief lasted 45 to 120 minutes, and most women stated they would want to use intradermal water blocks again during a subsequent birth.[30,32,33] In the 3 studies that investigated requests for other pain medication,[29,32,33] there was no decrease in the requests in the group of women treated with intradermal water blocks, despite the pain relief provided by them. Possible explanations for this finding are that the block decreased only low back pain (not abdominal labor pain) and that pain relief only lasted up to 120 minutes, after which the water blocks were not repeated. One study[29] compared the efficacy of 3 different treatments to decrease low back pain: intradermal water blocks, TENS, and "usual care," including massage, ad lib baths, and movement. Even though the water blocks were effective in decreasing low back pain, more in the usual care group wanted to repeat the treatment they received and had the lowest requests for pain medication. The largest trial,[33] which was well designed and had low risk of bias, found that the number of cesarean deliveries was significantly lower in the group who received the intradermal water blocks.

In summary, 4 RCTs have found that intradermal water blocks reduce severe low back pain in most laboring women without any identified side effects on the fetus or mother, except for the transient, though extreme pain, with administration. It is a simple and inexpensive way to provide a medication-free option to women who want to either avoid or delay use of epidural analgesia or for those for whom epidurals are not available.[10] Further research is needed on the effects of intradermal water blocks on obstetric outcomes, the effects of repeated injections, ways to decrease the stinging of the injections without losing benefits, its mode of action, and the effects of varying dosages, locations, and number of sites injected.


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