Let me start by giving a link to some basic information (effects, how administered, advantages, drawbacks) on the Childbirth Connection website page on sterile water injections. However, you asked for the research. I haven't looked this up since I researched it for my book, The Thinking Woman's Guide to a Better Birth. I have two references there:

Ader L, Hansson B, and Wallin G.  Parturition pain treated by intracutaneous injections of sterile water. Pain 1990;41:133-8.

Trolle B et al. The effect of sterile water blocks on low back labor pain. Am J Obstet Gynecol 1991;164(5):1277-81.

I went to PubMed, looked up Trolle (1991) and clicked the "related articles" link to get this list of studies. You can go through them and see what is useful to you.

-- Henci

Hi.  I work as a L&D RN and am trying to get my hospital to offer sterile water injections.  Can you refer me to any research to present to management/MDs on pathophysiology of why it works and efficacy?  Thanks!