Identifying procedural components for analogue research of labor pain.

The purpose of this study was to identify procedural components to be used in analogue studies of preparatory techniques for childbirth. The questions asked were (a) which of four laboratory pain stimuli (modified submaximum effort tourniquet technique. Forgione-Barber pain stimulator, cold water stimulus, faradic shock) is most similar to the pain associated with the transition phase of labor? and (b) what is the patterning and duration of contractions and intercontraction intervals in this phase? Forty primiparous women rated their contractions (within 48 hours following delivery) and rated the four laboratory stimuli (six to eight weeks postpartum) using the McGill Pain Questionnaire. Significant correlational relationships were found between each laboratory stimulus and contraction ratings. Uterine monitor records were scored to obtain contraction and intercontraction data: mean number and duration of contractions, mean duration of intercontraction intervals. The general patterning of these variables was relatively stable. In a subsequent laboratory trial using the above parameters, the Forgione-Barber pain stimulator was found to be the stimulus of choice.