Labor pain assessment: validity of a behavioral index

There is a need for adequate and convenient measures for assessing obstetric pain. The present investigation was designed to develop a non-verbal objective measurement of labor pain based on the continuous observation of behavior. Validity and sensitivity of the instrument designed to assess pain throughout labor using standardized observational ratings were tested on a sample of 100 primiparae who were asked periodically to rate pain on a 5-point numerical scale. The use of a behavioral method of observation associated with a self-rating procedure comprises various advantages, especially because they may appreciate different factors of the pain experience. Behavioral and self-rating indices were satisfactorily correlated. The behavioral index correlates with the pre-partum anxiety score but the self-rating index does not. The positive results obtained in this preliminary study lead us to consider this behavioral index as a valid instrument.