Reliability and validity of the Acceptance Symptom Assessment Scale in assessing labour pain

Objective: to investigate the reliability and validity of the Acceptance Symptom Assessment Scale (ASAS) in assessing labour pain. Design: a test-retest approach was used to assess reliability and validity. Setting: labour ward with approximately 2,400 deliveries annually in western part of Sweden. Participants: forty-seven pregnant women in the latent or active phase of labour. Methods: a total of five pain assessments with both the ASAS and the VAS were conducted in three sessions. Main outcome measures: correlation between ASAS and VAS. Findings: both scales demonstrated high and significant test-retest correlations (r=0.83-0.92; p<0.001). High and significant alternative-form reliability correlations (r=0.76-0.93, p<0.001) were found between ASAS and VAS ratings at all five assessments. Construct validity was established when both the ASAS and the VAS identified a pain reduction (p<0.001) 2 hrs after birth, compared to the previous assessment. Over two-thirds of the women preferred the ASAS to the VAS, mainly (n=30) because the ASAS provided more choices relating to the pain experience, making it possible to label pain acceptable/unacceptable. Conclusions: the ASAS is interchangeable with the VAS for assessing labour pain. Over two-thirds of the women preferred it to the VAS. (C) 2011 Elsevier Ltd. All rights reserved.