Tools for assessing labour pain: a comprehensive review of research literature.

The experience of pain associated with labour is complex and challenging to assess. A range of pain measurement tools are reported in the literature. This review aimed to identify current tools used in research to assess labour pain across the past decade and to evaluate their implementation and adequacy when used in the context of labour pain. A literature search was conducted in databases MEDLINE and Cumulative Index of Nursing and Allied Health Literature, using search terms relating to labour, pain, and measurement. A total of 363 articles were selected for inclusion. Most studies (89.9%) assessed pain as a unidimensional experience, with the most common tool being the Visual Analogue Scale, followed by the Numerical Rating Scale. Where studies assessed pain as a multidimensional experience, the most common measurement tool was the McGill Pain Questionnaire. Only 4 studies that used multidimensional tools selected a tool that was capable of capturing positive affective states. Numerous variations in the implementation of scales were noted. This included 35 variations found in the wording of the upper and lower anchors of the Visual Analogue Scale, some assessment tools not allowing an option for "no pain," and instances where only sections of validated tools were used. It is clear that development of a standardised pain assessment strategy, which evaluates the multidimensions of labour pain efficiently and effectively and allows for both positive and negative experiences of pain to be reported, is needed.