One of the most representative symptoms during childbirth is pain, which is one of the most prominent concerns of pregnant women. There are different instruments to assess pain, all of which require interrupting the woman, thus interfering with the intimacy of childbirth. This study seeks to develop and validate a rating scale of the expression of childbirth pain that does not require the mother's attention and respects her privacy during labor. The study was conducted at a regional hospital in a border town in southern Spain between November 2018 and September 2019. Scale items were developed following a review of the scientific literature, and experts judged the content validity. After a pilot test, the scale was psychometrically evaluated. The psychometric tests consisted of internal consistency analysis, exploratory factor analysis, and determination of the content, construct, and convergent validity. The scale was evaluated by 36 experts in the field and was then applied to 55 women during the active phase of childbirth. The final version of the Rating Scale of Pain Expression during Childbirth (in Spanish, Escala de Valoración de la Expresión del Dolor durante el Trabajo de Parto-ESVADOPA) consists of six items in two dimensions. The scale had a Cronbach's alpha coefficient of 0.78, and the content validity measured by Aiken's V co-efficient was also 0.78. The exploratory factor analysis yielded two dimensions that explained 68.08% of the total variance. For convergent validity, a comparison was made with the visual analogue scale, yielding a medium-high value of 0.641. As indicated by the internal consistency and by the content and construct validity outcomes, the ESVADOPA successfully measures pain expression during childbirth and represents a suitable tool for pain expression during birth without the need for intervention or the need for the mother to speak the same language as the midwife.
Keywords: childbirth; pain; parturient; psychometric test; scale; validation study.