The Validity and Reliability of a Scale on Postnatal Posttraumatic Stress Symptoms Related to Childbirth among Japanese Women: Evaluation of the Japanese-language Version of the Impact of Event Scale-revised

Abstract

Objective: The aim of this study was to examine the validity and reliability of the Postnatal Women Version of Japanese-language version of the Impact of Event Scale-Revised (IES-R-J-PWV) at one month after childbirth among Japanese women.Methods: Data were collected at two general hospital maternity wards and one obstetric clinic in Aichi Prefecture from July to December 2013. A total of 260 postnatal Japanese women participated in this study. The women completed anonymous self-report questionnaires at one month postpartum. To examine the construct validity of the IES-R-J-PWV, we conducted exploratory factor analysis with promax rotation. We evaluated the criterion-related validity of the IES-R-J-PWV using Spearman's correlation coefficients between IES-R-J scores and scale scores from the Japanese Edinburgh Postpartum Depression Scale (JEPDS), the Visual Analog Scale (VAS), and the Sense of Coherence-13 (SOC-13) instrument.Results: Exploratory factor analysis revealed that the IES-R-J-PWV was composed of four factors. The total subscale scores for the four factors significantly correlated with each subscale score. The IES-R-J-PWV was positively correlated with the JEPDS (rs = 0.40, p < 0.01) and the VAS (rs = 0.47, p < 0.01) and negatively correlated with the SOC-13 (rs = -0.33, p < 0.01). The IES-R-J-PWV had good internal consistency, with a Cronbach's α coefficient of 0.92. Conclusions:The results of this study indicated that the IES-R-J-PWV was a valid and acceptable instrument for measuring and evaluating postnatal posttraumatic stress symptoms related to childbirth among Japanese women at one month after childbirth.