[Effectiveness of an educational video about infant crying on prevention of shaken baby syndrome among pregnant Japanese women and their partners].

Objectives　Previous studies have shown that educating new mothers or pregnant women about infant crying, may prevent shaken baby syndrome (SBS). However, no studies in Japan have examined the effectiveness of educational materials during pregnancy. This study aims to determine whether pregnant women and their partners improve their knowledge about infant crying and SBS, after watching an educational video created by the Ministry of Health, Labour, and Welfare.Methods　The study was conducted from April 1, 2013, to March 31, 2014, in 46 municipalities nationwide. Pregnant women and their partners, who participated in prenatal classes, watched the educational video and responded to pre- and post-questionnaires that included questions about: the characteristics of parents and family, and knowledge about infant crying and SBS. Out of the 4769 respondents who completed the questionnaires, responses of 4647 respondents with knowledge about infant crying and SBS were analyzed. We asked six questions about infant crying, such as "When an infant cries it is always a sign that something is wrong", and two questions about SBS, such as "Shaking a baby is a good way to help a baby stop crying" using a 4-point Likert scale (0-3 points). The total scores were calculated and placed within the range of 0 to 100, where higher scores indicated better knowledge. These scores were then compared for the pre- and post-conditions. Furthermore, a stratified analysis was performed based on respondents' characteristics and a regression analysis was conducted to examine the differences in knowledge categorized by these characteristics.Results　The scores displayed a significant increase in knowledge about infant crying and SBS by 17.5 points (95% CI; 17.1-17.9) and 6.8 points (95% CI; 6.3-7.2) respectively, after watching the educational video. The results of the stratified analysis found that the effect of the intervention did not differ depending on characteristics such as age, sex, education, and prevalence of depression. Furthermore, our regression analysis on the scores of knowledge about infant crying and SBS found that the increases in knowledge were more pronounced among males and couples having their first child. Increase in knowledge about infant crying was more pronounced among those who were not depressed, while increase in knowledge about SBS was more pronounced among those who answered "unexpected but happy" for their feelings about pregnancy.Conclusion　The educational video on infant crying and shaken baby syndrome was effective in increasing knowledge about infant crying and SBS among couples during pregnancy, regardless of their characteristics.