[Relationship between pregnant women's sensitivity to cold (hiesho) and premature labor assessed using propensity scores for adjusting confounding factors].

The purpose of this study is to analyze the influence of sensitivity to cold or hiesho in pregnant Japanese women and to examine the relationship between hiesho and premature labor. In this retrospective cohort study in Japanese women after delivery, information for the approximately 12 months between October 19, 2009 and October 8, 2010 was obtained using questionnaire surveys and medical records at 6 hospitals with obstetric and pediatric departments in the Greater Tokyo Metropolitan Area. Further, in this analysis, confounding factors were adjusted by performing analysis of covariance and stratified analysis using propensity scores. The Research Ethics Review Committee of St. Luke's College of Nursing (09-057) approved this study. Analysis of data from 2,810 women was performed. Regarding the correlation between hiesho and premature labor, the incidence of premature labor was 3.38 times higher (analysis of covariance) or 3.47 times higher (stratified analysis) among pregnant women with hiesho than among those without hiesho (P < 0.001). The results of this study proved the existing discussions that there is a correlation between hiesho during the latter stages of pregnancy and incidence of premature labor.