Social isolation and insomnia among pregnant women in Japan: The Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

Objectives: To estimate the prevalence of insomnia and examine the association between social isolation and insomnia among pregnant women. Methods: This cross-sectional study was part of the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study from 2013 to 2017. Pregnant women were recruited at obstetric clinics and hospitals in Miyagi Prefecture, Japan. We analyzed 17,586 women who completed the questionnaires and were allowed to transcribe medical records. Insomnia was defined as the Athens Insomnia Scale score of ≥6. The Lubben Social Network Scale-abbreviated version was used to assess social isolation (defined as scores <12), and its subscales were used to assess marginal family ties and marginal friendship ties. Multiple logistic regression analyses were conducted to examine the association between social isolation and insomnia during pregnancy, adjusting for age, parity, prepregnancy body mass index, feelings toward pregnancy, education, income, work status, morning sickness, and psychological distress. Multiple logistic regression analyses were also conducted for marginal family ties and marginal friendship ties. Results: The prevalence of insomnia in the second trimester was 37.3%. Women who were socially isolated were more likely to have insomnia than women who were socially integrated: the multivariate-adjusted odds ratio (OR) was 1.26 (95% confidence interval [CI], 1.16-1.36). Marginal family ties and marginal friendship ties were also associated with increased risks of insomnia: the multivariate-adjusted ORs were 1.40 (95% CI, 1.25-1.56) and 1.15 (95% CI, 1.07-1.24), respectively. Conclusions: Social isolation from family and friends was associated with increased risks of insomnia among pregnant women.