Introduction  The demographic composition of the ethnic Korean population in Japan (often referred to as zainichi) shows a declining birthrate. However, zainichi who live in zainichi Korean communities have more children than zainichi living in predominantly Japanese communities. Social capital (SC) can increase societal efficiency by promoting cooperative behavior within communities. This study clarified the family formation and SC that supports childcare for zainichi mothers living in zainichi Korean communities.Methods  We conducted semi-structured interviews with 10 zainichi mothers living in zainichi Korean communities in Japan. We qualitatively and descriptively analyzed the family formation and SC that support childcare in this population. The Ethical Committee of Osaka Prefecture University approved this study and the participants gave their written informed consent.Results  We extracted three categories and 12 subcategories for “thoughts on current family formation” and four categories and 11 subcategories for “SC supporting childcare.” Zainichi mothers living in Korean communities “think consciously about marriage” and “think positively about having multiple children and family formation,” but they have “concerns about childbearing and child-rearing.” “People who support childcare practically and mentally” and “childcare services” were also identified as important factors. Although zainichi mothers felt dissatisfied with “support that they wanted to use but found difficult to use,” they considered childcare support as human and physical SC. As an additional resource, they felt that “the zainichi community fosters security and bonding,” and thus promotes SC for child-rearing.Discussion  Networks with common norms, values, and understanding facilitated cooperation among zainichi mothers. “The zainichi community, which fosters security and bonding,” may support family formation through engendering a positive perception of child-rearing.

Objectives  High gestational weight gain (GWG) is associated with perinatal risks to mother and child. Research shows that non-Japanese Asian women have higher GWG than Japanese women. However, no studies have compared GWG in these two populations using GWG recommendations in accordance with Japanese and Institute of Medicine (IOM) guidelines. The study aim was to compare GWG in non-Japanese Asian and Japanese pregnant women.Methods  This was a retrospective observational study. All participants were aged ≥20 years and gave birth between September 2019 and the end of October 2020 at one perinatal medical center in Japan. Medical record data were analyzed for 170 non-Japanese Asian and 316 Japanese pregnant women. We used t-tests and chi-square tests to examine differences in age, parity, smoking status, antenatal checkups, pre-pregnancy body mass index, and GWG. Logistic regression analysis was used to estimate odds ratios (95% confidence intervals) for above- and below-recommended GWG by non-Japanese Asian and Japanese status. We also analyzed differences in delivery type, abnormal blood loss, and birth size according to GWG.Results  After adjustment for confounding factors, the multivariable-adjusted OR and 95% CI for GWG above the Japanese guidelines recommendations was 1.86 (1.23-2.81) and that for GWG above IOM guidelines recommendations was 2.46 (1.45-4.16) for non-Japanese Asian women, as compared with Japanese women. Conversely, the multivariable-adjusted OR and 95% CI for GWG below Japanese guidelines recommendations was 1.55 (1.03-2.32) and that for GWG below IOM guidelines recommendations was 1.87 (1.26-2.76) for Japanese women, compared with non-Japanese Asian women. Conclusion  Because Japanese women tend to be below recommended GWG and non-Japanese Asian women tend to be above recommended GWG, midwives need to provide careful guidance to reduce perinatal risks.