 This study found that lack of social support and trust during pregnancy and a 2.5 years postpartum had a negative impact on mothers' mental and physical health. Specifically, lack of close friends slash neighbors, Q4, at only 2.5 years postpartum, effect estimate, minus 6.23, and lack of emotional support, Q2, at the same time point, effect estimate, minus 4.94, had the greatest negative effects on mothers' mental health. Lack of social support and trust also carried higher risks for mothers' mental health if it occurred at only 2.5 years postpartum compared to both time points. This suggests that providing support for mothers beyond the first year after giving birth may be important for maintaining good mental health. This article was authored by Kenta Matsumura, Yoko Morizumi, Kei Hamazaki, and others.