Introduction: It is important to elucidate the psychologically positive aspects of childbirth for mothers, and not only the negative aspects such as perinatal depression. This study aimed to examine psychological growth after childbirth and its related variables by focussing on five factors of posttraumatic growth: relating to others, new possibilities, personal strength, spiritual change and appreciation of life.Methods: Pregnant women during mid-pregnancy were consecutively recruited at a women's hospital in Japan and followed up 1 month after childbirth. Psychological growth was assessed by the Posttraumatic Growth Inventory.Results: Among 177 participants, 117 (66.1%) completed follow-up assessments 1 month after childbirth. Multivariable regression analysis revealed that primipara, higher resilience and less fear at childbirth were associated with posttraumatic growth factors of relating to others and new possibilities. High resilience and less fear at childbirth were also associated with personal strength. On the other hand, being primiparous and high depressive symptoms were associated with greater appreciation of life. No variables were associated with spiritual change.Discussion: These findings suggest that giving birth for the first time could be a highly challenging life event as well as an opportunity which leads to PTG, and that giving birth with low fear might lead to mothers' psychological growth. On the other hand, appreciation of life might need attention as it might signify some sorts of coping response. These findings contribute to our understanding of the psychological changes experienced by mothers.