AIMS: To explore the association between body image, fear of childbirth and maternal-fetal attachment and the mediating effects of fear of childbirth among different body image profiles. DESIGN: A cross-sectional study. METHODS: Pregnant women were recruited from obstetric outpatient clinics between February 2022 and October 2023. Face-to-face data were collected using validated questionnaires. First, the mediating role of fear of birth was examined between body image and maternal-fetal attachment by calculating the total scores. Then, latent analysis was performed to identify body image profiles, and the relative mediation effects were examined for fear of childbirth in the association between body image profiles and maternal-fetal attachment. RESULTS: This study included 676 pregnant women, most of whom were in their third trimester. Using the total score, fear of childbirth was found to partially mediate the relationship between body image and maternal-fetal attachment. Latent profile analysis revealed three body image profiles in pregnant women: positive, moderate and negative. Using positive body image as the reference, pregnant women with moderate body image experienced a higher fear of childbirth, resulting in lower maternal-fetal attachment. Notably, the relative mediating effect of fear of childbirth was more pronounced in women with more negative body image profiles. CONCLUSION: Body image affected maternal-fetal attachment directly and indirectly through fear of childbirth, with stronger mediating effects among women with more negative body image profiles. IMPLICATIONS: The findings provide evidence on the underlying pathways between body image and maternal-fetal attachment and suggest body image and fear of childbirth as potential intervention targets to improve maternal-fetal attachment. Pregnant women with more negative body image may benefit more from such interventions. IMPACT: Little is known about the pathway between body image and maternal-fetal attachment in pregnant women. Body image affects maternal-fetal attachment directly and indirectly through fear of childbirth. The mediating effects of fear of childbirth were more pronounced among women with more negative body image profiles. These findings highlight fear of childbirth in the association between body image and maternal-fetal attachment and identify women with a more negative body image as high-risk populations, which provides insights for developing personalised interventions to improve perinatal psychological health. REPORTING METHOD: The study has followed the STROBE checklist for reporting method. PATIENT OR PUBLIC CONTRIBUTION: No patient or public contribution.