Aim and background: Diastasis recti abdominis (DRA) is a disorder that can persist in 35–60% of women postpartum, leading to issues like core function issues, urine incontinence, and low back pain (LBP). Diastasis recti abdominis has been associated with modifications in spinal alignment, notably an elevation in lumbar curvature, potentially affecting the distribution of loads. Diastasis recti abdominis is a potential cause of postural abnormalities, and evaluating the relationship between them will be beneficial for the medical professionals to understand the need for abdominal muscle strengthening in the postpartum period and how it affects quality of life. Thus, this study aims to explore the relationship between postural changes and DRA in the postpartum phase. Materials and methods: This cross-sectional study design was conducted to find the relationship between spinal curvature and DRA using a bubble inclinometer, and a caliper respectively. A total of 102 patients underwent screening based on inclusion and exclusion criteria. An independent t-test and Karl Pearson's correlation method were used to find a comparison and relation of spinal curvature (thoracic kyphosis angle and lumbar lordosis angle) between with and without DRA groups, while a p-value < 0.05 was considered statistically significant. Results: The results of the present study stated that DRA was positively correlated (p < 0.05) with kyphosis angle (r = 0.322) and lordosis angle (r = 0.774). The findings of the current study also indicate a positive correlation between body mass index (BMI) and both DRA and the lordosis angle. Conclusion: This study revealed a strong positive correlation between DRA and lordosis angle and a weak positive correlation between DRA and kyphosis angle in postpartum women. Clinical significance: These findings emphasize the importance of holistic postpartum care to address musculoskeletal changes, providing insights for interventions to improve core muscle function and alleviate chronic spinal pain.