Introduction: Pregnancy is accompanied by progressive biomechanical and physiological adaptations that may impair postural balance and increase the risk of musculoskeletal disorders.

Objectives: This study aimed to investigate the effects of pregnancy on postural balance, medial longitudinal arch height, and lumbar lordosis in pregnant women.

Methods: In this cross-sectional study, 64 healthy pregnant women attending obstetrics and gynecology outpatient clinics were recruited and classified according to gestational trimester (first, second, and third). Demographic characteristics, parity, the Berg Balance Scale (BBS), the Y Balance Test (YBT), the Navicular Drop Test (NDT), and lumbar lordosis angle were assessed.

Results: No significant differences were observed among the trimester groups in age, height, weight, body mass index, or YBT performance (p > 0.017). Parity and gestational week differed significantly between groups (p < 0.017). Women in the third trimester demonstrated significantly greater navicular drop and lumbar lordosis angles, together with lower BBS scores, than those in the first and second trimesters (p < 0.017). Multiple linear regression analysis revealed that gestational week and parity were significant predictors of navicular drop (R² = 0.70, p < 0.001). To maintain an overall alpha level of 0.05 during multiple group comparisons, a Bonferroni correction was applied, setting the level of significance at p < 0.017.

Conclusion: Advancing pregnancy, particularly during the third trimester, is associated with impaired postural balance, increased navicular drops, and greater lumbar lordosis. These findings highlight the importance of routine assessment of balance and musculoskeletal adaptations during antenatal care to facilitate early identification of women at increased risk of functional impairment and to guide targeted preventive interventions.