Pelvic alignment risk factors associated with sacroiliac joint pain during pregnancy

Purpose of investigation: To investigate the influence of the change in pelvic alignment during pregnancy on sacroiliac joint pain (SIJP). Materials and Methods: Participants included 168 women without SIJP at recruitment and were evaluated at 12 and 36 weeks of pregnancy. SIJP intensity was assessed using the Numerical Rating Scale (NRS). Pelvic alignment measurements included the anterior and posterior width of the pelvis, anterior pelvic tilt, and pelvic asymmetry. Participants were divided into the SIJP and non-SIJP groups based on the presence of SIJP at 36 weeks of pregnancy. The influence of the change in pelvic alignment during pregnancy between the groups was investigated. Results: The amount of change in pelvic anteversion during pregnancy was smaller and the change in pelvic asymmetry was significantly greater in the SIJP group compared to that in the non-SIJP group. In addition, an increase in pelvic asymmetry was the most strongly associated risk factor for SIJP. Conclusions: A forward-bending pelvis in early pregnancy and an increase in pelvic asymmetry during pregnancy are risk factors for pregnancy-related SIJP.