During pregnancy, women often experience musculoskeletal pain, specifically in their low back and/or pelvic girdle. Pelvic girdle pain (PGP) is defined as pain between the posterior iliac crest and gluteal fold, particularly in the region of the sacroiliac joint (SIJ)1. Although it is often referred to as "sciatica". PGP in pregnancy is common with prevalence estimates of 45%2. Previous studies have found that one third of patients will rate their PGP intensity as severe, leading to functional impairments. Functional disabilities include sitting, walking, and standing; thus, significantly impacting the ability of patients to perform routine daily activities. This pain has been reported to develop as early as 17-19 weeks' gestation, lasting up to 3 months postpartum; with a peak incidence of 24-36 weeks.

The etiology of PGP in pregnant women is still not fully understood, largely due to the complex interactions between bone, ligaments, fascia, and muscles in the pelvic joints3. Some studies suggest the increased mobility of the joints in the pelvic girdle during pregnancy due to relaxing cause a lack of stabilization in the sacroiliac region, which results in pain4. Thus, it is hypothesized that providing stabilization of the joints with an external force, such as a maternity or SIJ belt, will improve pain.