Patterns and prevalence of sacroiliac joint bone marrow edema during pregnancy: A retrospective analysis.

Introduction: Pregnancy is associated with the presence of bone marrow edema (BME) in the sacroiliac joints during the postpartum period. The aim of this study is to evaluate the frequency and localization of sacroiliac joint edema during pregnancy.

Methods: This retrospective, monocentric study included pregnant women who underwent pelvic MRI for any reason during their pregnancy. Women with a history of chronic inflammatory rheumatic diseases and minors were excluded. Two experienced readers independently evaluated the presence of bone marrow edema (BME) using a two-plane assessment method: axial and semi-coronal oblique views. Each sacroiliac joint was divided into four quadrants per slice and the presence of deep lesion was also scored.

Results: We included 28 women with a median age of 30.0 [27.0-33.0] years and a median gestational age of 27.5 [25.5-32.0] weeks of amenorrhea. Ten women (36%) presented with at least one BME in a sacroiliac joint, and 3 of these women had bilateral sacroiliac joint BME. BME was observed in 12 of 13 cases (92%) in the lower part of the sacroiliac joint. In 8 cases (66%), the edema was present on both the iliac and sacral sides, in 1 case (8%) only on the iliac side, and in 4 cases (33%) only on the sacral side. There were no correlation between gestational age and the presence of BME.

Conclusion: BME in the sacroiliac joint is common during pregnancy and is typically located in the anterior and inferior parts of the joint, similar to the postpartum period.