MRI lesions predict axial spondyloarthritis in pregnant and postpartum women

The key findings of this study were:

BME was prevalent throughout pregnancy and the postpartum period, culminating at 3 months postpartum with an incidence of 69% (SPARCC)/80% (two-plane), although it was remained prevalent at 12 months postpartum in 54% (SPARCC)/58% (two-plane). 

At 12 months postpartum, 41% of women met the criteria for sacroiliitis according to the current ASAS definition, whereas 21%/14% of women matched the criteria for active/structural SIJ lesions according to the newly suggested ASAS MRI thresholds. 

At all timepoints, BME tended to concentrate in the anterior middle joint parts, and ligamentous BME was uncommon. 

Just 2.8% of women had SPARCC erosion scores below 3 (ASAS threshold) at 12 months postpartum.

In conclusion, it may be possible to distinguish between postpartum strain-related disorders and axSpA-related sacroiliitis using the topographical BME distribution and almost no erosions (ASAS threshold) at 12 months after delivery.

Reference:

Kiil, R. M., Weber, U., Loft, A. G., Maimburg, R. D., & Jurik, A. G. (2023). Evolution of MRI lesions at the sacroiliac joints during and after pregnancy by serial MRI from gestational week 20 to 12 months postpartum. In Arthritis & Rheumatology. Wiley. https://doi.org/10.1002/art.42457