Background Studies on disease activity of ankylosing spondylitis in pregnancy have shown diverging results. A large retrospective study from 1998 without validated disease activity scores found no particular pattern of disease course during pregnancy (1). Later two small studies demonstrated a tendency towards lower disease activity in the beginning of pregnancy and deterioration in late pregnancy (2,3). None of these studies included women with non-radiographic axial spondyloarthritis. The only large study was conducted before the widespread use of biological DMARDs.
Objectives The aim of this project was to prospectively study disease activity in women with axial spondyloarthritis before, during and after pregnancy with BASDAI as disease activity measure.
Methods RevNatus is a Norwegian nationwide register designed for the follow-up of pregnant women with rheumatic diseases. RevNatus included 181 full term pregnancies in 168 women with axial spondyloarthritis between 2006 and 2016. The women had seven visits at a rheumatology unit; before pregnancy, in each trimester, and six weeks, six months and twelve months postpartum. BASDAI-values from each visit were analyzed in a linear mixed model.
Results Even though we found a statistically significant relationship between disease activity and time point in the follow-up period, our study demonstrated that women with axial spondyloarthritis had stable, low disease activity during and after pregnancy. Disease activity in second trimester was significantly higher than six weeks after delivery, but the change in estimated mean BASDAI was small (BASDAI 3.97 vs. BASDAI 3.46, p=0.005). The figure below shows changes in disease activity throughout the study period.
Conclusions Studying women with axial spondyloarthritis, we found that disease activity was highest in second trimester, but altogether stable in the period from planning pregnancy to one year after delivery.
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Disclosure of Interest None declared