Disease Activity of Juvenile Idiopathic Arthritis during and after Pregnancy: A Prospective Multicenter Study

Objective To study disease activity in women with juvenile idiopathic arthritis (JIA) during and after pregnancy. There is little previous knowledge about this topic.

Methods Our study included 135 pregnancies in 114 women with JIA. Disease activity was assessed at 7 timepoints before, throughout, and after pregnancy with the Disease Activity Score–28–C-reactive protein 3 (DAS28-CRP3). Scores assessed at each visit were analyzed in a linear mixed model. The same statistical method was used to study self-reported physical function, pain, and mental health.

Results Almost 80% of the women were in remission or had low disease activity during and after pregnancy. Although disease activity was stable throughout the study period, we found that DAS28 6 weeks postpartum increased significantly compared to the first trimester (2.78 vs 2.51, p = 0.005) and third trimester (2.78 vs 2.56, p = 0.011), respectively. DAS28 decreased significantly between 6 weeks and 12 months postpartum (2.78 vs 2.54, p = 0.014). Self-reported mental health was significantly better 6 weeks postpartum than before pregnancy (Medical Outcomes Study Short Form-36 Mental Health subscale 80.7 vs 76.5, p = 0.039). Self-reported pain was stable. Physical function was significantly worse in the third trimester of pregnancy than postpartum (Modified Health Assessment Questionnaire 0.57 vs 0.39, p < 0.001).

Conclusion In women with JIA, disease activity was highest 6 weeks postpartum, but altogether low and stable in the period from planning pregnancy to 1 year after delivery.