Psoriatic Arthritis Disease Activity During and After Pregnancy: A Prospective Multicenter Study.

Objective: To study disease activity in women with peripheral psoriatic arthritis (PsA) during and after pregnancy. Previous knowledge on this topic is sparse.

Methods: The study included 108 pregnancies in 103 women with PsA from a Norwegian nationwide register. Disease activity was assessed prospectively at 7 time points before, throughout, and after pregnancy with the 3-variable Disease Activity Score in 28 joints (DAS28) using C-reactive protein levels and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Scores assessed at each time point were analyzed in a linear mixed model. We did additional analyses with "tumor necrosis factor inhibitor (TNFi) in pregnancy" as a covariate. The same statistical method was used to study self-reported physical function, pain, and mental health.

Results: Approximately 75% of the women were in remission or had low disease activity during and after pregnancy according to the DAS28-CRP score. Although disease activity was altogether stable, we found that it decreased in pregnancy and increased within 6 months postpartum. Disease activity at 6 months postpartum was significantly higher than at 6 weeks postpartum (mean DAS28-CRP score 2.71 versus 2.45; P = 0.016). Women using TNFi in pregnancy had significantly lower disease activity than women not using TNFi (mean DAS28-CRP score at 6 months postpartum 2.22 versus 2.72; P = 0.043). BASDAI scores were also low and stable during pregnancy but significantly higher at 6 months postpartum than at 6 weeks postpartum (mean BASDAI score 3.69 versus 2.95; P = 0.013).

Conclusion: Studying women with PsA, we found that disease activity was highest at 6 months postpartum but altogether low and stable in the period from planning pregnancy to 1 year after delivery. Women using TNFi in pregnancy had significantly lower disease activity.