Factors Associated With Time to Pregnancy in Women With Axial Spondyloarthritis: A Registry-Based Multicenter Study

Abstract

Objective: The present study was undertaken to study time to pregnancy (TTP) and factors associated with TTP in women with axial spondyloarthritis (SpA) compared to women with rheumatoid arthritis (RA). Methods: We included 274 women with axial SpA and 317 women with RA from the Norwegian nationwide registry RevNatus. For all the women, we had retrospectively collected data on TTP, and a subgroup also had prospectively collected data. We compared TTP in women with axial SpA to women with RA using Kaplan-Meier plots and a log rank test. To identify factors associated with TTP, we used Cox proportional hazards regression. Results: TTP exceeded 12 months in 21% of women with axial SpA. In the subgroup followed prospectively, 32% had TTP that exceeded 12 months. Longer TTP was associated with older age, nulliparity, and longer disease duration, with hazard ratios of 0.97 (95% confidence interval [95% CI] 0.94–1.00), 0.66 (95% CI 0.50–0.88), and 0.94 (95% CI 0.91–0.98), respectively. Disease activity, medication, and self-reported health-related quality of life were not associated with TTP. We found no statistically significant differences between axial SpA and RA in regard to TTP. Conclusion: In women with axial SpA, longer TTP was associated with older age, nulliparity, and longer disease duration.