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).
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.
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.
In women with axial SpA, longer TTP was associated with older age, nulliparity, and longer disease duration.