A groundbreaking French multicenter study shed new light on how pregnancy affects disease activity in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA). The GR2 cohort, spanning from 2014 to 2022, provided a real-world perspective on the evolving interplay between inflammatory rheumatic disease and pregnancy.
The analysis included 124 pregnant women, 53 with RA and 71 with SpA, who had at least two prenatal assessments, one of which occurred in the first trimester. TNF inhibitors were used by 35% of RA and 62% of SpA patients during pregnancy. Across trimesters, disease activity scores (DAS28-CRP for RA; ASDAS-CRP and/or BASDAI for SpA) remained generally low and stable at the group level. Despite these reassuring trends, disease relapse occurred in 32% of RA and 39% of SpA patients. Treatment intensification, defined as the initiation or switch of a DMARD, was necessary in 24% of cases. The study’s multivariable analysis uncovered important predictors of relapse risk. For RA patients, nulliparity increased relapse odds by 6.5 times, while experiencing a disease flare in the year before conception raised risk by 8.2 times. SpA patients with prior biological DMARD use faced 5.4 times higher odds of relapse during pregnancy.
Pregnancy is believed to exert immunomodulatory effects that promote maternal tolerance to the semi-allogeneic fetus, potentially contributing to the improvement of RA. However, the precise mechanisms behind this spontaneous disease modulation remain unclear. While the improvement of RA symptoms during pregnancy has been recognized for decades, much of the supporting evidence comes from older, retrospective studies. A reduction in disease activity has also been observed, though less consistently, in psoriatic arthritis. In contrast, findings in axial SpA are more variable, with some studies reporting increased disease activity, particularly during the second trimester. Despite potential improvements, active disease during pregnancy has been documented in 35–52% of RA patients and 60–80% of those with axial SpA.
A systematic review and meta-analysis by Jethwa et al. evaluated RA disease activity during and after pregnancy using objective, clinician-assessed scoring systems. Ten prospective studies involving 237 patients met the inclusion criteria. The analysis showed that 60% of patients experienced an improvement in disease activity during pregnancy, while 47% had a relapse in the postpartum period. Key risk factors for disease flares during pregnancy include active disease at conception and discontinuation of tumor necrosis factor inhibitors (TNFi) early in pregnancy. Postpartum flares are common, typically occurring within the first three months after delivery.
These findings underscore the importance of personalized monitoring strategies tailored to pre-pregnancy disease characteristics. Patients with unstable RA before conception or SpA patients with previous biological therapy require particularly vigilant observation throughout pregnancy to optimize both maternal and fetal outcomes. The research represents a significant advancement in understanding the complex relationship between pregnancy and inflammatory rheumatic diseases, offering rheumatologists valuable guidance for pre-conception counseling and pregnancy management in this vulnerable patient population.
References
- Couderc M, Lambert C, Hamroun S, Gallot D, Costedoat-Chalumeau N, Gossec L, et al; GR2 Study group. Disease activity during pregnancy in patients with rheumatoid arthritis or spondyloarthritis: results from the multicentre prospective GR2 study. BMC Rheumatol. 2025 Mar 11;9(1):30.
- Jethwa H, Lam S, Smith C, Giles I. Does Rheumatoid Arthritis Really Improve During Pregnancy? A Systematic Review and Metaanalysis. J Rheumatol. 2019 Mar;46(3):245-250.