Pregnant women with inflammatory arthritis may be at increased risk for preterm delivery (PTD), yet it is unclear what drives this risk. This aim of this prospective cohort study of pregnant women with rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), or healthier comparison women was to analyze the independent effects of maternal disease activity, medication use, and comorbid pregnancy conditions on PTD risk.
Women were enrolled before 19 weeks completed gestation as part of the Organization of Teratology Information Specialists (OTIS) Autoimmune Disease in Pregnancy Project. Data on pregnancy events, medications, disease activity, and outcomes were obtained by maternal report and validated by medical records. Poisson regression with robust standard errors estimated risk ratios (RR), multivariable adjusted risk ratios (ARRs), and 95% confidence intervals (95% CIs).
A total of 657 women with RA, 170 with JIA, and 564 comparison women without autoimmune disease who delivered live born infants, from 2004 to 2017 were included for analysis. Both the RA and JIA groups had an increased risk of PTD versus the comparison group (RR 2.09 [95% CI 1.50-2.91] and RR 1.81 [95% CI 1.14-2.89], respectively). Active RA at enrollment (ARR 1.58 [95% CI 1.10-2.27]) and any time during pregnancy (ARR 1.52 [95% CI 1.06-2.18]) was associated with PTD. Corticosteroid use in every trimester was associated with an approximate 2- to 5-fold increased risk for PTD for both arthritis groups, independent of disease activity.
Women with RA and women with JIA are at increased risk for PTD. Maternal disease activity and corticosteroid use may contribute to some of this excess risk.