This cohort study describes that women with rheumatoid arthritis, and juvenile idiopathic arthritis are at increased risk of PTD. It was also noted some of this risk might be due to maternal disease activity and corticosteroid.

Very few studies have been conducted in pregnant women with inflammatory arthritis who are at high risk for preterm delivery (PTD). The pregnant women with RA, JIA, or healthier comparison women investigated the individualistic effects of maternal disease activity, medication use, and comorbid pregnancy conditions on the risk of PTD in this prospective cohort study.

As a part of the Organization of Teratology Information Specialists (OTIS) Autoimmune Disease in Pregnancy Project, the women were enrolled before 19 weeks’. Data on pregnancy events, disease activity, medications, and outcomes were gathered by maternal report and confirmed by medical records. The Poisson regression with robust standard errors revealed risk ratios (RR), multivariable adjusted risk ratios (aRR) and 95% Confidence Intervals (CI).

For the analysis, a total of 657 women with RA: 170 with JIA, and 564 comparison women without the autoimmune disease who delivered live‐born infants from 2004 to2017 were included. Both the RA and JIA groups had an increased risk of PTD than the healthy comparison group. Active RA at the time of enrollment (aRR 1.58, 95% CI 1.10‐2.27) and anytime during the pregnancy (aRR 1.52, 95% CI 1.06‐2.18) was concerned with PTD. The corticosteroid use in every trimester was concerned with an approximate 2 to 5‐fold augmented risk for PTD for both arthritis groups, independent of disease activity.

The women suffering from RA and JIA are at increased risk for PTD. Maternal disease activity and corticosteroid use may contribute to some of this excess risk.