Women with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) are associated with an increased risk of PTD (preterm delivery). However, the reason behind this is still unclear.

A prospective cohort study aimed to evaluate the independent impact of factors; medication use, comorbid pregnancy conditions and maternal disease activity attributed to enhance PTD risk among the pregnant women selected before 19 weeks' completed the gestation period. Maternal reports were used to determine data regarding medications, disease activity, pregnancy events, and outcomes which later confirmed using medical outcomes records. The risk ratios (RR), 95% Confidence Intervals (CI) and multivariable adjusted risk ratios (aRR) were assessed using Poisson regression.

The study recruited; 657 women with RA and 170 with JIA and 564 women without the autoimmune disease (comparison group) who gave birth to live-born infants between the years 2004 to 2017. The JIA and RA group showed an enhanced risk of PTD compared to women without any autoimmune disease. The PTD exhibited a significant relationship with active RA at enrollment and anytime during the pregnancy. The Corticosteroid use during each trimester may be linked to enhanced PTD risk up to two- to five-fold.