To determine the effect of rheumatoid arthritis (RA) disease severity on pregnancy outcomes in pregnant women with and without autoimmune diseases.
A prospective cohort study was conducted using the Organization of Teratology Information Specialists Autoimmune Diseases in Pregnancy Project. Pregnant women with RA enrolled between 2005 and 2013 were selected if they (1) delivered a live-born singleton infant; and (2) completed 3 telephone-based measures of RA disease severity prior to 20 weeks' gestation, including the Health Assessment Questionnaire Disability Index (HAQ-DI), pain score, and patient's global scale. Associations between RA disease severity and preterm delivery, small for gestational age (SGA), or cesarean delivery were tested in unadjusted and multivariate analyses using modified Poisson regression models.
The sample consisted of 440 women with RA. Several unadjusted comparisons yielded significant associations. After adjustment for covariates, increasing disease severity was associated with risk for preterm delivery and SGA. For each unit increase in HAQ-DI (0-1), the adjusted relative risk (aRR) for preterm delivery increased by 58% (aRR 1.58, 95% CI 1.17-2.15). Among those with HAQ-DI > 0.5, the aRR for SGA was 1.81 (95% CI 1.01-3.33).
RA disease severity in early pregnancy, as measured in this study, was predictive of preterm delivery and SGA. These findings suggest that the risk of preterm delivery and SGA in women with RA might be lowered if RA is well controlled early in pregnancy.