To assess the influence of maternal cytokine levels, disease activity and severity on preterm delivery, small for gestational age (SGA) and cesarean delivery in pregnant women with rheumatoid arthritis (RA).
A prospective study in 47 pregnant women with RA and 22 healthy pregnant controls. The main outcome measures were birth weight in relation to maternal serum levels of interleukin-6 (IL-6), interleukin-10 (IL-10), and RA activity and severity at three different time points: preconception and during the first and third trimesters.
During the third trimester, IL-10 was detectable in 23.4% of patients with RA, IL-6 in 76.6%. Mean birth weight born to mothers with RA was higher when IL-10 level was high compared with low (p = 0.001), and lower when IL-6 was high compared with low (p = 0.035). Also increase in disease activity score-28 (in 60.1%, p = 0.001), Health Assessment Questionnaire-Disability Index (in 87.5%, p = 0.013), and pain score (56.9 ± 11.4, p = 0.003) associated with increased risk of SGA. High patient's global scale was associated with unfavorable pregnancy outcome (preterm, SGA, and cesarean).
High maternal IL-10 levels are associated with higher birth weight and high IL-6 levels are associated with lower birth weight (SGA). Among women with RA, disease activity and severity are predictive of unfavorable pregnancy outcomes suggesting that better disease management early in the pregnancy could improve pregnancy outcomes.