Prevalence and significance of previously undiagnosed rheumatic diseases in pregnancy

Objectives: The objective of this study was to evaluate the rates of previously undiagnosed rheumatic diseases during the first trimester of pregnancy and their impact on the pregnancy outcome. Methods: Pregnant women in their first trimester were screened using a two-step approach using a self-administered 10-item questionnaire and subsequent testing for rheumatic autoantibodies (antinuclear antibody, anti-double-stranded DNA, anti-extractable nuclear antigen, anticardiolipin antibodies, anti-β2-glycoprotein I antibodies and lupus anticoagulant) and evaluation by a rheumatologist. Overall, the complications of pregnancy evaluated included fetal loss, pre-eclampsia, gestational diabetes, fetal growth restriction, delivery at less than 34 weeks, neonatal resuscitation and admission to the neonatal intensive care unit. Results: Out of the 2458 women screened, the authors identified 62 (2.5%) women with previously undiagnosed undifferentiated connective tissue disease (UCTD) and 24 (0.98%) women with previously undiagnosed definite systemic rheumatic disease. The prevalences were seven (0.28%) for systemic lupus erythematosus and Sjogren's syndrome, six (0.24%) for rheumatoid arthritis, three (0.12%) for antiphospholipid syndrome and one (0.04%) for systemic sclerosis. In multiple exact logistic regression, after adjustment for potential confounders, the OR of overall complications of pregnancy were 2.81 (95% CI 1.29 to 6.18) in women with UCTD and 4.57 (95% CI 1.57 to 13.57) in those with definite diseases, respectively, compared with asymptomatic controls. Conclusions: In our population approximately 2.5% and 1% of first trimester pregnant women had a previously undiagnosed UCTD and definite systemic rheumatic disease, respectively. These conditions were associated with significant negative effects on the outcome of pregnancy.