Prevalence of undiagnosed autoimmune rheumatic diseases in the first trimester of pregnancy. Results of a two-steps strategy using a self-administered questionnaire and autoantibody testing

Objective: To evaluate the prevalence of undiagnosed rheumatic diseases in the first trimester of pregnancy. Design: We screened for rheumatic diseases in 1210 consecutive pregnant women during the first trimester of pregnancy using a 10-item questionnaire. Setting: A university hospital in northern Italy. Population: One hundred and thirty-seven (11.3%) women who answered positively to at least one question constituted the cases and were compared with 107 negative controls. Methods: Cases and controls were tested for rheumatic autoantibodies (antinuclear antibody, anti-double-stranded DNA, anti-extractable nuclear antigen, anticardiolipin antibody, anti-β2-glycoprotein I antibodies and lupus anticoagulant) and were evaluated by a rheumatologist for a definite diagnosis of rheumatic disease. Main outcome measures: Prevalence of undiagnosed rheumatic disease in the first trimester of pregnancy. Results: The overall rate of positivity to the antibodies tested was 43.1% (59/137) among cases and 9.3% (10/107) in the controls (P <0.001). A definitive diagnosis of rheumatic disease was made in 35 cases (25.5%) and in none of the controls (P