Impact of pregnancy on progression of preclinical autoimmune disorders: a prospective cohort study

Objectives The objective of this study was to evaluate the role of pregnancies in the progression from the preclinical phase of autoimmune disorder to a definite rheumatic disease. Methods A cohort study of women with symptoms and laboratory findings suggestive for autoimmune disorder were enrolled during the first trimester of pregnancy and followed-up for 5 years with clinical and laboratory assessment. Multinomial logistic regression was used to compute the risk of progression to definite autoimmune disease correcting for confounders. Results At the end of follow-up, out of 208 subjects, 81 (38.9%) were considered negative, 53 (25.5%) had symptoms and abnormalities of autoantibody profile compatible with a non-criteria rheumatic status and 74 (35.6%) had a definite rheumatic disease (43 undifferentiated connective tissue disease, 5 systemic lupus erythematosus, 3 SS, 10 antiphospholipid syndrome, and 12 miscellaneous autoimmune disorders). The median time from enrolment to definite diagnosis was 28 months (interquartile range = 18–42). The rate of progression towards a definite autoimmune disease was 47.1% (48/102) among subjects with one or more subsequent viable pregnancies compared with 24.5% (26/106) of those with no subsequent pregnancies (adjusted odds ratio = 4.9, 95% CI: 2.4, 10). The occurrence of preeclampsia during the index pregnancy or subsequent pregnancy was an additional and independent risk factor for progression to a definite autoimmune disease (adjusted odds ratio = 4.3, 95% CI: 1.2, 14.8). Conclusions Among women with suspected autoimmune disease during pregnancy, additional viable pregnancies and diagnosis of preeclampsia were independently associated with an increased rate of progression to definite rheumatic disorder. Hormonal modifications associated with pregnancy could worsen preclinical rheumatic disorders favouring their progression to a defined autoimmune disease.