Background: Women with Systemic Lupus Erythematosus (SLE) have been reported to have higher prevalence of abortion than general population. However, population-based assessment of factors associated with abortion in women with SLE have been scarce.
Objectives: To investigate the factors associated with abortion in women with SLE using a national claims database in Korea.
Methods: This nationwide cohort study used the National Health Insurance Service (NHIS) database in Korea 2002-2018. Study population was women aged 15-49 years with diagnosis of SLE (ICD-10, M32.0 and rare intractable disease registration code, V136). Pregnancy episodes from 2005 to 2017 with at least one SLE-related visits a year before the last menstrual period (LMP) were included. Abortion was defined as a fetal loss of fewer than 20 weeks (ICD-10 codes, O01-O08). To identify the factors associated with abortion, we performed a multivariable logistic regression analysis, including maternal characteristics (age, insurance type, parity, and previous pregnancy loss), comorbidities and SLE-related factors during a year before LMP (antiphospholipid syndrome (APS), renal disease, SLE-related hospitalization), and use of methotrexate (MTX)/mycophenolate mofetil (MMF)/cyclophosphamide (CYC) during 0–3-month preconception period or 1st trimester of pregnancy.
Results: We included 5,044 pregnancy episodes (3,120 women with SLE) with a mean age of 32.4 years (standard deviation 4.3), and abortion occurred in 29.8%. In the multivariable model, age (adjusted odds ratio (AOR) 1.08, 95%CI 1.06-1.10), previous pregnancy loss (AOR 2.06, 95%CI 1.74-2.43), hypertension (AOR 1.57, 95%CI 1.33-1.84), depression (AOR 1.48, 95%CI 1.12-1.96), SLE-related hospitalization (AOR 1.40, 95%CI 1.16-1.60), and use of MMF/MTX/CYC during preconception (AOR 2.3, 95% 1.48-3.51) and 1st trimester (AOR 3.5, 95%CI 2.06-5.78) compared to non-use during the same period were positively associated with abortion. Among women with previous experience of pregnancy loss (n=1,230), the AOR was 1.66 for APS (95%CI 1.06-2.62), 4.77 for MTX/MMF/CYC use during preconception (95%CI 1.52-14.94), and 3.20 for MTX/MMF/CYC use during 1st trimester (95%CI 0.99-16.37).
Conclusions: Along with advanced age, previous pregnancy loss, comorbidities including hypertension and depression, and SLE-related hospitalization, using MMF/MTX/CYC during 0-3-month preconception and 1st trimester, was significantly associated with abortion in pregnant women with SLE. This study reflects the intertwined effects of maternal characteristics, SLE disease activities, and use of teratogenic medications on the abortion of women with SLE.
