Adverse Pregnancy Outcomes in Adult Patients With Idiopathic Inflammatory Myopathy: A Systematic Review and Meta-Analysis.

Abstract

Objective: Studies of the impact of idiopathic inflammatory myopathy (IIM) and its pregnancy complications have yielded controversial results. The purpose of this study was to perform a systematic literature review and meta-analysis to evaluate the association between IIM and adverse pregnancy outcomes.

Methods: PubMed, Embase, and Web of Science databases were searched to identify reports of interest. The databases were searched from establishment to May 15, 2025. Two investigators independently screened literature and extracted data according to inclusion and exclusion criteria. The Newcastle-Ottawa Scale was used for quality assessment. A random-effects model with inverse-variance weighting was selected to estimate the pooled odds ratio (OR) and 95% confidence interval (CI). Data analysis was performed using Review Manager 5.3.

Results: This analysis included five population-based retrospective cohorts, predominantly comprising patients with dermatomyositis or polymyositis; thus, the pooled estimates primarily reflect these subtypes. Compared to pregnant patients without IIM, patients with IIM had significantly higher risks of hypertensive disorders of pregnancy (OR 2.73 [95% CI 1.76-4.23]; I² = 70%, Cochran's Q P = 0.01, overall effect P < 0.00001) and cesarean section (OR 2.03 [95% CI 1.37-3.00]; I² = 79%, Cochran's Q P = 0.002, overall effect P = 0.004). Infants born to birthing parents with IIM also had notably higher rates of being born preterm (OR 3.71 [95% CI 2.35-5.85]; I² = 60%, Cochran's Q P = 0.06, overall effect P < 0.00001) and being small for gestational age or having intrauterine growth restriction (OR 1.90 [95% CI 1.03-3.51]; I² = 43%, Cochran's Q P = 0.15, overall effect P = 0.04).

Conclusion: Our meta-analysis showed IIM to be associated with increased risk of hypertensive disorders of pregnancy, cesarean section, preterm birth, and infants who are small for gestational age or had intrauterine growth restriction, although residual confounding by disease activity and treatment may contribute.