Pregnancy in polymyositis or dermatomyositis: Retrospective results from a tertiary centre in China

Abstract

Objective. To examine if patients with PM/DM are at higher risk of complicated pregnancies. Methods. In a retrospective cohort in a large tertiary centre in North China, the outcomes of 144 pregnancies were evaluated in 62 women with PM/DM. Generalized linear mixed effect models were fitted to assess the effect of pregnancy occurring after disease on pregnancy outcomes including preterm birth (PTB), abortion (spontaneous or induced) and normal delivery. Adjustment for confounding factors including parity, maternal age and pregnancy-disease interval were achieved with a multivariable model. Results. For women who became pregnant after disease onset, there was significantly higher risk of either PTB or spontaneous abortion (adjusted odds ratio, OR = 9.36, 95% CI: 1.10, 79.88; P = 0.041). The odds increase was more prominent if PM/DM was also active during pregnancy (adjusted OR = 435.35, 95% CI: 5.32, 35628.18; P = 0.007). Disease flare upon conception was observed in 4 of 22 post-PM/DM pregnancies (P = 0.125), and responded well to steroids and IVIG but resulted in PTB or spontaneous abortion. Conclusion. PM/DM, especially those less well controlled, might contribute to an increased risk of complicated pregnancy.