title: Pregnancy in polymyositis or dermatomyositis: retrospective results from a tertiary centre in China.
abstract: To examine if patients with PM/DM are at higher risk of complicated pregnancies.
  
  
  
  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.
  
  
  
  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.
  
  
  
  PM/DM, especially those less well controlled, might contribute to an increased risk of complicated pregnancy.
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: Department of Rheumatology, Zhangzhou Municipal Hospital, Fujian Province.
authors.forename: Fuan
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Emergency, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing.
authors.forename: Fengchun
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing.
authors.forename: Xin
authors.initials: X
authors.lastname: You
mesh_terms: D000022:Abortion, Spontaneous / Q000209:etiology; D000328:Adult; D002681:China; D003882:Dermatomyositis / Q000150:complications*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D016017:Odds Ratio; D017285:Polymyositis / Q000150:complications*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology*; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors
keywords: generalized linear mixed effect models; outcome; polymyositis/dermatomyositis; pregnancy