For clinicians

Dermatomyositis and inflammatory myopathies

dermatomyositis, polymyositis, idiopathic inflammatory myopathy, IIM, myositis

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Bottom lineBottom line: outcomes are strongly tied to disease activity, with best results when conception follows sustained remission (commonly cited as >=6 months) on compatible therapy. Active disease is associated with pregnancy loss, prematurity, and growth restriction. Continue hydroxychloroquine (skin) and azathioprine; use glucocorticoids or IVIG for activity; avoid methotrexate, mycophenolate, and cyclophosphamide. Screen for anti-Ro co-positivity.

By domain

Plan around remission ●●●○moderate evidencestrong

Conception during sustained remission on compatible therapy is the key modifiable predictor; active disease at conception predicts worse outcomes.[1, 3]

Will myositis affect the pregnancy? ●●○○low evidenceconditional

Active myositis is associated with higher pregnancy loss, preterm birth, and growth restriction; across retrospective cohorts fetal loss was more frequent with active than inactive disease (roughly 42-57% vs 14-29%). Quiescent disease has substantially better outcomes. The evidence is limited to case reports and small retrospective cohorts, so the numbers carry wide uncertainty and reporting bias toward severe cases.[3]

Will pregnancy affect my myositis? ●●○○low evidenceconditional

Disease can be active, or first present, during pregnancy or postpartum; in the reviewed cases new onset clustered in the first trimester. Monitor muscle enzymes, strength, skin, and for dysphagia or respiratory muscle weakness (severe respiratory failure needing ventilation occurred in about 13% of the published during-pregnancy cases).[3]

Delivery planning ●●○○low evidenceconditional

Where muscle strength is affected, plan delivery mode in advance: planned caesarean has been suggested to avoid rhabdomyolysis and the risk of an emergent caesarean from muscle fatigue in vaginal delivery. Caesarean was used in about 60% of the published during-pregnancy cases, though this reflects selected case reports rather than a delivery recommendation.[3]

Medicines ●●●○moderate evidenceconditional

Continue hydroxychloroquine and azathioprine; glucocorticoids and IVIG for active disease; avoid methotrexate, mycophenolate, cyclophosphamide. Individualise other agents.[1, 2]

Antibody testing ●●○○low evidenceconditional

Screen for anti-Ro/SSA co-positivity, which triggers the neonatal-lupus and congenital heart block pathway.[1]

Key points

PointEvidence
Sustained pre-conception remission on compatible therapy is the central planning goal.[1]●●●○moderate evidencestrong

References

  1. Sammaritano LR, et al. 2020 ACR Guideline for the Management of Reproductive Health in RMD. Arthritis Rheumatol. 2020;72(3):529-556. https://acrjournals.onlinelibrary.wiley.com/doi/10.1002/art.41191
  2. Ruegg L, et al. EULAR recommendations for antirheumatic drugs in reproduction, pregnancy, and lactation: 2024 update. Ann Rheum Dis. 2025;84(6):910-926. https://ard.eular.org/article/S0003-4967(25)00818-0/fulltext
  3. Ito Y, Yamamoto Y, Suzuki Y, Noda K, Nakajima A. Clinical and Serological Features and Pregnancy Outcomes in Women with Polymyositis/Dermatomyositis: A Case-based Review. Intern Med. 2022;61(2):143-149. https://doi.org/10.2169/internalmedicine.7924-21