Idiopathic inflammatory myositis (IIM) commonly affects women in the childbearing age group. Both disease activity and immunosuppressants used may have adverse effects on fertility and outcomes of pregnancy. We explored these outcomes in a cohort of women with IIM.
Women 18 years or older with IIM (Bohan and Peter criteria) were interviewed for demography, menstrual status, history of conception, outcomes, and disease features. Comparisons were drawn between pregnancies occurring before and after onset of disease.
Eighty-one IIM patients with median age of 32 years (interquartile range, 26–50 years) and disease duration of 4 years (interquartile range, 2–9 years) were interviewed. Forty-five patients had dermatomyositis, 20 had polymyositis, and 16 had overlap myositis. Sixty-three patients had conceived before disease onset, resulting in 205 pregnancies and 155 live births over 315.2 patient-years of follow-up.
After disease onset, there were 24 pregnancies (6 live births, 16 spontaneous abortions, and 2 induced abortions) in 7 women over 77.5 patient-years. Of the live births, 1 had cleft palate, 1 had low birth weight, and 1 was preterm. None of the patients who conceived had antiphospholipid antibodies.
Obstetric complications (relative risk [RR] = 7.6; p < 0.0001) and fetal complications (RR = 2.7; p = 0.002) occurred more frequently in pregnancies after the onset of myositis, although there was no difference in maternal complications. Conception after the onset of myositis had higher risk of abortion (RR = 3.6; p < 0.0001).
Women with IIM suffer from poor fetal outcomes as well as high rates of spontaneous abortion rates in the absence of clinical or serologic anti-phospholipid syndrome.