Pregnancy outcomes in adult patients with dermatomyositis and polymyositis

The idiopathic inflammatory myopathies dermatomyositis (DM) and polymyositis (PM) are autoimmune diseases that can affect females of childbearing potential. We assessed pregnancy outcomes in DM and PM patients compared with the general obstetric population.

The Nationwide Inpatient Sample (NIS) (1993-2007) was used to identify delivery-associated hospitalizations in women with DM or PM (DM/PM, n = 853). Controls were from the general obstetric population delivery-associated hospitalizations matched to each case by year of delivery. Pregnancy outcomes included hospital length of stay (LOS), hypertensive disorders (HTN), premature rupture of membranes (PROM), intrauterine growth restriction (IUGR), and cesarean delivery. Multivariate regression analyses were performed using maternal age, race/ethnicity, and diabetes mellitus as covariates.

On multivariate analysis, patients with DM/PM had longer LOS compared to controls (p < 0.001). DM/PM was associated with an increased risk of hypertensive disorders compared to controls (OR = 2.90, 95% CI: 2.00-4.22). There were no differences in rates of PROM, IUGR, or cesarean section in patients with DM/PM compared with controls. Independent of a DM/PM diagnosis, African-American race, older age, and diagnosis of diabetes increased the hospital LOS (p < 0.001). African-American race and diabetes increased the risk of hypertensive disorders (OR = 1.38, 95% CI: 1.19-1.60; OR = 2.94, 95% CI: 2.04-4.23, respectively) compared to controls.

These data suggest that patients with inflammatory myopathies are at increased risk of hypertensive disorders of pregnancy and longer length of hospitalization. Vigilant monitoring of blood pressure is advisable in pregnant patients with DM or PM.