The use of oral corticosteroids was associated with a higher risk for preterm birth in pregnant women with rheumatoid arthritis (RA), according to study results published in Rheumatology.

Researchers retrospectively studied 528 pregnant women with RA who were enrolled in the MotherToBaby Pregnancy Studies from 2003 to 2014. Clinical data was collected via telephone follow-up and review of medical records. The risk for preterm birth was measured using varying corticosteroid cumulative dose levels before and after gestational day 140. In addition, the risks associated with other RA-related drug therapies was evaluated. At the time of enrollment, adjustments were made for RA severity.

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Overall, the researchers found that the risk for preterm birth was 15.5% among study patients. In addition, the risk for preterm birth was greater in patients with high (adjusted relative risk [aRR], 4.77; 95% CI, 2.76-8.26) and medium (aRR, 1.81; 95% CI, 1.10-2.97) corticosteroid dose trajectories up to gestational day 139.

In contrast, the risk observed in the low corticosteroid dose trajectory group was not statistically significant (aRR, 1.38; 95% CI, 0.79-2.38).

One key limitation of the study was its retrospective design.

“Biologic disease-modifying antirheumatic drug (bDMARD) and non-bDMARD use were not associated with preterm birth among women with RA,” the researchers wrote. “In accordance with our hypothesis, high oral corticosteroid doses later in pregnancy were associated with an increase in preterm birth,” they concluded.

Reference

Palmsten K, Bandoli G, Vazquez-Benitez G, Xi M, Johnson DL, Xu R, Chambers CD. Oral corticosteroid use during pregnancy and risk of preterm birth [published online September 30, 2019]. Rheumatology. doi:10.1093/rheumatology/kez405