Oral corticosteroid use during pregnancy and risk of preterm birth

Abstract

Objective: To evaluate the associations between oral corticosteroid (OCS) dose early and late in pregnancy and preterm birth (PTB) among women with RA.

Methods: Pregnant women in the MotherToBaby Pregnancy Studies (2003-2014) with RA (n = 528) were included in the primary analysis. Information was collected by phone interview and from medical records. We estimated risk ratios (RR) for OCS dose trajectories and other disease-related medications before gestational day 140 and hazard ratios (HR) for time-varying exposures after gestational day 139.

Results: PTB risk was 15.5% overall. Compared with no OCS, PTB risk was increased in high (adjusted (a)RR: 4.77 (95% CI: 2.76, 8.26)) and medium (aRR: 1.81 (95% CI: 1.10, 2.97)) cumulative OCS dose trajectories during the first 139 gestational days. The low cumulative trajectory group was associated with an increased risk of PTB that was not statistically significant (aRR: 1.38 (95% CI: 0.79, 2.38)), and DMARDs were not associated with PTB (biologic DMARDs aHR: 1.08 (95% CI: 0.70, 1.66); non-biologic DMARDs aHR: 0.87 (95% CI: 0.55, 1.38)). OCS exposure to ⩾10 mg of prednisone equivalent daily dose after gestational day 139 vs none was associated with increased PTB rate (aHR: 2.45 (95% CI: 1.32, 4.56)), whereas <10 mg was associated with a modestly increased rate of PTB that was not statistically significant (aHR: 1.18 (95% CI: 0.60, 2.30)).

Conclusion: Higher OCS doses vs no OCS use, both earlier and later in pregnancy, were associated with an increase in PTB among women with RA.

Keywords: antirheumatic agents; autoimmune diseases; oral corticosteroids; pregnancy; preterm birth; rheumatoid arthritis.

Fig. 1

Study cohort diagram Fifteen women were in both the rheumatoid arthritis and IBD subcohorts, 11 women were in both the RA and asthma subcohorts, seven women were in both the IBD and asthma subcohorts, and one woman was in all three subcohorts. LMP: last menstrual period; OCS: oral corticosteroid; ICS: inhaled corticosteroid; LABA: long-acting beta-agonist; LTRA: leukotriene receptor agonist; SABA: short-acting beta-agonist. ^an = 524 women with oral corticosteroid dose information available before gestational day 140, n = 525 women with oral corticosteroid dose information available after gestational day 109. ^bn = 216 women with oral corticosteroid dose information available before gestational day 140.

Fig. 2

Oral corticosteroid cumulative dose trajectories between the last menstrual period and gestational day 139 (n = 254) The thick lines represent the mean cumulative dose on each gestational day for each group and the thin lines represent each woman’s observed trajectory; blue = high, green = medium and red = low dose trajectories.