Objective: While antenatal corticosteroids (ACS) administered in the late preterm period have been shown to reduce respiratory morbidity, this finding was demonstrated in a well-designed randomized controlled trial (the Antenatal Betamethasone for Women at Risk for Late Preterm Delivery [ALPS]) with strict inclusion/exclusion criteria that may differ from clinical practice. The aim of this study was to investigate whether there has been indication creep since use of late preterm ACS became standard of care.
Study design: Retrospective cohort study of pregnant women who received late preterm ACS between 2016 and 2019 were identified and separated into epochs of 2016 to 2017 and 2018 to 2019 based on year of exposure. The primary outcome was rate of inappropriate ACS exposure, defined as nonadherence to the inclusion/exclusion criteria of the ALPS trial. Secondary outcomes were rates of nonoptimal ACS exposure (delivery >7 days from ACS or term delivery). Logistic regression was used to generate adjusted odds ratios (aORs) between epochs for the primary outcome adjusting for confounders.
Results: There were 660 women who received late preterm ACS during the study period with 229 (34.6 %) deemed inappropriate exposures. The most common reason for inappropriate treatment was preterm premature rupture of membrane (PPROM; 29.0%) with exclusionary cervical examination or contraction frequency. No difference was observed in inappropriate ACS exposure between epochs (aOR = 0.83, 95% confidence interval [CI]: 0.59-1.2). However, there was a reduction in nonoptimal exposure over time (aOR = 0.67, 95% CI: 0.47-0.97) . Women receiving inappropriate ACS were more likely to deliver at term if indicated for maternal/fetal status (50.0 vs. 19.5%, p < 0.001) and preterm labor (66.0 vs. 41.9%; p = 0.015). Further, inappropriate exposure in preterm labor had higher rates of exposure latency >7 days (62.3 vs. 39.1%, p = 0.006) with a longer latency to delivery (3 vs. 16 days; p < 0.001).
Conclusion: Over one-third of women received late preterm ACS for an indication that could be classified as indication creep. Depending on indication, inappropriate administration is associated with higher rates of nonoptimal exposure.
Key points: · There is potential for indication creep of ACS administration.. · One third of late preterm ACS exposures in our study were inappropriate.. · Utilizing clinical criteria can aid in identifying patients who best benefit from late preterm ACS..
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