Optimizing the timing of antenatal corticosteroid administration prior to anticipated preterm birth: A retrospective cohort study.

Objective: To examine suboptimal antenatal corticosteroid (ACS) administration based on indications and maternal-obstetrical factors.

Methods: Women who prematurely delivered (24 + 0 to 36 + 6 gestational weeks) a viable neonate following ACS treatment between 2012 and 2019 were identified by a retrospective database review. The cohort was divided into patients in whom ACS administration was optimally timed (≥24 h to ≤7 days) or suboptimally timed (>7 days). The groups were compared for ACS indications and maternal, obstetrical, and neonatal parameters.

Results: The cohort included 399 women. ACS timing was optimal in 233 patients (58%) and was associated with nulliparity (109 [46.8%] vs. 54 [32.5%], P = 0.004) and preterm premature rupture of membranes (89 [38.2%] vs. 45 [27.1%], P = 0.021). Suboptimal timing was associated with chronic hypertension (22 [9.4%] vs. 36 [21.7%], P < 0.001) and asymptomatic cervical shortening (23 [9.9%] vs. 26 [15.7%], P = 0.020). Optimal ACS timing was associated with higher neonatal intensive care unit admission (135 [58%] vs. 71 [42.8%], P = 0.003). On multivariate analysis, the adjusted odds ratio (aOR) of neonatal intensive care unit admission was 0.69 (95% confidence interval [CI], 0.58-0.83, P < 0.001) and 0.99 (95% CI, 0.99-1, P = 0.003) when adjusted for gestational age and birth weight, respectively. When adjusting for maternal age, the aOR for suboptimal ACS administraion due to chronic hypertension was 2.65 (95% CI, 1.49-4.72; P < 0.001).

Conclusion: Optimal timing of ACS varies based on different maternal characteristics and clinical indications. In the presence of certain parameters physicians tend to administer ACS suboptimally, diminishing its beneficial effect.