(411) Time is money: comparing costs in 12 vs 24 hours of postpartum magnesium

This study evaluates the implementation of a protocol for shortened magnesium sulfate (MAG) duration in postpartum seizure prophylaxis for preeclampsia (preE). We compared MAG administration of 12 vs 24 hours, assessing cost-effectiveness, patient safety, and postpartum length of stay (LOS), utilizing clinical parameters to identify suitable candidates.

Study Design: This interrupted time series and retrospective cohort study evaluated all patients with preE who received MAG and delivered at a tertiary academic center from 04/2022-04/2024. Patients meeting clinical criteria were considered for shortened 12 (G1) vs traditional 24 hour (G2) MAG administration. Primary outcome was difference in mean total hospital cost (MTHC) after delivery pre vs post protocol; secondary outcomes were number of patients with G1 course, rates of postpartum preE readmissions (PPRA), severe maternal morbidity (SMM) and LOS between groups. Wilcoxon rank sum test was applied to compare variables between G1 vs G2, with alpha =0.05 as statistically significant.

Results: A total of 656 patients were evaluated; 53% (n=349) were post protocol, of which 23% (n=80) met criteria for G1. There were no statistically significant differences in gestational age at delivery, delivery for preE, or mode of delivery between pre vs post protocol groups. The MTHC was not significantly different after protocol initiation ($9158 vs $9514, p=0.4) however LOS was shorter post protocol (2.72 vs 3.02 days, p=0.004). Post protocol, G1 had less MTHC ($6840 vs $9850, p = 0.001) and shorter LOS (2.23 vs 2.87 days, p < 0.001). PPRA rates were not significantly different pre protocol (10 vs 6.9%) with RR 0.7 (95% CI 0.4-1.1). Overall SMM was decreased post protocol (7.2% vs 14%, p =0.004) with G1 having lower SMM vs G2 (0% vs 9.3%, p = 0.005).

Conclusion: Shortened MAG course is a cost effective consideration with shortened LOS and decreased PPRA, but likely requires a larger study group to detect overall differences in MTHC. SMM may be decreased with shortened MAG however, direct causation cannot be established.