(1043) Magnesium sulfate administration in preeclampsia without severe features and perinatal outcomes

Magnesium sulfate (Mg) for seizure prophylaxis is recommended for patients with preeclampsia with severe features. There is no consensus for preeclampsia without severe features (mild preeclampsia), and thus is often left to the discretion of the provider. Our objective was to evaluate neonatal outcomes according to whether Mg was administered for seizure prophylaxis in patients with mild preeclampsia.


Study Design:

Retrospective cohort study of patients with mild preeclampsia who delivered at our institution between November 2021, and May 2022. Patients with fetal anomalies and those delivering at < 32 weeks gestation, given Mg for cerebral palsy prophylaxis, were excluded. The primary outcome was a composite of adverse neonatal outcomes (Figure*). Secondary outcomes included the individual components of the neonatal composite and a maternal bleeding composite (Figure†). Outcomes were compared using chi-squared test and multivariable logistic regression estimated the association between Mg and the outcomes, adjusting for baseline characteristics that were unbalanced between groups.


Results:

Of 583 patients included, 439 (75%) received Mg and 144 (25%) did not. Patients receiving Mg were more likely to have public insurance, comorbidities (cHTN, GDM), aspirin use, earlier GA at delivery, and chorioamnionitis. The composite adverse neonatal outcome was more frequent in patients who received Mg (53% vs. 29%, aOR 1.85, 95% CI 1.13-3.04) than those who did not receive Mg. This was primarily driven by an increase in NICU admission (Figure). While rates of neonates with pH < 7.1 was higher in the no Mg group, there was no difference in other secondary outcomes including maternal bleeding outcomes (Figure).


Conclusion:

We found an increase in adverse neonatal outcomes, primarily NICU admission, in patients receiving Mg for mild preeclampsia. While this data is limited by undetermined indications for NICU admission, further studies are warranted regarding the short and long-term benefits and risks of Mg for mild preeclampsia given the potential for adverse neonatal consequences.