Preeclampsia with lower serum sodium levels: implications for maternal antihypertensive medication use

OBJECTIVE: To determine whether patients with preeclampsia and lower serum sodium levels require emergency or long-acting antihypertensives more frequently than those with higher sodium levels. STUDY DESIGN: This retrospective cohort study included preeclampsia (PE) patients admitted to Mount Sinai Health System between January 1, 2013, and December 31, 2021, with at least one documented serum sodium value during their delivery or postpartum admission. Patients were categorized by nadir sodium into three groups: preeclampsia with hyponatremia (PET-HNa; sodium < 130 mmol/L), preeclampsia with lower serum sodium (PALS; sodium 130-134 mmol/L), and preeclampsia with higher serum sodium (PAHS; sodium ≥ 135 mmol/L).. MAIN OUTCOME MEASURES: Primary outcomes were need for emergency antihypertensives during admission and long-acting antihypertensives at discharge. Secondary outcomes were maternal length of stay (LOS), need for intensive care unit (ICU) admission or readmission for PE. RESULTS: 662 PE patients were included. Compared to PAHS patients, PALS patients were more likely to be older, nulliparous, diagnosed with PE with severe features, and require longer LOS. In unadjusted analyses, PALS patients were more likely to require long-acting antihypertensives; this association did not reach statistically significance after adjustment for confounders. PET-HNa patients had higher rates of ICU admission and longer LOS versus PAHS patients. No differences were observed in emergency antihypertensive use or PE-related readmission across groups. CONCLUSIONS: Lower serum sodium levels in PE are associated with markers of disease severity and prolonged LOS. PET-HNa identifies a high-risk subgroup with increased ICU utilization, warranting closer attention to sodium levels in PE management.