The Effect of Magnesium Sulfate in the Treatment of Maternal Postpartum Hypertension on Breastfeeding: An Integrative Review.

BACKGROUND

Magnesium sulfate is widely prescribed postpartum for seizure prophylaxis in women with preeclampsia and other hypertensive disorders of pregnancy, yet its potential effects on lactation outcomes remain underexplored.

OBJECTIVES

To evaluate and synthesize the current evidence on how postpartum magnesium sulfate therapy affects lactation outcomes, including breastfeeding initiation, exclusivity, duration, pumping habits, and secretory activation (SA).

METHODS

This integrative review followed PRISMA guidelines and Whittemore and Knafl's framework. Literature was obtained from five databases without date restrictions. A total of 11 studies met the inclusion criteria. Methodological quality was evaluated using the Joanna Briggs Institute tools and Melnyk and Fineout-Overholt's hierarchy of evidence.

RESULTS

Data were synthesized from 11 studies published between 1993 and 2023, encompassing 2,842 participants across diverse hospital settings. Findings indicate that extended postpartum magnesium sulfate administration is associated with delayed breastfeeding initiation, delayed maternal perception of SA, and greater reliance on milk expression. Most researchers did not report maternal side effects or quantitatively measure the frequency of breastfeeding or pumping. Studies reported hospital policies that restricted rooming-in and breastfeeding during magnesium infusion.

CONCLUSIONS

Postpartum magnesium sulfate administration is associated with delays in lactation initiation, missing the evidence-based critical window for frequent early milk removal. However, studies in this review rarely examine maternal side effects or feeding frequency in detail. Future research should use standardized definitions, document both frequency and mode of milk removal, evaluate objective measures of SA, evaluate maternal experience, and hospital policies.