# Beyond magnesium sulphate – Rethinking magnesium’s impact on maternal and foetal health in low to middle-income countries: A scoping review

## TL;DR

This review explores how magnesium levels may affect pregnancy complications in low- and middle-income countries, highlighting gaps in understanding and suggesting areas for future research.

## Contribution

The study maps current evidence on magnesium's role in pregnancy-related hypertension and identifies research gaps specific to low-resource settings.

## Key findings

- Lower magnesium levels are observed in women with hypertensive disorders of pregnancy compared to controls.
- Magnesium appears to influence endothelial function and oxidative stress, potentially linking low levels to adverse outcomes.
- Supplementation trials show inconsistent results due to differences in study design and population factors.

## Abstract

Hypertensive disorders of pregnancy (HDP), contribute greatly to maternal and perinatal morbidity and mortality, particularly in low-and middle-income countries (LMICs), undermining progress towards reducing maternal mortality. While magnesium sulphate is established for seizure prophylaxis, magnesium’s physiological and epidemiological significance in HDPs is underexplored. This scoping review mapped current evidence on maternal magnesium homeostasis and HDP association.

Electronic databases were searched for studies reporting maternal magnesium levels, magnesium physiology in pregnancy or, magnesium supplementation in HDP. Eleven studies met the eligibility inclusion criteria. Data was charted for study design, magnesium biomarkers, outcomes and contextual factors.

Observational evidence demonstrated lower magnesium levels among women with HDP against normotensive controls and linked low magnesium with adverse foetal outcomes. Mechanistic studies supported this, highlighting magnesium’s role in endothelial function, vascular tone regulation and oxidative stress. Randomised trials evaluating magnesium supplementation showed inconsistent findings and were influenced by variations in formulation, dosage, timing and, underlying nutritional status. Contextual factors, such as HIV, obesity, renal function, and socioeconomic disadvantage, impacted magnesium homeostasis and HDP risk, particularly in LMICs.

Magnesium insufficiency may contribute to HDP and adverse perinatal outcomes in LMICs, though causal pathways remain unconfirmed. Improved biomarker standardisation, mechanistic studies, and targeted supplementation trials in high-risk or deficient populations are needed.

This review highlights key inconsistencies in magnesium measurement, identifies contextual modifiers relevant to LMICs, and outlines priority areas for future research.