Divergent Blood Pressure Thresholds in Hypertensive Disorders of Pregnancy: A Narrative Review of Global Guideline Discordance and Clinical Implications.

Hypertensive disorders of pregnancy (HDP) remain a leading cause of preventable maternal and perinatal morbidity and mortality. Although blood pressure (BP) thresholds guide diagnosis, treatment, and delivery, international and national guidelines differ, resulting in inconsistent management. This narrative review synthesizes contemporary evidence to map divergences in BP thresholds across global guidelines and evaluate their implications for clinical decision-making and maternal and fetal outcomes, particularly in low- and middle-income countries (LMICs). Comprehensive searches of PubMed, Scopus, Web of Science, and Lens.org were performed. Twenty-five eligible sources, including 12 major international and national guidelines and 13 supporting peer-reviewed sources, were synthesized following SANRA principles. Additional contextual references were cited where necessary but were not counted as included sources in the threshold-synthesis dataset. Diagnostic thresholds, hypertension criteria, treatment initiation thresholds, target BP goals, and magnesium sulfate indications were reviewed. All 12 guidelines uniformly diagnosed hypertension at ≥ 140/90 mmHg. Near-consensus exists for defining severe hypertension at ≥ 160/110 mmHg, though several LMIC guidelines adopt lower thresholds (≥ 150/100-110 mmHg). The most clinically impactful divergence concerns antihypertensive treatment initiation, which varies from ≥ 140/90 mmHg to ≥ 160/110 mmHg, with intermediate thresholds (≥ 150/100 mmHg) used in several LMICs. Additional differences such as the inclusion of fetal growth restriction in some diagnostic frameworks further contribute to misclassification. These inconsistencies create a 20 mmHg "treatment gap," leading to guideline-dependent over- or under-treatment and widening disparities in resource-limited settings. Marked threshold discord across the 12 major HDP guidelines results in systematic misclassification and divergent management pathways. Harmonization initiatives, transparent communication of evidence limitations, and context-specific implementation research, particularly in LMICs, are urgently needed to support equitable, evidence-based maternal care.