Circulating Biomarkers for Early Preeclampsia Detection

Abstract

Preeclampsia remains a leading contributor to maternal and perinatal morbidity and mortality worldwide, and its early detection is vital to improving clinical outcomes. Circulating biomarkers have emerged as promising tools to identify preeclampsia risk before clinical manifestation. This article reviews the current understanding of circulating biomarkers for early preeclampsia detection, including recent evidence, mechanistic insights, diagnostic approaches, and guideline recommendations, providing clinicians with a comprehensive synthesis for evidence-based practice.

Introduction

Preeclampsia is a hypertensive disorder of pregnancy characterized by new-onset hypertension and proteinuria or end-organ dysfunction after 20 weeks of gestation. Given its often-subclinical early course and rapid potential for progression, early detection and intervention are essential. There is growing interest in the use of circulating biomarkers for preeclampsia risk stratification and prediction, as traditional clinical features frequently lack sensitivity and specificity in early disease stages.

Epidemiology / Disease Burden

Preeclampsia affects approximately 2-8% of pregnancies globally and is a major cause of maternal and fetal morbidity and mortality. Worldwide, it is responsible for nearly 70,000 maternal deaths and 500,000 fetal deaths annually. In low-resource settings, the burden is higher due to delays in diagnosis and limited access to advanced monitoring. Early detection is critical, as timely management can significantly reduce adverse outcomes.

Pathophysiology

Preeclampsia is a complex, multifactorial disorder primarily driven by abnormal placentation. Impaired trophoblast invasion leads to suboptimal spiral artery remodeling, resulting in placental ischemia and the release of antiangiogenic and pro-inflammatory factors into the maternal circulation. This triggers systemic endothelial dysfunction, hypertension, and multi-organ involvement. Key circulating molecules implicated in this process include sFlt-1 (soluble fms-like tyrosine kinase-1), PlGF (placental growth factor), soluble endoglin, and various cytokines, microRNAs, and exosomes.

Risk Factors

Risk factors for preeclampsia encompass both maternal and placental components. High-risk groups include women with a history of preeclampsia, chronic hypertension, diabetes mellitus, renal disease, autoimmune disorders (e.g., lupus, antiphospholipid syndrome), multiple gestations, advanced maternal age, obesity, and nulliparity. Genetic predispositions and preexisting endothelial dysfunction further increase susceptibility. Accurate risk stratification is essential for targeted surveillance and intervention.

Clinical Features

Preeclampsia typically presents after 20 weeks gestation with new-onset hypertension and proteinuria. However, early preeclampsia may be asymptomatic or exhibit subtle manifestations, such as mild elevations in blood pressure, proteinuria, or non-specific symptoms (headache, visual disturbances, epigastric pain). Severe disease can progress rapidly, leading to eclampsia, HELLP syndrome, and end-organ damage. Because clinical features often appear late, biomarker-based detection is a significant advancement.

Diagnosis

Current diagnostic criteria for preeclampsia include blood pressure measurements and laboratory assessment for proteinuria and organ dysfunction. However, these measures are limited in predicting disease onset or severity. Circulating biomarkers, including sFlt-1, PlGF, and the sFlt-1/PlGF ratio, have demonstrated utility in identifying women at increased risk for developing preeclampsia. Studies such as the PROGNOSIS and PARROT trials have validated the predictive power of these markers, particularly when used in combination with clinical algorithms.

Treatment & Management

Management of preeclampsia focuses on maternal stabilization, fetal monitoring, and timely delivery. Antihypertensive therapy, magnesium sulfate for seizure prophylaxis, and corticosteroids for fetal lung maturity are key interventions. Early identification via biomarkers can facilitate closer surveillance, preemptive interventions, and, in select cases, consideration of prophylactic low-dose aspirin. Individualized management plans based on biomarker profiles may optimize outcomes and reduce unnecessary interventions.

Recent Advances / Emerging Therapies

The field of biomarker discovery in preeclampsia has rapidly expanded. Novel candidates, such as angiogenic factors (VEGF, soluble endoglin), microRNAs, extracellular vesicles, and metabolomic signatures, show promise for improving early detection and risk stratification. Integration of multi-marker panels and machine learning algorithms is under investigation to enhance predictive accuracy. Research is also ongoing into targeted therapies aimed at restoring angiogenic balance, though clinical translation remains limited.

Guideline Recommendations

International guidelines, including those from the American College of Obstetricians and Gynecologists (ACOG) and the International Federation of Gynecology and Obstetrics (FIGO), now recognize the value of angiogenic biomarkers particularly the sFlt-1/PlGF ratio in the evaluation of suspected preeclampsia. Their use is recommended as an adjunct to clinical assessment, especially in equivocal cases, to guide further management and timing of delivery. However, they are not yet universally adopted for routine screening due to variability in assay availability and cost considerations.

Conclusion

Circulating biomarkers have transformed the landscape of early preeclampsia detection, offering clinicians objective tools for risk assessment and management. While current evidence supports the integration of angiogenic markers into clinical practice, ongoing research will refine predictive models and identify additional biomarkers. Ultimately, early identification through biomarker-guided strategies has the potential to reduce the burden of preeclampsia and improve maternal-fetal outcomes worldwide.