Maternal Endothelial Activation Biomarkers in Pregnancy Adaptation

Abstract

Endothelial activation is a crucial physiological and pathological process during pregnancy, underpinning maternal adaptation to gestational demands. The assessment of maternal endothelial activation biomarkers provides new insights into normal pregnancy adaptation as well as obstetric complications. This review synthesizes current evidence on the pathophysiological role, clinical relevance, and diagnostic utility of endothelial activation biomarkers, highlighting their significance for clinicians and researchers in maternal-fetal medicine.

Introduction

Pregnancy induces profound systemic and vascular adaptations to support fetal growth and maternal health. The endothelium plays a pivotal role in these changes, with controlled activation facilitating vascular remodeling, immune regulation, and hemostatic balance. However, excessive or dysregulated endothelial activation can precipitate pathological states such as preeclampsia, fetal growth restriction, and other adverse outcomes. Biomarkers of endothelial activation, including soluble adhesion molecules, selectins, and angiogenic factors, have emerged as valuable tools for understanding and monitoring these processes. Their measurement enables risk stratification, early diagnosis, and potential therapeutic intervention in pregnancy-related disorders.

Epidemiology / Disease Burden

Globally, hypertensive disorders in pregnancy—most notably preeclampsia—affect 5–8% of pregnancies and are leading causes of maternal and perinatal morbidity and mortality. Endothelial dysfunction is a central feature in these conditions, contributing to their high disease burden. Subclinical endothelial activation is also observed in pregnancies complicated by gestational diabetes and intrauterine growth restriction. Early identification of at-risk pregnancies using sensitive biomarkers could help reduce adverse outcomes and healthcare burden, particularly in low-resource settings where maternal complications remain prevalent.

Pathophysiology

Endothelial activation refers to a shift in endothelial cell phenotype, characterized by increased expression of cell adhesion molecules, cytokine production, heightened permeability, and procoagulant activity. In normal pregnancy, mild endothelial activation supports placental vascular development and maternal adaptation. However, excessive activation, often triggered by abnormal placentation, oxidative stress, or systemic inflammation, underpins pathologies such as preeclampsia. Key biomarkers include soluble vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1), E-selectin, and angiogenic regulators such as soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF). Dysregulated angiogenic balance and heightened endothelial activation disrupt vascular homeostasis, contributing to hypertension, proteinuria, and end-organ damage.

Risk Factors

Several maternal, fetal, and environmental factors predispose to aberrant endothelial activation during pregnancy. These include chronic hypertension, preexisting diabetes mellitus, obesity, advanced maternal age, autoimmune diseases, multiple gestation, and a history of preeclampsia. Genetic predispositions, oxidative stress, and inflammatory states further compound risk. Environmental exposures, such as tobacco use and air pollution, may also modulate endothelial activation and biomarker profiles. Recognizing risk factors aids in the targeted application of biomarker screening and preventive strategies.

Clinical Features

Clinically, endothelial activation may manifest as systemic hypertension, proteinuria, and edema—hallmarks of preeclampsia. Subtle features include altered vascular reactivity, increased arterial stiffness, and microvascular dysfunction, which may precede overt symptoms. Intrauterine growth restriction and placental abruption are also linked to maternal endothelial dysfunction. Biomarkers measured in maternal blood can signal subclinical activation, allowing for preemptive monitoring and intervention before clinical decompensation occurs.

Diagnosis

Current diagnostic strategies for pregnancy-related endothelial dysfunction rely on clinical and laboratory parameters. However, the incorporation of biomarkers such as sFlt-1, PlGF, sVCAM-1, and sICAM-1 has enhanced diagnostic precision. The sFlt-1/PlGF ratio, in particular, is increasingly utilized to differentiate preeclampsia from other hypertensive disorders and to predict disease onset and severity. High-throughput immunoassays and point-of-care testing are being developed for rapid biomarker quantification, offering promise for early detection and risk stratification in clinical practice.

Treatment & Management

Management of endothelial activation in pregnancy primarily focuses on mitigating underlying causes and preventing progression to severe disease. Antihypertensive therapy, close fetal surveillance, and timely delivery remain standard interventions. Recent evidence supports the use of low-dose aspirin for preeclampsia prevention in high-risk women, possibly via its anti-inflammatory and anti-platelet effects on the endothelium. There is growing interest in therapies targeting angiogenic imbalance, such as recombinant PlGF or agents neutralizing sFlt-1, though these remain investigational. Lifestyle modification and optimized management of comorbidities are also essential components of care.

Recent Advances / Emerging Therapies

Recent advances include the development of multiplex biomarker panels and personalized risk prediction algorithms integrating clinical and molecular data. Novel agents targeting the angiogenic pathway, including sFlt-1 inhibitors and PlGF analogs, are under early-phase investigation, with the aim of restoring endothelial balance in preeclampsia. Extracorporeal removal of sFlt-1 has been explored as a rescue therapy in severe cases. Omics technologies and machine learning are being harnessed to identify new biomarkers and therapeutic targets, potentially revolutionizing the management of pregnancy complications related to endothelial activation.

Guideline Recommendations

International guidelines, including those by the American College of Obstetricians and Gynecologists (ACOG) and the International Society for the Study of Hypertension in Pregnancy (ISSHP), recognize the significance of endothelial activation in pregnancy disorders. They recommend the use of angiogenic biomarkers, particularly the sFlt-1/PlGF ratio, for the evaluation of suspected preeclampsia and risk stratification. Aspirin prophylaxis is advised for women at high risk of preeclampsia. Ongoing research may soon expand guideline recommendations to incorporate novel biomarkers and targeted therapies as evidence matures.

Conclusion

Maternal endothelial activation biomarkers represent a vital link between placental biology, maternal adaptation, and pregnancy outcomes. Their clinical utility extends from early risk assessment to diagnosis and targeted management of pregnancy complications. Ongoing research is poised to refine their role, heralding an era of precision medicine in maternal-fetal care. Clinicians should remain abreast of emerging evidence and integrate validated biomarkers into holistic, guideline-based patient management to improve maternal and neonatal health.