Biomarker blood test revolutionizes preeclampsia care

The U.S. maternal mortality rate has been rising over recent decades and is one of the highest among developed nations, with preeclampsia and hypertensive pregnancy disorders being major contributing factors.¹ However, with recent developments, the country is on the brink of experiencing the transformative impact of biomarker-based care in reducing the widespread risks associated with preeclampsia.

In fact, in 2023, the U.S. Food and Drug Administration (FDA) cleared a novel blood test² to aid in the risk assessment of preeclampsia with severe features (sPE) in hospitalized pregnant women. Though still in its early stages, the test, which consists of two placental biomarker measurements — soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) — is already paving the way for significant advances in predicting and managing this life-threatening pregnancy complication.

Understanding preeclampsia and the need for early detection

Preeclampsia is a hypertensive disorder related to placental dysfunction, characterized by an angiogenic imbalance between sFlt-1 and PlGF. It typically occurs after the 20^th week of pregnancy and can lead to serious complications for both the mother and baby if not managed properly. Prior to the introduction of the first preeclampsia biomarker test, risk stratification relied mainly on clinical symptoms and basic laboratory tests. This often resulted in delayed diagnosis and intervention or, alternatively, expedited labor and delivery and costly hospital stays due to a lack of definitive measures of risk.

Development of immunoassays for sFlt-1 and PlGF began in 2011. This effort culminated in the PRAECIS (Preeclampsia Risk Assessment: Evaluation of Cut-offs to Improve Stratification) study,³ the largest multicentric study done in the United States for this disease area. The study was published in November 2022, clearly demonstrating that in women with a hypertensive disorder of pregnancy presenting between 23 and 35 weeks of gestation, measurement of sFlt-1/PlGF ratio provided stratification of the risk of progressing to sPE within the coming two weeks as well as a strong association with adverse outcomes.

The evidence was there: the two biomarkers are biochemically associated with the disease and provide crucial information for the early identification and management of preeclampsia. In May 2023, Thermo Fisher’s sFlt-1/PlGF ratio became the first FDA-cleared biomarker test in the United States. With FDA Breakthrough Designation and clearance, this biomarker-based approach represented a significant advancement, opening doors for enhanced decision-making and patient-centric care for expectant mothers and their babies.

Adoption of biomarker-based care in the United States

Since its approval, biomarker-based risk assessment has been integrated into various healthcare settings across the U.S. Adoption rates, however, have varied, with some institutions leading the way in incorporating these tests into their standard prenatal care protocols.

One of the first adopters, The University of Chicago, began using the test on site in March 2024. Dr. Sarosh Rana, Professor of Obstetrics and Gynecology and Chief Obstetrical Transformation Officer at the university, led a study published in July of the same year cementing the first real-world evidence of the test’s validity.⁴ Study data from the first 65 samples confirmed earlier PRAECIS study results³ and shows the biomarker test helped to safely prolong pregnancies and prevent possible adverse outcomes. 

One particularly compelling story, the data of which was included in the study by The University of Chicago,⁴ is that of a patient with chronic hypertension hospitalized for elevated blood pressure measurements at home. She presented to labor and delivery at 31 weeks and 4 days gestation. The clinical evaluation outlined abnormal liver function, raising the concern of superimposed preeclampsia with severe features, requiring immediate delivery. Her measured sFlt-1/PlGF ratio, however, was found to be very low, indicating that the patient was at low risk of developing preeclampsia with severe features in the next two weeks. She was readmitted three weeks later, again with a low sFlt-1/PlGF ratio. With the support of personalized, biomarker-based care, in addition to standard clinical surveillance, this mother was able to prolong her pregnancy by seven weeks and delivered near full-term at week 38 weeks and 2 days. Without the test, it is likely she would have delivered during her first admission and her baby would have been highly premature.

Expanding access to improve patient outcomes

Preeclampsia affects 3-4% of all pregnancies in the United States and contributes largely to maternal and fetal morbidity and mortality.⁵ Early detection through biomarker testing definitively leads to timely intervention, reducing the incidence of severe complications associated with preeclampsia. It is therefore imperative that continued steps are taken to remove barriers that limit accessibility to, and widespread adoption of, biomarker-based preeclampsia testing.

The most recent study, published in early 2025,⁶ aimed to evaluate if the sFlt-1/PlGF ratio provides a neonatal cost benefit in the United States, drawing on recently published findings from the PRAECIS³ and real-world evidence⁴ studies. The research concludes that the sFlt-1/PlGF test, when used alongside standard care, enhances risk stratification for severe preeclampsia and may lead to significant neonatal cost savings by reducing preterm deliveries and neonatal intensive care admissions.

Indeed, an incremental cost-effectiveness ratio (ICER) calculation showed that prolonging pregnancy by two weeks, as a result of implementing biomarker-based care, led to a theoretical average cost savings of $62,572 per patient for the first six months of the baby’s life. These health economics data suggest that besides the significant clinical benefit, the test may impact positively the economic burden related to preeclampsia, helping support a case for broader adoption.

Paving the way for further advancements in prenatal care

Current research and development efforts are focused on improving patient outcomes through continued innovation in personalized prenatal care. The future of prenatal care is one in which the use of biomarkers has significantly improved the clinical management of preeclampsia, not just in times of crisis or concern, but also in screening from the first trimester of pregnancy on. There is still a lot of unmet need for pathology advancements in this area, as well as for other pregnancy complications such as gestational diabetes or preterm birth.

Conclusion

References 

1. Trends in maternal mortality 2000 to 2020: estimates by WHO, UNICEF, UNFPA, World Bank Group and UNDESA/Population Division. Who.int. February 23, 2023. Accessed February 28, 2025. https://www.who.int/publications/i/item/9789240068759. 
2. Thermo Fisher Scientific announces FDA clearance of breakthrough immunoassays to aid in the risk assessment of preeclampsia. Medical Laboratory Observer. May 22, 2023. Accessed February 28, 2025. https://www.mlo-online.com/diagnostics/article/53061210/thermo-fisher-scientific-announces-fda-clearance-of-breakthrough-immunoassays-to-aid-in-the-risk-assessment-of-preeclampsia. 
3. Thadhani R, Lemoine E, Rana S, et al. Circulating angiogenic factor levels in hypertensive disorders of pregnancy. NEJM Evid. 2022;1(12). doi:10.1056/evidoa2200161.
4. Burns LP, Potchileev S, Mueller A, et al. Real-world evidence for the utility of serum soluble fms-like tyrosine kinase 1/placental growth factor test for routine clinical evaluation of hospitalized women with hypertensive disorders of pregnancy. Am J Obstet Gynecol. Published online 2024. doi:10.1016/j.ajog.2024.07.015.
5. Burwick RM, Rodriguez MH. Angiogenic Biomarkers in Preeclampsia. Obstet Gynecol. 2024;143(4):515-523. doi:10.1097/AOG.0000000000005532.
6. Azzi M, Silasi M, Potchileev S, et al. Neonatal cost savings in hypertensive disorders of pregnancy: Economic evaluation of the sFlt-1/PlGF test with real world implementation of biomarkers. Pregnancy Hypertens. 2025;39(101190):101190. doi:10.1016/j.preghy.2025.101190.