Role of biomarkers in early detection of preeclampsia

Application of Proteomics in Maternal and Neonatal Health: Advancements and Future Directions

Maternal and neonatal health (women during pregnancy, childbirth, and the postnatal period) presents a spectrum of healthcare challenges, including preterm birth, preeclampsia, intrauterine growth restriction, polycystic ovarian syndrome, and gestational diabetes mellitus. While genomic investigations have shed light on many of these topics, protein biomarker discovery, a pivotal aspect of such research, holds promise in offering insights into disease diagnosis, progression, and prognosis. This review paper aims to explore the landscape of proteomics research pertaining to the aforementioned disorders. In the search for viable biomarkers, existing ones are either outdated or lack specificity and new ones being investigated do not commonly make it to the validation stage. In this review, the reasons for the gap between the biomarker discovery stage and the clinical validation stage are evaluated, in addition to what steps are being taken to mitigate the unexpectedly slow scientific and clinical progress. Notably, this paper also delves into the ethnic disparities found in maternal and neonatal health research, as well as how AI is currently being used to alleviate socioeconomic and ethnic disparities, as well as its advantages for the analysis of large "omics" datasets. We anticipate this investigation will provide critical, invaluable information for researchers, medical professionals, and policy decision-makers in this field to improve overall maternal and neonatal health outcomes.

Importance of STAT3 signaling in preeclampsia (Review)

Placentation is a key process that is tightly regulated that ensures the normal placenta and fetal development. Preeclampsia (PE) is a hypertensive pregnancy‑associated disorder characterized by increased oxidative stress and inflammation. STAT3 signaling plays a key role in modulating important processes such as cell proliferation, differentiation, invasion and apoptosis. The present review aimed to analyse the role of STAT3 signaling in PE pregnancies, discuss the main natural and synthetic compounds involved in modulation of this signaling both in vivo and in vitro and summarize the main cellular modulators of this signaling to identify possible therapeutic targets and treatments to improve the outcome of PE pregnancies.

Understanding the role of soluble proteins and exosomes in non-invasive urine-based diagnosis of preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy that can lead to stillbirth and preterm birth if not treated promptly. Currently, the diagnosis of preeclampsia relies on clinical symptoms such as hypertension and proteinuria, along with invasive blood tests. Here, we investigate the role of soluble proteins and exosomes in noninvasive diagnosing preeclampsia non-invasively using maternal urine and urine-derived exosomes. We quantified the levels of particles and the presence of TSG101 and CD63 in urine and urinary exosomes via the biologically intact exosome separation technology (BEST) platform. Then, we obtained higher levels of soluble proteins such as fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) from urine as it was than urinary exosomes. Compared to commercial blood tests, the sensitivity of the sFlt-1/PlGF ratio was found to be 4.0 times higher in urine tests and 1.5 times higher in tests utilizing urine-derived exosomes. Our findings offer promising possibilities for the early and non-invasive identification of high-risk individuals at risk of preeclampsia, allowing for comprehensive preventive management.

Identification of novel first-trimester serum biomarkers for early prediction of preeclampsia

BACKGROUND

Preeclampsia (PE) is a leading cause of maternal and perinatal mortality and morbidity worldwide, but effective early prediction remains a challenge due to the lack of reliable biomarkers.

METHODS

Based on the extensive human biobank of our large-scale assisted reproductive cohort platform, the first-trimester serum levels of 48 cytokines, total immunoglobulins (Igs), anti-phosphatidylserine (aPS) antibodies, and several previously reported PE biomarkers [including placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and activin A] were measured in 34 women diagnosed with PE and 34 matched normotensive controls.

RESULTS

The PE group has significantly higher first-trimester serum levels of interleukin (IL)-2Rα, IL-9, tumor necrosis factor-β (TNF-β), RANTES, hepatocyte growth factor (HGF), total IgM, and total IgG, and aPS IgG optical density (OD) value, as well as lower first-trimester serum levels of PlGF and total IgA and aPS-IgG immune complexes (IC) OD value than the control group. Combining top five first-trimester serum biomarkers (total IgM, total IgG, PlGF, aPS IgG, and total IgA) achieved superior predictive value [area under the curve (AUC) and 95% confidence interval (CI) 0.983 (0.952-1.000), with a sensitivity of 100% and a specificity of 94.1%] for PE development compared to PlGF and PlGF/sFlt-1 independently [AUC and 95% CI 0.825 (0.726-0.924) and 0.670 (0.539-0.800), respectively].

CONCLUSION

We identified novel first-trimester serum biomarkers and developed an effective first-trimester prediction model using immune-related factors and PlGF for PE, which could facilitate the development of early diagnostic strategies and provide immunological insight into the further mechanistic exploration of PE.

Maternal Serum Activin A, Inhibin A and Follistatin-Related Proteins across Preeclampsia: Insights into Their Role in Pathogenesis and Prediction

BACKGROUND

Within the endocrine-paracrine signalling network at the maternal-foetal interface, the activin-inhibin-follistatin system modulates extravillous trophoblast invasion, suggesting a potential role in preeclampsia pathogenesis. This study aimed to compile the evidence published in the last decade regarding the variation in maternal serum activins, inhibin- and follistatin-related proteins in preeclamptic pregnancies compared to healthy pregnancies, and to discuss their role in predicting and understanding the pathophysiology of preeclampsia.

MATERIAL AND METHODS

A scoping review was conducted in MEDLINE, EMBASE and LILACS databases to identify studies published within the last ten years (2012-2022).

RESULTS

Thirty studies were included. None of the studies addressed maternal serum changes of isoforms different from activin A, inhibin A, follistatin, and follistatin-like 3. Sixteen studies evaluated the potential of these isoforms in predicting preeclampsia through the area under the curve from a receiver operating characteristic curve.

CONCLUSIONS

In preeclampsia, inhibin A is upregulated in all trimesters, whereas activin A increases exclusively in the late second and third trimesters. Serum follistatin levels are reduced in women with preeclampsia during the late second and third trimesters. However, changes in follistatin-like 3 remain inconclusive. Inhibin A and activin A can potentially serve as biomarkers of early-onset preeclampsia based on the outcomes of the receiver operating characteristic curve analysis. Further investigations are encouraged to explore the feasibility of quantifying maternal serum levels of activin A and inhibin A as a clinical tool in early preeclampsia prediction.

Pregnancy, Preeclampsia, and COVID-19: Susceptibility and Mechanisms: A Review Study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters cells through angiotensin converting enzyme 2 (ACE2), which expression of its gene increases during pregnancy that is resulted in an enhanced level of the ACE2 enzyme. It might enhance the risk of SARS-CoV-2 infection and its complications in the pregnant women. Although, pregnancy hypertensive disorders and severe infection with SARS-CoV-2 are correlated with high comorbidity, these two entities should be discriminated from each other. Also, there is a concern about the risk of preeclampsia and consequently severe coronavirus disease 2019 (COVID-19) development in the pregnant women. So, to answer these questions, in the present review the literature was surveyed. It seems there is higher severity of COVID-19 among pregnant women than non-pregnant women and more adverse pregnancy outcomes among pregnant women infected with SARS-CoV-2. In addition, an association between COVID-19 with preeclampsia and the role of preeclampsia and gestational hypertension as risk factors for SARS-CoV-2 infection and its complications is suggested. However, infection of the placenta and the SARS-CoV-2 vertical transmission is rare. Various mechanisms could explain the role of COVID-19 in the risk of preeclampsia and association between preeclampsia and COVID-19. Suggested mechanisms are included decreased ACE2 activity and imbalance between Ang II and Ang-(1-7) in preeclampsia, association of both of severe forms of COVID-19 and pregnancy hypertensive disorders with comorbidity, and interaction between immune system, inflammatory cytokines and the renin angiotensin aldosterone system and its contribution to the hypertension pathogenesis. It is concluded that preeclampsia and gestational hypertension might be risk factors for SARS-CoV-2 infection and its complications.

Role of Vascular Endothelial Growth Factor (VEGF) in Human Embryo Implantation: Clinical Implications

Vascular endothelial growth factor (VEGF) is a well-known angiogenic factor that plays a critical role in various physiological and pathological processes. VEGF also contributes to the process of embryo implantation by enhancing embryo development, improving endometrial receptivity, and facilitating the interactions between the developing embryo and the endometrium. There is a correlation between the alteration of VEGF expression and reproductive failure, including recurrent implantation failure (RIF) and recurrent miscarriage (RM). In order to clarify the role of VEGF in embryo implantation, we reviewed recent literature concerning the expression and function of VEGF in the reproductive system around the time of embryo implantation and we provide a summary of the findings reported so far. We also explored the effects and the possible underlying mechanisms of action of VEGF in embryo implantation.

Maternal serum glycosylated fibronectin as a short-term predictor of preeclampsia: a prospective cohort study

Background

Preeclampsia is a major pregnancy complication that results in significant maternal and infant mortality, most of which occurs in low and middle-income countries. The accurate and timely diagnosis of preeclampsia is critical in management of affected pregnancies to reduce maternal and fetal/neonatal morbidity and mortality, yet difficulties remain in establishing the rigorous diagnosis of preeclampsia based on clinical parameters alone. Biomarkers that detect biochemical disease have been proposed as complements or alternatives to clinical criteria to improve diagnostic accuracy. This cohort study assessed the performance of several biomarkers, including glycosylated fibronectin (GlyFn), to rule-in or rule-out preeclampsia within 4 weeks in a cohort of women at increased risk for preeclampsia.

Methods

151 women with risk factors for or clinical signs and symptoms of preeclampsia were selected from a prospective cohort. Maternal serum samples were collected between 20 and 37 weeks of gestation. Clinical suspicion of preeclampsia was defined as presence of new-onset proteinuria, or clinical symptoms of preeclampsia. Subjects with a clinical diagnosis of preeclampsia at the time of enrollment were excluded. GlyFn, pregnancy-associated plasma protein-A2 (PAPPA2), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1) were measured by immunoassay. GlyFn was also determined using a rapid point-of care (POC) test format. Receiver-operating characteristic (ROC) curves derived from logistic regression analysis were used to determine the classification performance for each analyte.

Results

32 of 151 (21%) women developed a clinical diagnosis of preeclampsia within 4 weeks. All biomarkers exhibited good classification performance [GlyFn (area under the curve (AUROC) = 0.94, 91% sensitivity, 86% specificity); PAPPA2 AUC = 0.92, 87% sensitivity, 77% specificity; PlGF AUC = 0.90, 81% sensitivity, 83% specificity; sFlt-1 AUC = 0.92, 84% sensitivity, 91% specificity. The GlyFn immunoassay and the rapid POC test showed a correlation of r = 0.966.

Conclusions

In this prospective cohort, serum biomarkers of biochemical disease were effective in short-term prediction of preeclampsia, and the performance of GlyFn in particular as a POC test may meet the needs of rapid and accurate triage and intervention.

Evaluation of Serum Biomarkers and Other Diagnostic Modalities for Early Diagnosis of Preeclampsia

Objective: Preeclampsia (PE) is a multi-systemic complication of pregnancy often characterised with the onset of hypertension and proteinuria after 20 weeks of gestation. Today, PE is the leading cause of maternal and perinatal morbidity and mortality worldwide. An early detection of PE would allow a chance to plan the appropriate monitoring and for clinical management to be immediately done following early detection thus making prophylactic strategies much more effective. Materials and methods: This systematic review aims to evaluate the potential of the various serum biomarkers and diagnostic modalities (uterine artery Doppler, MAP, and maternal history) available for early prediction of PE with articles included and obtained through MEDLINE Full Text, Pubmed, Science Direct, ProQuest, SAGE, Taylor and Francis Online, Google Scholar, HighWire and Elsevier ClinicalKey. Results: Ninety-five articles were found that fulfilled all of our inclusion criteria. Placental growth factor (PlGF), pregnancy associated plasma protein A (PAPP-A), soluble fms-like tyrosine kinase (sFLT) and placental protein 13 (PP-13) were the most commonly studied biomarkers. Whereas uterine Doppler scanning and Mean Arterial Pressure (MAP) were the most commonly studied out of other modalities. Conclusion: Current evidence shows serum biomarkers such as PIGF, PP-13 and sFlt yielded the best results for a single biomarker with others having conflicting results. However, a combination model with other diagnostic modalities performed better than a single biomarker. In the future, new techniques will hopefully provide sets of multiple markers, which will lead to a screening program with clinically relevant performance. However further studies are required to improve current methods.

Assessment of preeclampsia risk by use of serum ionized magnesium-based equation

Background: Preeclampsia is a common medical complication in pregnancy. It has been reported to be associated with decreased serum magnesium levels. However, there has not been evidence demonstrating utilization of change in magnesium for prediction of preeclampsia. The purpose of this study was to develop magnesium fraction-based equations which took other significant clinical risk factors into consideration for prediction of preeclampsia.

Methods: We collected serum total and ionized magnesium ionized magnesium levels from 84 pregnant women diagnosed with preeclampsia after week 20 of pregnancy. The ionized magnesium fraction was then calculated by the percentage ratio of ionized and total magnesium level.

Results: Sixty-four (76.19%) women had normal pregnancy and 20 (23.81%) developed preeclampsia. The ionized magnesium fraction was significantly lower in preeclampsia group (23.95 ± 4.7% vs. 26.28 ± 2.3%, p = .04). Additionally, lower ionized magnesium fraction (24.67%), teenage and elderly primigravida were significantly associated with preeclampsia (OR = 4.41, 95% CI: 1.46–13.40, OR = 5.47, 95% CI: 1.85–35.42 and OR = 11.11, 95% CI: 1.09–113.78, respectively). Consequently, we attempted to develop ionized magnesium fraction-based equations calculate risk scores for preeclampsia. The area of ROC for predictive accuracy of the model was 0.77 (p < .001) and ROC suggested that the score of 0.27 would be a threshold for screening preeclampsia with 70% sensitivity and 81% specificity.

Conclusions: Ionized magnesium fraction may have been appropriate for screening of preeclampsia. We suggested blood testing on total and ionized magnesium concentrations as well as calculation of ionized magnesium fraction in addition to routine antenatal care for better screening of the disease.

Preeclampsia: Novel Mechanisms and Potential Therapeutic Approaches

Preeclampsia is a serious complication of pregnancy where it affects 5–8% of all pregnancies. It increases the morbidity and mortality of both the fetus and pregnant woman, especially in developing countries. It deleteriously affects several vital organs, including the kidneys, liver, brain, and lung. Although, the pathogenesis of preeclampsia has not yet been fully understood, growing evidence suggests that aberrations in the angiogenic factors levels and coagulopathy are responsible for the clinical manifestations of the disease. The common nominator of tissue damage of all these target organs is endothelial injury, which impedes their normal function. At the renal level, glomerular endothelial injury leads to the development of maternal proteinuria. Actually, peripheral vasoconstriction secondary to maternal systemic inflammation and endothelial cell activation is sufficient for the development of preeclampsia-induced hypertension. Similarly, preeclampsia can cause hepatic and neurologic dysfunction due to vascular damage and/or hypertension. Obviously, preeclampsia adversely affects various organs, however it is not yet clear whether pre-eclampsia per se adversely affects various organs or whether it exposes underlying genetic predispositions to cardiovascular disease that manifest in later life. The current review summarizes recent development in the pathogenesis of preeclampsia with special focus on novel diagnostic biomarkers and their relevance to potential therapeutic options for this disease state. Specifically, the review highlights the renal manifestations of the disease with emphasis on the involvement of angiogenic factors in vascular injury and on how restoration of the angiogenic balance affects renal and cardiovascular outcome of Preeclamptic women.

Evaluation of serum biomarkers for detection of preeclampsia severity in pregnant women

Objectives

To determine serum biomarkers in detection of preeclampsia severity among pregnant women.

Methods

Among 450 pregnant women with various severity of preeclampsia, serum biomarkers ofaspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), hemoglobin (Hb), platelet count (PLT), uric acid, direct bilirubin, total bilirubin, creatinine, and alkaline phosphatase were compared using area under the Receiver operating characteristic (ROC) curve and Area Under the Curve (AUC).

Results

The mean age of women was 30.63±6.43 years and with mean gestational age of 34.69±3.97 weeks. The mean level of LDH, ALT, uric acid, and creatinine were significantly higher in the women with severe type of preeclampsia compared to those with mild type. LDH level had ROC and AUC of more than 0.80, with highest sensitivity, and moderatespecificityin comparison to other markers.

Conclusion

Biomarkers such as ALT, uric acid, and LDH were shown to be prognostic in detection of theseverity of preeclampsia. LDH was demonstrated to significantly be a better prognostic test in detection of preeclampsia severity.

Reference intervals and longitudinal changes in copeptin and MR-proADM concentrations during pregnancy

Background:

Vasopressin and adrenomedullin and their stable by-products copeptin and midregional part of proadrenomedullin (MR-proADM) are promising biomarkers for the development of preeclampsia. However, clinical use is hampered by the lack of trimester-specific reference intervals. We therefore estimated reference intervals for copeptin and MR-proADM in disease-free Dutch women throughout pregnancy.

Methods:

Apparently healthy low risk pregnant women were recruited. Exclusion criteria included current or past history of endocrine disease, multiple pregnancy, use of medication known to influence thyroid function and current pregnancy as a result of hormonal stimulation. Women who miscarried, developed hyperemesis gravidarum, hypertension, pre-eclampsia, hemolysis elevated liver enzymes and low platelets, diabetes or other disease, delivered prematurely or had a small for gestational age neonate were excluded from analyses. Blood samples were collected at 9–13 weeks (n=98), 27–29 weeks (n=94) and 36–39 weeks (n=91) of gestation and at 4–13 weeks post-partum (PP) (n=89). Sixty-two women had complete data during pregnancy and PP. All analyses were performed on a Kryptor compact plus.

Results:

Copeptin increases during pregnancy, but 97.5th percentiles remain below the non-pregnant upper reference limit (URL) provided by the manufacturer. MR-proADM concentrations increase as well during pregnancy. In trimesters 2 and 3 the 97.5th percentiles are over three times the non-pregnant URL provided by the manufacturer.

Conclusions:

Trimester- and assay-specific reference intervals for copeptin and MR-proADM should be used. In addition, consecutive measurements and the time frame between measurements should be considered as the differences seen with or in advance of preeclampsia can be expected to be relatively small compared to the reference intervals.

Accuracy of Soluble Endoglin for Diagnosis of Preeclampsia and its Severity

Background

The use of biomarkers for diagnosis of Preeclampsia (PE), a life-threatening pregnancy disorder, could reduce serious complications of this disease. In this study, we investigated dysregulation of endoglin (Eng) expression and diagnostic accuracy of soluble endoglin (sEng) in PE patients.

Methods

For this case-control study, 26 mild and 15 severe preeclamptic women along with 20 normotensive controls were recruited. The expression level of Eng (the co-receptor of TGF-β1) was evaluated using qRT-PCR. Also, the serum concentration of soluble Eng and expression of membranous Eng were determined by ELISA and immunohistochemistry.

Results

A significant up-regulation in Eng mRNA and sEng levels was observed in PE patients versus normal controls. Immunohistochemistry (IHC) showed up-regulation of membranous Eng staining in syncytiotrophoblast and cytotrophoblast cells of PE patients. The serum levels of sEng were significantly increased in all patients (mild, sever, early- and late-onset) as compared to healthy pregnant women (P˂0.001). Receiver-operating characteristic (ROC) curve analysis revealed that sEng had the highest accuracy in distinguishing PE from normal pregnancies with cut-off value of 20.4, sensitivity of 92.1%, specificity of 90%, and area under the curve (AUC) of 0.94 (95% CI: 0.88-1.00).

Conclusion

Our data showed that the up-regulation of Eng mRNA along with its membranous and soluble form in PE patients leads to defect in angiogenesis pathway. Also, the results of this study revealed sEng potential as a marker for diagnosis of PE and its severity.

Expression of placental growth factor mRNA in preeclampsia

BACKGROUND

Preeclampsia (PE) is a serious complication of pregnancy with hallmarks of incomplete placentation, placental ischemia and endothelial dysfunction. Imbalance between vascular endothelial growth factor (VEGF), placenta growth factor (PlGF) and their receptors play important role in pathophysiology of PE.

OBJECTIVE

This study was aimed to asses PlGF mRNA expression in placenta of women affected with PE.

MATERIAL AND METHODS

In this cross-sectional study, expression of PlGF mRNA was evaluated in 26 mild PE cases, 15 severe preeclamptic women and 20 normotensive controls. Patients were sub-classified as early onset PE (9) and late onset (32). After RNA extraction, PlGF expression was quantified with qRT-PCR.

RESULTS

The results of PlGF mRNA expression between mild-severe, and early-late onset PE patients showed no statistically significant difference compared with the control group (p=0.661, p=0.205 respectively).

CONCLUSION

Despite we found no distinct differential expression of PlGF mRNA in placental tissue of PE patients compared with control women, but according to decreased level of this angiogenic factor in PE even before clinical onset of the disease, determining molecular mechanisms related to reduced secretion of PlGF into the maternal circulation may be useful for future therapeutics.

Usefulness of a biomarker to identify placental dysfunction in the context of malaria

In most tropical areas, pregnant women are at increased risk of malaria, as a consequence of the massive sequestration of parasitized red blood cells in the placenta. The placenta plays a key role in embryonic and fetal development as well as in maternal-fetal exchanges, and pregnancy-associated malaria may alter selected placenta functions that lead to stillbirth and low birth weight. Although there are several tools (blood smear examination, RDT, PCR) to diagnose malaria infection during pregnancy, there is currently no test to assess placenta dysfunction in the framework of pregnancy-associated malaria. Pregnancy-associated malaria shares many features with preeclampsia, an extensively studied disease. Various biomarkers associated with placental dysfunction have been identified as associated with preeclampsia. Several of these are inflammatory markers that lack of specificity. A few seem more specific of placenta dysfunction, including s-endoglin and sFlt1, increased in the peripheral blood during preeclampsia. The predictive value of these biomarkers should be studied in the context of pregnancy-associated malaria to evaluate their usefulness in identifying placental dysfunction during malaria. These biomarkers should be considered to improve the diagnosis of placental dysfunction during malaria and pregnant women monitoring.

Combined Screening for Early Detection of Pre-Eclampsia

Although the precise pathophysiology of pre-eclampsia remains unknown, this condition continues to be a major cause of maternal and fetal mortality. Early prediction of pre-eclampsia would allow for timely initiation of preventive therapy. A combination of biophysical and biochemical markers are superior to other tests for early prediction of the development of pre-eclampsia. Apart from the use of parameters in first-trimester aneuploidy screening, cell-free fetal DNA quantification is emerging as a promising marker for prediction of pre-eclampsia. This article reviews the current research of the most important strategies for prediction of pre-eclampsia, including the use of maternal risk factors, mean maternal arterial pressure, ultrasound parameters, and biomarkers.

The imbalance in expression of angiogenic and anti-angiogenic factors as candidate predictive biomarker in preeclampsia

Preeclampsia is an important pregnancy disorder with serious maternal and fetal complications which its etiology has not been completely understood yet. Early diagnosis and management of disease could reduce its potential side effects. The vascular endothelial growth factor (VEGF) family including VEGF-A is the most potent endothelial growth factor which induces angiogenesis and endothelial cell proliferation and has basic role in vasculogenesis. VEGF and its tyrosine kinase receptors (Flt1 and KDR) are major factors for fetal and placental angiogenic development. Finding mechanisms involved in expression of angiogenic factors may lead to new prognostic and therapeutic points in management of preeclampsia. Recent researches, has shown capability of some anti-angiogenic factors as potential candidate to be used as early predictors for preeclampsia. Soluble fms-like tyrosin kinase-1 (sFlt1) is a truncated splice variant of the membrane-bound VEGF receptor Flt1, that is produced by the placenta and it can bind to angiogenic growth factors and neutraliz, their effects. It is also observed that the ratio of sFlt1 to placental growth factor is valuable as prognostic marker. In this review, VEGF family member's role in angiogenesis is evaluated as biomarkers to be used for prediction of preeclampsia.

Diagnostic accuracy of the soluble Fms-like tyrosine kinase-1/placental growth factor ratio for preeclampsia: a meta-analysis based on 20 studies

PURPOSE

To investigate the accuracy of the soluble fms-like tyrosine kinase-1(sFlt-1)/placental growth factor (PlGF) ratio to predict preeclampsia (PE).

METHODS

A search in the PubMed, Embase, and Cochrane Library was conducted for human studies without language restriction. We included the studies reported sufficient data to reconstruct the diagnostic 2 × 2 table of sFlt-1/PlGF with testing of PlGF and sFlt-1 in serum or plasma. Two reviewers independently screened the articles. Disagreements were resolved by a third reviewer. Unpublished data were requested from the authors of the study by email.

RESULTS

Twenty studies with 28 groups of women with different gestational ages were included in our study. The pooled diagnostic sensitivity and specificity of sFlt-1/PlGF were 0.78 and 0.84 with the area under the SROC curve (AUC) of 0.88. In subgroup analyses, the diagnostic value of sFlt-1/PlGF for early-onset PE is highest with a pooled diagnostic odds ratio (DOR) of 241 and AUC of 0.98.

CONCLUSIONS

The accuracy of sFlt-1/PlGF ratio for screening PE was moderate and was high for early-onset PE. High-quality studies are needed to confirm their usefulness in prediction of PE in clinical practice.