Screening models using multiple markers for early detection of late-onset preeclampsia in low-risk pregnancy

Preeclampsia and its prediction: traditional versus contemporary predictive methods

OBJECTIVE

Preeclampsia (PE) poses a significant threat to maternal and perinatal health, so its early prediction, prevention, and management are of paramount importance to mitigate adverse pregnancy outcomes. This article provides a brief review spanning epidemiology, etiology, pathophysiology, and risk factors associated with PE, mainly discussing the emerging role of Artificial Intelligence (AI) deep learning (DL) technology in predicting PE, to advance the understanding of PE and foster the clinical application of early prediction methods.

METHODS

Our narrative review comprehensively examines the PE epidemiology, etiology, pathophysiology, risk factors and predictive approaches, including traditional models and AI deep learning technology.

RESULTS

Preeclampsia involves a wide range of biological and biochemical risk factors, among which poor uterine artery remodeling, excessive immune response, endothelial dysfunction, and imbalanced angiogenesis play important roles. Traditional PE prediction models exhibit significant limitations in sensitivity and specificity, particularly in predicting late-onset PE, with detection rates ranging from only 30% to 50%. AI models have exhibited a notable level of predictive accuracy and value across various populations and datasets, achieving detection rates of approximately 70%. Particularly, they have shown superior predictive capabilities for late-onset PE, thereby presenting novel opportunities for early screening and management of the condition.

CONCLUSION

AI DL technology holds promise in revolutionizing the prediction and management of PE. AI-based approaches offer a pathway toward more effective risk assessment methods by addressing the shortcomings of traditional prediction models. Ongoing research efforts should focus on expanding databases and validating the performance of AI in diverse populations, leading to the development of more sophisticated prediction models with improved accuracy.

The association between human chorionic gonadotropin and adverse pregnancy outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the association between human chorionic gonadotropin and adverse pregnancy outcomes.

DATA SOURCES

Medline, Embase, PubMed, and Cochrane were searched in November 2021 using Medical Subject Headings (MeSH) and relevant key words.

STUDY ELIGIBILITY CRITERIA

This analysis included published full-text studies of pregnant women with serum human chorionic gonadotropin testing between 8 and 28 weeks of gestation, investigating fetal outcomes (fetal death in utero, small for gestational age, preterm birth) or maternal factors (hypertension in pregnancy: preeclampsia, pregnancy-induced hypertension, placental abruption, HELLP syndrome, gestational diabetes mellitus).

METHODS

Studies were extracted using REDCap software. The Newcastle-Ottawa scale was used to assess for risk of bias. Final meta-analyses underwent further quality assessment using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) method.

RESULTS

A total of 185 studies were included in the final review, including the outcomes of fetal death in utero (45), small for gestational age (79), preterm delivery (62), hypertension in pregnancy (107), gestational diabetes mellitus (29), placental abruption (17), and HELLP syndrome (2). Data were analyzed separately on the basis of categorical measurement of human chorionic gonadotropin and human chorionic gonadotropin measured on a continuous scale. Eligible studies underwent meta-analysis to generate a pooled odds ratio (categorical human chorionic gonadotropin level) or difference in medians (human chorionic gonadotropin continuous scale) between outcome groups. First-trimester low human chorionic gonadotropin levels were associated with preeclampsia and fetal death in utero, whereas high human chorionic gonadotropin levels were associated with preeclampsia. Second-trimester high human chorionic gonadotropin levels were associated with fetal death in utero and preeclampsia.

CONCLUSION

Human chorionic gonadotropin levels are associated with placenta-mediated adverse pregnancy outcomes. Both high and low human chorionic gonadotropin levels in the first trimester of pregnancy can be early warning signs of adverse outcomes. Further analysis of human chorionic gonadotropin subtypes and pregnancy outcomes is required to determine the diagnostic utility of these findings in reference to specific cutoff values.

Lipid-based Nutritional Supplement Impact on Energy Intake, Appetite, Glucose and Insulin Levels in Under-Weight Pregnant and Lactating Women with Preeclampsia

OBJECTIVE

To investigate the response of nutritional supplement (LNS-PLW) on appetite score, energy intake, insulin and glucose levels in preeclamptic women.

DESIGN & PARTICIPANTS

Sixty under-weight preeclamptic primigravida were divided into two groups randomly and provided LNS-PLW/Placebo in the fasted state. Blood samples were collected at fasting state, after 30mins of supplementation, "ad libitum buffet" breakfast and lunch for glucose and insulin levels.

RESULTS

Total energy intake was higher significantly in the LNS-PLW group, although during breakfast it was significantly reduced. The insulin and glucose concentration was significantly increased after 30min of supplementation in the LNS-PLW group.

CONCLUSION

Intake of the LNS-PLW by pre-eclamptic women had short-term suppression on subsequent meal but improved total energy intake during trial.

Accuracy of placental growth factor alone or in combination with soluble fms-like tyrosine kinase-1 or maternal factors in detecting preeclampsia in asymptomatic women in the second and third trimesters: a systematic review and meta-analysis

OBJECTIVE

This study aimed to: (1) identify all relevant studies reporting on the diagnostic accuracy of maternal circulating placental growth factor) alone or as a ratio with soluble fms-like tyrosine kinase-1), and of placental growth factor-based models (placental growth factor combined with maternal factors±other biomarkers) in the second or third trimester to predict subsequent development of preeclampsia in asymptomatic women; (2) estimate a hierarchical summary receiver-operating characteristic curve for studies reporting on the same test but different thresholds, gestational ages, and populations; and (3) select the best method to screen for preeclampsia in asymptomatic women during the second and third trimester of pregnancy by comparing the diagnostic accuracy of each method.

DATA SOURCES

A systematic search was performed through MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform databases from January 1, 1985 to April 15, 2021.

STUDY ELIGIBILITY CRITERIA

Studies including asymptomatic singleton pregnant women at >18 weeks' gestation with risk of developing preeclampsia were evaluated. We included only cohort or cross-sectional test accuracy studies reporting on preeclampsia outcome, allowing tabulation of 2×2 tables, with follow-up available for >85%, and evaluating performance of placental growth factor alone, soluble fms-like tyrosine kinase-1- placental growth factor ratio, or placental growth factor-based models. The study protocol was registered on the International Prospective Register Of Systematic Reviews (CRD 42020162460).

METHODS

Because of considerable intra- and interstudy heterogeneity, we computed the hierarchical summary receiver-operating characteristic plots and derived diagnostic odds ratios, β, θi, and Λ for each method to compare performances. The quality of the included studies was evaluated by the QUADAS-2 tool.

RESULTS

The search identified 2028 citations, from which we selected 474 studies for detailed assessment of the full texts. Finally, 100 published studies met the eligibility criteria for qualitative and 32 for quantitative syntheses. Twenty-three studies reported on performance of placental growth factor testing for the prediction of preeclampsia in the second trimester, including 16 (with 27 entries) that reported on placental growth factor test alone, 9 (with 19 entries) that reported on the soluble fms-like tyrosine kinase-1-placental growth factor ratio, and 6 (16 entries) that reported on placental growth factor-based models. Fourteen studies reported on performance of placental growth factor testing for the prediction of preeclampsia in the third trimester, including 10 (with 18 entries) that reported on placental growth factor test alone, 8 (with 12 entries) that reported on soluble fms-like tyrosine kinase-1-placental growth factor ratio, and 7 (with 12 entries) that reported on placental growth factor-based models. For the second trimester, Placental growth factor-based models achieved the highest diagnostic odds ratio for the prediction of early preeclampsia in the total population compared with placental growth factor alone and soluble fms-like tyrosine kinase-1-placental growth factor ratio (placental growth factor-based models, 63.20; 95% confidence interval, 37.62-106.16 vs soluble fms-like tyrosine kinase-1-placental growth factor ratio, 6.96; 95% confidence interval, 1.76-27.61 vs placental growth factor alone, 5.62; 95% confidence interval, 3.04-10.38); placental growth factor-based models had higher diagnostic odds ratio than placental growth factor alone for the identification of any-onset preeclampsia in the unselected population (28.45; 95% confidence interval, 13.52-59.85 vs 7.09; 95% confidence interval, 3.74-13.41). For the third trimester, Placental growth factor-based models achieved prediction for any-onset preeclampsia that was significantly better than that of placental growth factor alone but similar to that of soluble fms-like tyrosine kinase-1-placental growth factor ratio (placental growth factor-based models, 27.12; 95% confidence interval, 21.67-33.94 vs placental growth factor alone, 10.31; 95% confidence interval, 7.41-14.35 vs soluble fms-like tyrosine kinase-1-placental growth factor ratio, 14.94; 95% confidence interval, 9.42-23.70).

CONCLUSION

Placental growth factor with maternal factors ± other biomarkers determined in the second trimester achieved the best predictive performance for early preeclampsia in the total population. However, in the third trimester, placental growth factor-based models had predictive performance for any-onset preeclampsia that was better than that of placental growth factor alone but similar to that of soluble fms-like tyrosine kinase-1-placental growth factor ratio. Through this meta-analysis, we have identified a large number of very heterogeneous studies. Therefore, there is an urgent need to develop standardized research using the same models that combine serum placental growth factor with maternal factors ± other biomarkers to accurately predict preeclampsia. Identification of patients at risk might be beneficial for intensive monitoring and timing delivery.

Effects of age on the diagnostic value of the soluble fms-like tyrosine kinase-1/ placental growth factor ratio in preeclampsia: a retrospective cohort study

OBJECTIVE

Measurement of the ratio between soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) supports the diagnosis of preeclampsia. sFlt-1/PlGF ratios of at least 85 and at least 110 have previously been suggested for diagnosis of early-onset and late-onset preeclampsia, respectively. However, angiogenic and antiangiogenic factors change throughout the process of aging, potentially influencing preeclampsia diagnosis. In this study, we therefore evaluated in detail the effect of maternal age on sFlt-1/PlGF ratios.

METHODS

A total of 2775 pregnant female patients were included in this retrospective cohort study, spread across three maternal age groups: 18-25 years, 26-35 years, and more than 35 years at delivery. Receiver-operating characteristic (ROC) curve analysis was employed to evaluate sFlt-1/PlGF ratio cutoffs for use in preeclampsia diagnosis.

RESULTS

Controls (2462 pregnant women) showed a significant difference in sFlt-1/PlGF ratios between the youngest and oldest age groups, which resulted in differences in the best-performing sFlt-1/PlGF ratio cutoffs: optimized cutoffs were 143.4 (52.9%, 98.2%), 8.6 (84.4%, 75.3%), and 22.9 (78.6%, 82.3%) in early-onset preeclampsia, and 46.4 (67.5%, 81.5%), 40.8 (77.3%, 73%), and 44.1 (65.1%, 74.5%) in late-onset preeclampsia in age groups, 1, 2, and 3, respectively.

CONCLUSION

sFlt-1/PlGF ratios change with maternal age, which has important clinical implications for their use in the diagnosis of preeclampsia: Better differentiated sFlt-1/PlGF cutoffs should be used that take maternal and gestational age into account.

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.

First trimester serum apolipoproteins in the prediction of late-onset preeclampsia

Late-onset preeclampsia occurring after 34 weeks of gestation is the most common form of preeclampsia, but little is known about either etiology or prevention. Current detection methods for preeclampsia in early pregnancy have not shown promising results in detecting late-onset preeclampsia. The aim of this study was to assess whether apolipoproteins in combination with maternal medical history and biophysical factors can be used as an early detection method for late-onset preeclampsia. This nested case-cohort study was based at Odense University Hospital, Denmark. Women attending their first trimester scan were invited to participate if they understood Danish or English, were above the age of 18, and had singleton pregnancies. Blood pressure, maternal medical history, uterine artery pulsatility indices, and blood samples were collected at inclusion. Outcome data were collected from participants' medical files postpartum, and cases were selected when preeclampsia diagnostics were present. Serum samples were analyzed by targeted mass spectrometry using a biomarker panel consisting of 12 apolipoproteins. Logistic regression analyses were performed and finally receiver operating curves were completed. The cohort consisted of 27 cases and 194 normotensive controls, randomized from 340 eligible participants. Significant differences were found between the two groups' baseline characteristics but none of the apolipoproteins showed significant difference (p < 0.05). The ROC-curve combining maternal characteristics, mean arterial pressure and two apolipoproteins showed the best sensitivity of 55.5% at a 10% false-positive rate and an area under the curve of 0.873. In conclusion, apolipoproteins did not improve the detection of late-onset preeclampsia in a combined screening model.

Metabolomic analysis-identified 2-hydroxybutyric acid might be a key metabolite of severe preeclampsia

This study set out to determine the key metabolite changes underlying the pathophysiology of severe preeclampsia (PE) using metabolic analysis. We collected sera from 10 patients with severe PE and from 10 healthy pregnant women of the same trimester and analyzed them using liquid chromatography mass spectrometry. A total of 3,138 differential metabolites were screened, resulting in the identification of 124 differential metabolites. Kyoto encyclopedia of genes and genomes pathway analysis revealed that they were mainly enriched in the following metabolic pathways: central carbon metabolism in cancer; protein digestion and absorption; aminoacyl-transfer RNA biosynthesis; mineral absorption; alanine, aspartate, and glutamate metabolism; and prostate cancer. After analysis of 124 differential metabolites, 2-hydroxybutyric acid was found to be the most critical differential metabolite, and its use allowed the differentiation of women with severe PE from healthy pregnant women. In summary, our analysis revealed that 2-hydroxybutyric acid is a potential key metabolite for distinguishing severe PE from healthy controls and is also a marker for the early diagnosis of severe PE, thus allowing early intervention.

Prenatal diagnosis and molecular cytogenetic characterization of mosaic ring chromosome 21 associated with low PAPP-A and low PlGF in the first-trimester maternal serum screening

OBJECTIVE

We present diagnosis and molecular cytogenetic characterization of mosaic ring chromosome 21 [r(21)].

CASE REPORT

A 17-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of an abnormal result of the first-trimester maternal serum screening for Down syndrome with a free β-hCG level of 1.736 multiples of the median (MoM), a pregnancy associated plasma protein-A (PAPP-A) level of 0.275 MoM, a placental growth factor (PlGF) level of 0.281 MoM, a Down syndrome risk of 1:222 and a preeclampsia risk of 1:175. Cytogenetic analysis of cultured amniocytes revealed the result of 46,XX,r(21) (p12q22.3)[19]/45,XX,-21[13]. Array comparative genomic hybridization (aCGH) analysis of cultured amniocytes revealed the result of arr [GRCh37] 21q11.2q22.2 (15,485,008-40,625,594) × 1∼2, 21q22.2q22.3 (40,703,792-46,682,184) × 2∼3, 21q22.3 (46,761,631-48,084,156) × 1, consistent with mosaic monosomy 21 and r(21) (p12q22.3). The pregnancy was subsequently terminated, and a malformed fetus was delivered with low-set ears and hypotelorism. Postnatal cytogenetic analysis revealed a karyotype of 46,XX,r(21) (p12q22.3)[30]/45,XX,-21[8]/46,XX,idic r(21) (p12q22.3)[2] in the cord blood, 46,XX,r(21) (p12q22.3)[34]/45,XX,-21[6] in the skin, 46,XX,r(21) (p12q22.3)[37]/45,XX,-21[3] in the umbilical cord and 46,XX,dup(21) (q22.2q22.3)[32]/46,XX,r(21) (p12q22.3)[8] in the placenta. aCGH analysis of cord blood revealed the result of arr 21q11.2q22.2 (15,499,847-40,662,581) × 2.3, arr 21q22.2q22.3 (40,703,792-46,682,184) × 3.6, arr 21q22.3 (46,761,632-48,090,317) × 1, consistent with mosaic duplication of 21q11.2-q22.2 and 21q22.2-q22.3, and a 1.33-Mb 21q22.3 deletion encompassing the genes of COL18A1, SLC19A1, PCBP3, COL6A1, COL6A2, FTCD, LSS, MCM3AP, YBEY, PCNT, DIP2A, S100B and PRMT2.

CONCLUSION

Mosaic r(21) at amniocentesis may be associated with monosomy 21, idic r(21) and dup(21), and low PAPP-A and low PlGF in the first-trimester maternal serum screening.

Upregulated pigment epithelium-derived factor (PEDF) promotes trophoblast apoptosis and inhibits invasion in preeclampsia

Preeclampsia (PE) is a severe pregnancy-specific disorder. Previous findings indicated that pigment epithelium-derived factor (PEDF) was upregulated in placentas of women with PE. Here, we investigated the role of PEDF in trophoblast function, especially under hypoxia. The effects of hypoxia on the morphology of extravillous trophoblast (EVT)-derived HTR-8Svneo cells were observed under inverted microscope. Transfections with Lipofectamine LTX were performed according to the manufacturer's protocol. The expression of PEDF protein and mRNA were confirmed by immunofluorescence (IF) and quantitative real-time PCR (qPCR). Apoptosis was detected by transferase-mediated dUTP nick end labeling (TUNEL) assay, and proliferation of trophoblast was detected by CCK-8 method. The invasion capacity of trophoblast was assessed by Transwell assay. PEDF was expressed in HTR-8/SVneo under both normoxia and hypoxic stress. However, cells of hypoxia groups had higher expression level of PEDF, increased apoptosis and decreased invasion capability, as compared with normoxia group. Moreover, after transfection with plasmid expressing PEDF gene, overexpression of PEDF modulated trophoblast activities. In addition, PEDF expression was negatively associated with invasion while positively correlated with apoptosis.Our data suggest that PEDF is an important factor to maintain the biological function of trophoblast cells, thus representing a rational therapeutic target in PE.

PAPP-A2 and Inhibin A as Novel Predictors for Pregnancy Complications in Women With Suspected or Confirmed Preeclampsia

Background We aimed to evaluate the value of inhibin A and PAPP-A2 (pregnancy-associated plasma protein-A2) as novel biomarkers in the prediction of preeclampsia-related complications and how they compare with angiogenic biomarkers. Methods and Results Making use of a secondary analysis of a prospective, multicenter, observational study, intended to evaluate the usefulness of sFlt-1 (soluble Fms-like tyrosine kinase-1)/PlGF (placental growth factor) ratio, we measured inhibin A and PAPP-A2 levels in 524 women with suspected/confirmed preeclampsia. Women had a median gestational age of 35 weeks (range, 20-41 weeks) while preeclampsia occurred in 170 (32%) women. Levels of inhibin A and PAPP-A2 were significantly increased in women with preeclampsia and in maternal perfusate of preeclamptic placentas. Inhibin A and PAPP-A2 (C-index = 0.73 and 0.75) significantly improved the prediction of maternal complications when added on top of the traditional criteria; gestational age, parity, proteinuria, and diastolic blood pressure (C-index = 0.60). PAPP-A2 was able to improve the C-index from 0.75 to 0.77 when added on top of the sFlt-1/PlGF ratio for the prediction of maternal complications. To discriminate fetal/neonatal complications on top of traditional criteria, inhibin A and PAPP-A2 showed additive value (C-index = 0.79 to 0.80 and 0.82, respectively) but their discriminative ability remained inferior to that of sFlt-1/PlGF ratio or PlGF. Interestingly, the PAPP-A2/PlGF ratio alone showed remarkable value to predict pregnancy complications, being superior to sFlt-1/PlGF ratio in the case of maternal complications. Conclusions Inhibin A and PAPP-A2 show significant potential to predict preeclampsia-related pregnancy complications and might prove beneficial on top of the angiogenic markers.

Diagnostic accuracy of sFlt1/PlGF ratio as a marker for preeclampsia

BACKGROUND

Preeclampsia (PE) is a serious complication of pregnancy and one of the main causes of maternal and neonatal mortality and morbidity in the world. Finding a biomarker with high sensitivity and specificity could lead to prediction and early diagnosis of the disease and reduces its complications. In this study, we evaluated diagnostic accuracy of Soluble fms-like tyrosine kinase-1 (sFlt-1) to Placental growth factor (PlGF) ratio for diagnosis of PE.

METHODS

The cases included 23 mild, 15 severe preeclamptic patients, and 20 normal term pregnant women as control referred to GYN ward of the Persian Gulf Hospital in Bandar Abbas from 2014 to 2016. Levels of sFlt-1 and PlGF were measured. Receiver Operating Characteristic (ROC) curve analysis was applied to calculate diagnostic accuracy of sFlt-1/PlGF ratio.

RESULTS

The mean Level of sFlt-1/PlGF in PE patients (91.33 ng/ml) was significantly higher than control women (17.62) (P<0.001). ROC curve analysis showed sFlt-1/PlGF ratio diagnostic accuracy in preeclamptic patients with Area Under Curve (AUC) of 0.90, the best cut-off value of 24.96, sensitivity and specificity of 84.2 and 85.0%, respectively.

CONCLUSIONS

Our data showed sFlt-1/PlGF ratio has higher accuracy for differentiating PE patients from non-PEs in comparison with its power for differentiating severe or early onset forms of the disease.

A preeclampsia risk prediction model based on maternal characteristics and serum markers in twin pregnancy

Aim: To develop preeclampsia (PE) risk prediction model based on maternal characteristics and serum markers at the first and second trimester in the twin pregnancy.Methods: Between January 2005 and September 2017, we retrospectively reviewed medical records of 532 twin pregnant women who underwent maternal serum integrated test and gave birth at a Bundang CHA Medical Center. Maternal serum pregnancy-associated plasma protein A (PAPP-A) was determined at 10⁺⁰ to 13⁺⁶ weeks and the serum alpha-fetoprotein (MSAFP), human chorionic gonadotrophin (hCG), unconjugated estriol (uE₃) and inhibin A were assayed at 14⁺⁰ to 22⁺⁰weeks. We assessed the relationships of maternal characteristics and serum markers by using multiple logistic regression analysis.Results: The study included 35 patients who diagnosed PE and a control group consisting of the other 497 patients in twin pregnancy. There were no significant differences in the maternal age and body mass index (BMI) between two groups. However, the gestational age and placenta weight at delivery were significantly different between groups (p < .001, p = .005, respectively. Among the maternal serum markers, inhibin A value was significantly higher in women with PE compared to those without preeclampsia (p < .001). In addition, we predicted the PE using maternal age, BMI, uE₃, and inhibin A which were achieving an area under the curve of 0.73 overall in twin pregnancy.Conclusion: A risk prediction model of PE which combined maternal age, BMI, uE₃, and inhibin A was better early predictors than any individual marker twin pregnancy.

Biosensors for Detection of Human Placental Pathologies: A Review of Emerging Technologies and Current Trends

Substantial growth in the biosensor research has enabled novel, sensitive and point-of-care diagnosis of human diseases in the last decade. This paper presents an overview of the research in the field of biosensors that can potentially predict and diagnosis of common placental pathologies. A survey of biomarkers in maternal circulation and their characterization methods is presented, including markers of oxidative stress, angiogenic factors, placental debris, and inflammatory biomarkers that are associated with various pathophysiological processes in the context of pregnancy complications. Novel biosensors enabled by microfluidics technology and nanomaterials is then reviewed. Representative designs of plasmonic and electrochemical biosensors for highly sensitive and multiplexed detection of biomarkers, as well as on-chip sample preparation and sensing for automatic biomarker detection are illustrated. New trends in organ-on-a-chip based placental disease models are highlighted to illustrate the capability of these in vitro disease models in better understanding the complex pathophysiological processes, including mass transfer across the placental barrier, oxidative stress, inflammation, and malaria infection. Biosensor technologies that can be potentially embedded in the placental models for real time, label-free monitoring of these processes and events are suggested. Merger of cell culture in microfluidics and biosensing can provide significant potential for new developments in advanced placental models, and tools for diagnosis, drug screening and efficacy testing.

Predictive Performance of PlGF (Placental Growth Factor) for Screening Preeclampsia in Asymptomatic Women: A Systematic Review and Meta-Analysis

Preeclampsia is a systemic syndrome that seems to originate from the placenta and is associated with an imbalance between angiogenic factors in the maternal circulation. One of the well-studied and widely used factors is PlGF (placental growth factor), the levels of which drop in women destined to develop preeclampsia. This drop is known to precede the development of actual signs and symptoms of preeclampsia, thus proving to be a useful screening tool in predicting the disease. The literature varies widely in terms of the clinical usefulness of the test. We conducted a meta-analysis to study the predictive accuracy of PlGF in asymptomatic women. Our analysis included 40 studies with 3189 cases of preeclampsia and 89 498 controls. The overall predictive odds ratio of the test was 9 (6-13). Subgroup analysis evaluating various PlGF thresholds demonstrated that the predictive values were highest for PlGF levels between 80 and 120 pg/mL with a high predictive odds ratio of 25 (7-88), a sensitivity of 0.78 (95% CI, 0.67-0.86), a specificity of 0.88 (95% CI, 0.75-0.95), a positive likelihood ratio of 6.3 (95% CI, 2.7-14.7), and a negative likelihood ratio of 0.26 (95% CI, 0.16-0.42). Additionally, the accuracy was higher when the test was performed after 14 weeks of gestation (OR, 10 [7-15]) and for prediction of early onset preeclampsia (OR, 18 [9-37]). We conclude that PlGF is a useful screening tool to predict preeclampsia. Nonetheless, its utility should be judged with caution and randomized controlled trials are warranted to explore if its implementation improves perinatal outcomes in asymptomatic women.

The prediction of early preeclampsia: Results from a longitudinal proteomics study

OBJECTIVES

To identify maternal plasma protein markers for early preeclampsia (delivery <34 weeks of gestation) and to determine whether the prediction performance is affected by disease severity and presence of placental lesions consistent with maternal vascular malperfusion (MVM) among cases.

STUDY DESIGN

This longitudinal case-control study included 90 patients with a normal pregnancy and 33 patients with early preeclampsia. Two to six maternal plasma samples were collected throughout gestation from each woman. The abundance of 1,125 proteins was measured using high-affinity aptamer-based proteomic assays, and data were modeled using linear mixed-effects models. After data transformation into multiples of the mean values for gestational age, parsimonious linear discriminant analysis risk models were fit for each gestational-age interval (8-16, 16.1-22, 22.1-28, 28.1-32 weeks). Proteomic profiles of early preeclampsia cases were also compared to those of a combined set of controls and late preeclampsia cases (n = 76) reported previously. Prediction performance was estimated via bootstrap.

RESULTS

We found that 1) multi-protein models at 16.1-22 weeks of gestation predicted early preeclampsia with a sensitivity of 71% at a false-positive rate (FPR) of 10%. High abundance of matrix metalloproteinase-7 and glycoprotein IIbIIIa complex were the most reliable predictors at this gestational age; 2) at 22.1-28 weeks of gestation, lower abundance of placental growth factor (PlGF) and vascular endothelial growth factor A, isoform 121 (VEGF-121), as well as elevated sialic acid binding immunoglobulin-like lectin 6 (siglec-6) and activin-A, were the best predictors of the subsequent development of early preeclampsia (81% sensitivity, FPR = 10%); 3) at 28.1-32 weeks of gestation, the sensitivity of multi-protein models was 85% (FPR = 10%) with the best predictors being activated leukocyte cell adhesion molecule, siglec-6, and VEGF-121; 4) the increase in siglec-6, activin-A, and VEGF-121 at 22.1-28 weeks of gestation differentiated women who subsequently developed early preeclampsia from those who had a normal pregnancy or developed late preeclampsia (sensitivity 77%, FPR = 10%); 5) the sensitivity of risk models was higher for early preeclampsia with placental MVM lesions than for the entire early preeclampsia group (90% versus 71% at 16.1-22 weeks; 87% versus 81% at 22.1-28 weeks; and 90% versus 85% at 28.1-32 weeks, all FPR = 10%); and 6) the sensitivity of prediction models was higher for severe early preeclampsia than for the entire early preeclampsia group (84% versus 71% at 16.1-22 weeks).

CONCLUSION

We have presented herein a catalogue of proteome changes in maternal plasma proteome that precede the diagnosis of preeclampsia and can distinguish among early and late phenotypes. The sensitivity of maternal plasma protein models for early preeclampsia is higher in women with underlying vascular placental disease and in those with a severe phenotype.

Maternal ABO Blood Type and Factors Associated With Preeclampsia Subtype

BACKGROUND

The pathophysiology of preeclampsia remains unclear. The disorder is heterogeneous, and the pathophysiology may vary by subtype. Identification of relevant biomarkers will help to better elucidate the pathophysiologic basis of each preeclampsia subtype. Blood type may be a biomarker that allows risk identification for preeclampsia.

OBJECTIVE

The purpose of this study was to investigate the associations among maternal ABO blood type and preeclampsia subtype and fetal growth restriction (FGR).

METHOD

Medical records of 126 women with early-onset preeclampsia (≤33 6/7 weeks' gestation), 126 women with late-onset preeclampsia (≥34 0/7 weeks' gestation), and 259 controls who gave birth between January 2012 and June 2016 were retrospectively abstracted from a large suburban tertiary referral center in South Central Pennsylvania for this hospital-based case-control study.

RESULTS

Women with AB blood type had >3 times the odds of late-onset preeclampsia (odds ratio [ OR] = 3.35, 95% confidence interval (CI) = [1.02, 11.05]) compared to those with O blood type. Among women with early-onset preeclampsia, those with B blood type had 5 times the odds of having a growth-restricted fetus than did women with O blood type ( OR = 5.44, 95% CI [1.65, 17.94]).

DISCUSSION

Our findings suggest that AB blood type may be an important risk factor for late-onset preeclampsia and that among women with early-onset preeclampsia, those with B blood type have increased odds of FGR. These findings warrant further study in women and their offspring to identify the pathophysiologic processes that may link ABO blood type, preeclampsia subtype, and FGR.

Predictive value of the sFlt-1 and PlGF in women at risk for preeclampsia in the south of Vietnam

BACKGROUND

It has been suggested that soluble fms-like tyrosine kinase receptor-1 (sFlt-1) and placental growth factor (PlGF) play potential roles in preeclampsia diagnosis. Nevertheless, studies on the use of sFlt-1, PlGF, and sFlt-1/PlGF ratio in predicting preeclampsia have found contradictory results. Thus, more studies in different populations are needed.

OBJECTIVES

This study aims to (i) examine the associations between sFlt-1, PlGF, or sFlt-1/PlGF ratio at gestational ages of 24-28 weeks and subsequent preeclampsia, and (ii) estimate predictive values of these markers in southern Vietnamese women.

METHODS

We used a nested case-control design from a cohort of 490 pregnant women who were at risk of preeclampsia. The total sample size for statistical analysis consisted of 30 cases and 67controls. Levels of sFlt-1 and PlGF were quantified by using a fully automated electrochemiluminescence immunoassay platform (Elecsys®/Cobas®).

RESULTS

The median of sFlt-1 concentration was not statistically different between case and control groups. The median PlGF concentration was lower (349.7 pg/ml versus 534.6 pg/ml, P < .001) and the median sFlt-1/PlGF ratio was higher in the preeclampsia group (4.3 versus 1.9, P < .001). After adjusting for maternal age, gestational age, nullipara, and body mass index, the odds of preeclampsia in women with an sFlt-1/PlGF ratio in the fourth quartile were 10 times greater than in women with an sFlt-1/PlGF ratio in the other quartiles (95% confidence interval, 3.2-31.4; P < .001).

CONCLUSIONS

This study contributes to the literature that sFlt-1/PlGF ratio measured at gestational weeks 24-28 in southern Vietnamese women can separate preeclamptic from normotensive cases.

Preeclampsia and the challenge of early prediction: reality or utopia? State of art and critical review of literature

Purpose: The challenge to obtain improved predictive tools, able to identify women destined to develop preeclampsia (PE), is raising the interest of researchers for the attractive chance to allow for timely initiation of prophylactic therapy, appropriate antenatal surveillance, and better-targeted research into preventive interventions. We aimed to gather all the evidence reported up to now in scientific literature relating to all prediction tests for PE.Materials and methods: We searched articles on conventional literature platforms from January 1952 to August 2016, using the terms "preeclampsia," "gestational preeclampsia," and "gestational hypertensive disorders" combined with "predictive test" and "risk assessment." Abstracts/titles identified by the search were screened by three investigators.Results: The search identified 203 citations, of which 154 potentially relevant after the initial evaluation. Among these studies, 20 full articles were excluded, therefore, 134 primary studies met the criteria for inclusion and were analyzed.Conclusions: Current evidence suggests that a combination of several features may provide the best predictive accuracy for the identification of PE. Large-scale, multicenter, multiethnic, prospective trials are required to propose an ideal combination of markers for routine screening.

Improved prediction of gestational hypertension by inclusion of placental growth factor and pregnancy associated plasma protein-a in a sample of Ghanaian women

BACKGROUND

We assessed whether adding the biomarkers Pregnancy Associated Plasma Protein-A (PAPP-A) and Placental Growth Factor (PlGF) to maternal clinical characteristics improved the prediction of a previously developed model for gestational hypertension in a cohort of Ghanaian pregnant women.

METHODS

This study was nested in a prospective cohort of 1010 pregnant women attending antenatal clinics in two public hospitals in Accra, Ghana. Pregnant women who were normotensive, at a gestational age at recruitment of between 8 and 13 weeks and provided a blood sample for biomarker analysis were eligible for inclusion. From serum, biomarkers PAPP-A and PlGF concentrations were measured by the AutoDELFIA immunoassay method and multiple of the median (MoM) values corrected for gestational age (PAPP-A and PlGF) and maternal weight (PAPP-A) were calculated. To obtain prediction models, these biomarkers were included with clinical predictors maternal weight, height, diastolic blood pressure, a previous history of gestational hypertension, history of hypertension in parents and parity in a logistic regression to obtain prediction models. The Area Under the Receiver Operating Characteristic Curve (AUC) was used to assess the predictive ability of the models.

RESULTS

Three hundred and seventy three women participated in this study. The area under the curve (AUC) of the model with only maternal clinical characteristics was 0.75 (0.64-0.86) and 0.89(0.73-1.00) for multiparous and primigravid women respectively. The AUCs after inclusion of both PAPP-A and PlGF were 0.82 (0.74-0.89) and 0.95 (0.87-1.00) for multiparous and primigravid women respectively.

CONCLUSION

Adding the biomarkers PAPP-A and PlGF to maternal characteristics to a prediction model for gestational hypertension in a cohort of Ghanaian pregnant women improved predictive ability. Further research using larger sample sizes in similar settings to validate these findings is recommended.

Placental growth factor (alone or in combination with soluble fms-like tyrosine kinase 1) as an aid to the assessment of women with suspected pre-eclampsia: systematic review and economic analysis

BACKGROUND

Pre-eclampsia (PE) prediction based on blood pressure, presence of protein in the urine, symptoms and laboratory test abnormalities can result in false-positive diagnoses. This may lead to unnecessary antenatal admissions and preterm delivery. Blood tests that measure placental growth factor (PlGF) or the ratio of soluble fms-like tyrosine kinase 1 (sFlt-1) to PlGF could aid prediction of PE if either were added to routine clinical assessment or used as a replacement for proteinuria testing.

OBJECTIVES

To evaluate the diagnostic accuracy and cost-effectiveness of PlGF-based tests for patients referred to secondary care with suspected PE in weeks 20-37 of pregnancy.

DESIGN

Systematic reviews and an economic analysis.

DATA SOURCES

Bibliographic databases including MEDLINE, EMBASE, Web of Science and The Cochrane Library and Database of Abstracts of Reviews of Effects were searched up to July 2015 for English-language references. Conferences, websites, systematic reviews and confidential company submissions were also accessed.

REVIEW METHODS

Systematic reviews of test accuracy and economic studies were conducted to inform an economic analysis. Test accuracy studies were required to include women with suspected PE and report quantitatively the accuracy of PlGF-based tests; their risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria. The economic studies review had broad eligibility criteria to capture any types of economic analysis; critical appraisal employed standard checklists consistent with National Institute for Health and Care Excellence criteria. Study selection, critical appraisal and data extraction in both reviews were performed by two reviewers.

ECONOMIC ANALYSIS

An independent economic analysis was conducted based on a decision tree model, using the best evidence available. The model evaluates costs (2014, GBP) from a NHS and Personal Social Services perspective. Given the short analysis time horizon, no discounting was undertaken.

RESULTS

Four studies were included in the systematic review of test accuracy: two on Alere's Triage^® PlGF test (Alere, Inc., San Diego, CA, USA) for predicting PE requiring delivery within a specified time and two on Roche Diagnostics' Elecsys^® sFlt-1 to PlGF ratio test (Roche Diagnostics GmbH, Mannheim, Germany) for predicting PE within a specified time. Three studies were included in the systematic review of economic studies, and two confidential company economic analyses were assessed separately. Study heterogeneity precluded meta-analyses of test accuracy or cost-analysis outcomes, so narrative syntheses were conducted to inform the independent economic model. The model predicts that, when supplementing routine clinical assessment for rule-out and rule-in of PE, the two tests would be cost-saving in weeks 20-35 of gestation, and marginally cost-saving in weeks 35-37, but with minuscule impact on quality of life. Length of neonatal intensive care unit stay was the most influential parameter in sensitivity analyses. All other sensitivity analyses had negligible effects on results.

LIMITATIONS

No head-to-head comparisons of the tests were identified. No studies investigated accuracy of PlGF-based tests when used as a replacement for proteinuria testing. Test accuracy studies were found to be at high risk of clinical review bias.

CONCLUSIONS

The Triage and Elecsys tests would save money if added to routine clinical assessment for PE. The magnitude of savings is uncertain, but the tests remain cost-saving under worst-case assumptions. Further research is required to clarify how the test results would be interpreted and applied in clinical practice.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015017670.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

A best practice position statement on the role of the nephrologist in the prevention and follow-up of preeclampsia: the Italian study group on kidney and pregnancy

Preeclampsia (PE) is a protean syndrome causing a transitory kidney disease, characterised by hypertension and proteinuria, ultimately reversible after delivery. Its prevalence is variously estimated, from 3 to 5% to 10% if all the related disorders, including also pregnancy-induced hypertension (PIH) and HELLP syndrome (haemolysis, increase in liver enzyme, low platelets) are included. Both nephrologists and obstetricians are involved in the management of the disease, according to different protocols, and the clinical management, as well as the role for each specialty, differs worldwide. The increased awareness of the role of chronic kidney disease in pregnancy, complicating up to 3% of pregnancies, and the knowledge that PE is associated with an increased risk for development of CKD later in life have recently increased the interest and redesigned the role of the nephrologists in this context. However, while the heterogeneous definitions of PE, its recent reclassification, an emerging role for biochemical biomarkers, the growing body of epidemiological data and the new potential therapeutic interventions lead to counsel long-term follow-up, the lack of resources for chronic patients and the increasing costs of care limit the potential for preventive actions, and suggest tailoring specific interventional strategies. The aim of the present position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature and to try to identify theoretical and pragmatic bases for an agreed management of PE in the nephrological setting, with particular attention to the prevention of the syndrome (recurrent PE, presence of baseline CKD) and to the organization of the postpartum follow-up.

Lower placental growth factor and higher free β-hCG and PAPP-A levels in the fetal circulation of near-term pregnancies complicated with severe preeclampsia

BACKGROUND

An imbalance between anti- and angiogenic factors during early placentation is key for the development of preeclampsia. Nevertheless, the majority of studies addressing this issue relate to maternal blood and not the fetal circulation.

OBJECTIVE

To measure placental growth factor (PlGF), free beta human chorionic gonadotropin (β-hCG), and pregnancy-associated plasma protein-A (PAPP-A) levels in the fetal circulation of near-term pregnancies complicated with severe preeclampsia (n = 20), and their controls matched for parity, and maternal and gestational age.

METHOD

Upon delivery, a blood sample was withdrawn from the umbilical artery and vein of each case and its control in order to measure the proposed analytes using direct fluoroimmunoassay.

RESULTS

Preeclampsia cases showed significantly lower median PlGF levels in fetal circulation as compared to controls (25.2 versus 36.9 and 23.6 versus 33.9 pg/mL, artery and vein, respectively, p < 0.05). Contrarily, cases displayed higher concentrations of PAPP-A (1024.0 versus 720.9 [median] and 1027.0 ± 298.4 versus 690.3 ± 401.9 mIU/L, artery and vein, respectively, p < 0.05), and free β-hCG (mean: 33.9 ± 4.3 versus 17.2 ± 4.0 and 30.1 ± 5.2 versus 13.7 ± 3.3 ng/mL, artery, and vein respectively, p < 0.05).

CONCLUSION

Lower PlGF and higher PAPP-A and free β-hCG levels were found in the fetal circulation of near-term severe preeclamptic pregnancies. There is a need for more research in this regard.

Diagnosis of pre-eclampsia and assessment of severity through examination of the placenta with acoustic radiation force impulse elastography

OBJECTIVE

To assess the value of placental shear wave velocity (SWV) measurement by acoustic radiation force impulse (ARFI) imaging for the diagnosis of pre-eclampsia and to determine the relationship between the SWV and the severity of pre-eclampsia.

METHODS

A prospective study was performed at a center in Turkey between August 2014 and March 2015. The study included consecutive pregnant women in the second or third trimester diagnosed with pre-eclampsia and healthy pregnant women without pre-eclampsia of similar ages. Patients with pre-eclampsia were divided into two groups (severe or mild disease) on the basis of revised American College of Obstetricians and Gynecologists criteria. All patients underwent ARFI, and the SWV was measured at several placental locations.

RESULTS

Overall, 86 women were enrolled (42 with pre-eclampsia, 44 controls). Minimum, maximum, and mean SWV values were significantly higher in the pre-eclampsia group than in the control group (P<0.001 for all). These values were also significantly higher among patients with severe pre-eclampsia than among patients with mild pre-eclampsia (P<0.001 for all).

CONCLUSION

Measurement of the placental SWV with ARFI imaging is a useful additional method for the diagnosis of pre-eclampsia and for determination of the disease severity.

A study of serum Apo A-1 and Apo B-100 levels in women with preeclampsia

OBJECTIVE

To investigate Apo A-1 and Apo B-100 levels and Apo B-100/Apo A-1 ratios in preeclamptic (PE) patients.

MATERIALS AND METHODS

Forty-eight PE and 48 without PE patients (healthy pregnancies) matched for gestational age were included. Maternal age, parity, gestational age at delivery, obstetrical complications including intrauterine growth restriction (IUGR) and gestational diabetes mellitus (GDM), serum Apo A-1 and Apo B-100 levels, and the Apo B-100/Apo A-1 ratio were compared.

RESULTS

Preeclamptic patients had significantly lower Apo A-1 levels (167.07mg/dl±14.61mg/dl vs. 244.37mg/dl±20.84mg/dl, p<0.001), higher Apo B-100/Apo A-1 ratio (0.63±0.07 vs. 0.42±0.05, p<0.001), but similar Apo B-100 levels (104.84mg/dl±7.05mg/dl vs. 102.39mg/dl±8.08mg/dl, p=0.118). Mean Apo A-1 and Apo B-100 levels and the Apo B-100/Apo A-1 ratio were similar in patients with severe PE, HELLP syndrome, IUGR, and patients requiring antihypertensive therapy compared to PE patients who did not have these complications (p>0.05). Apo A-1 levels had the best accuracy followed by the Apo B-100/Apo A-1 ratio in patients with PE.

CONCLUSION

Apo A-1 and the Apo B-100/Apo A-1 ratio may be useful markers in patients with PE. Further studies are required to elucidate this issue.

Early Pregnancy Biomarkers in Pre-Eclampsia: A Systematic Review and Meta-Analysis

Pre-eclampsia (PE) complicates 2%–8% of all pregnancies and is an important cause of perinatal morbidity and mortality worldwide. In order to reduce these complications and to develop possible treatment modalities, it is important to identify women at risk of developing PE. The use of biomarkers in early pregnancy would allow appropriate stratification into high and low risk pregnancies for the purpose of defining surveillance in pregnancy and to administer interventions. We used formal methods for a systematic review and meta-analyses to assess the accuracy of all biomarkers that have been evaluated so far during the first and early second trimester of pregnancy to predict PE. We found low predictive values using individual biomarkers which included a disintegrin and metalloprotease 12 (ADAM-12), inhibin-A, pregnancy associated plasma protein A (PAPP-A), placental growth factor (PlGF) and placental protein 13 (PP-13). The pooled sensitivity of all single biomarkers was 0.40 (95% CI 0.39–0.41) at a false positive rate of 10%. The area under the Summary of Receiver Operating Characteristics Curve (SROC) was 0.786 (SE 0.02). When a combination model was used, the predictive value improved to an area under the SROC of 0.893 (SE 0.03). In conclusion, although there are multiple potential biomarkers for PE their efficacy has been inconsistent and comparisons are difficult because of heterogeneity between different studies. Therefore, there is an urgent need for high quality, large-scale multicentre research in biomarkers for PE so that the best predictive marker(s) can be identified in order to improve the management of women destined to develop PE.

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.

Predictive accuracy of the first trimester Doppler scan: a meta-study

AIM

To determine sensitivity and cut-off indices of the uterine artery Doppler (UAD) in prediction of preeclampsia and fetal growth restriction (FGR).

METHODS

Seventy-six studies published in 1995-2014, present 298,329 prenatal Doppler screenings performed in nullipara in the first and early second trimesters of singleton pregnancies. The sample is stratified into four groups based on the Doppler sensitivity and specificity indices pertaining to the major clinical endpoints of the cohort.

RESULTS

The FGR diagnostic specificity (r = 0.728) and bilateral notching index (r = 0.803) correlations indicate that the UAD accuracy depends on the placental bed and the screening mode.

CONCLUSIONS

Predictive sensitivity of the UAD increases after 16 weeks + 3 days (115 days) of gestation. The best predictive parameter of preeclampsia and FGR is the placental side uterine artery resistance index which confers to the highest means when the placenta is on the midline (OR 0.9).

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.

Predictive biomarkers of pre-eclampsia and effectiveness of preventative interventions for the disease

INTRODUCTION

Pre-eclampsia (PE) is one of the most common pregnancy complication characterized by placental and maternal vascular dysfunction. It affects about 3 - 8% of women during the second half of pregnancy and represents one of the major causes of neonatal morbidity and mortality. The etiology of PE largely remains unknown.

AREAS COVERED

PE is considered a syndrome with multisystem involvement, so the ideal predictive test for it should utilize a combination of many predictors. Measurement in early pregnancy of a variety of biophysical and biochemical markers implicated in the pathophysiology of PE associated with clinical risk factors has been proposed to predict the development of the syndrome, thereby mitigating an adverse outcome.

EXPERT OPINION

The identification of reliable indicators is a clinically relevant issue that could result in early therapeutic intervention and leading to the prevention of maternal and fetal injuries before the manifestation of clinical signs. Many factors complicate the prevention of PE cases. Most are attributed to unknown etiology, the low predictive value of current screening tests and the several presentations of the disease. Although preventative treatments have been studied extensively, an effective intervention to avoid the development of PE has not yet been discovered.