The value of elevated second-trimester beta-human chorionic gonadotropin in predicting development of preeclampsia

Efficient isolation of encoded microparticles in a degassed micromold for highly sensitive and multiplex immunoassay with signal amplification

Multiplex detection of low-abundance protein biomarkers in biofluids can contribute to diverse biomedical fields such as early diagnosis and precision medicine. However, conventional techniques such as digital ELISA, microarray, and hydrogel-based assay still face limitations in terms of efficient protein detection due to issues with multiplexing capability, sensitivity, or complicated assay procedures. In this study, we present the degassed micromold-based particle isolation technique for highly sensitive and multiplex immunoassay with enzymatic signal amplification. Using degassing treatment of nanoporous polydimethylsiloxane (PDMS) micromold, the encoded particles are isolated in the mold within 5 min absorbing trapped air bubbles into the mold by air suction capability. Through 10 min of signal amplification in the isolated spaces by fluorogenic substrate and horseradish peroxidase labeled in the particle, the assay signal is amplified with one order of magnitude compared to that of the standard hydrogel-based assay. Using the signal amplification assay, vascular endothelial growth factor (VEGF) and chorionic gonadotropin beta (CG beta), the preeclampsia-related protein biomarkers, are quantitatively detected with a limit of detection (LoD) of 249 fg/mL and 476 fg/mL in phosphate buffer saline. The multiplex immunoassay is conducted to validate negligible non-specific detection signals and robust recovery rates in the multiplex assay. Finally, the VEGF and CG beta in real urine samples are simultaneously and quantitatively detected by the developed assay. Given the high sensitivity, multiplexing capability, and process simplicity, the presented particle isolation-based signal amplification assay holds significant potential in biomedical and proteomic fields.

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.

Mechanobiological regulation of placental trophoblast fusion and function through extracellular matrix rigidity

The syncytiotrophoblast is a multinucleated layer that plays a critical role in regulating functions of the human placenta during pregnancy. Maintaining the syncytiotrophoblast layer relies on ongoing fusion of mononuclear cytotrophoblasts throughout pregnancy, and errors in this fusion process are associated with complications such as preeclampsia. While biochemical factors are known to drive fusion, the role of disease-specific extracellular biophysical cues remains undefined. Since substrate mechanics play a crucial role in several diseases, and preeclampsia is associated with placental stiffening, we hypothesize that trophoblast fusion is mechanically regulated by substrate stiffness. We developed stiffness-tunable polyacrylamide substrate formulations that match the linear elasticity of placental tissue in normal and disease conditions, and evaluated trophoblast morphology, fusion, and function on these surfaces. Our results demonstrate that morphology, fusion, and hormone release is mechanically-regulated via myosin-II; optimal on substrates that match healthy placental tissue stiffness; and dysregulated on disease-like and supraphysiologically-stiff substrates. We further demonstrate that stiff regions in heterogeneous substrates provide dominant physical cues that inhibit fusion, suggesting that even focal tissue stiffening limits widespread trophoblast fusion and tissue function. These results confirm that mechanical microenvironmental cues influence fusion in the placenta, provide critical information needed to engineer better in vitro models for placental disease, and may ultimately be used to develop novel mechanically-mediated therapeutic strategies to resolve fusion-related disorders during pregnancy.

Biomimetic Micropatterned Adhesive Surfaces To Mechanobiologically Regulate Placental Trophoblast Fusion

The placental syncytiotrophoblast is a giant multinucleated cell that forms a tree-like structure and regulates transport between mother and baby during development. It is maintained throughout pregnancy by continuous fusion of trophoblast cells, and disruptions in fusion are associated with considerable adverse health effects including diseases such as preeclampsia. Developing predictive control over cell fusion in culture models is hence of critical importance in placental drug discovery and transport studies, but this can currently be only partially achieved with biochemical factors. Here, we investigate whether biophysical signals associated with budding morphogenesis during development of the placental villous tree can synergistically direct and enhance trophoblast fusion. We use micropatterning techniques to manipulate physical stresses in engineered microtissues and demonstrate that biomimetic geometries simulating budding robustly enhance fusion and alter spatial patterns of synthesis of pregnancy-related hormones. These findings indicate that biophysical signals play a previously unrecognized and significant role in regulating placental fusion and function, in synergy with established soluble signals. More broadly, our studies demonstrate that biomimetic strategies focusing on tissue mechanics can be important approaches to design, build, and test placental tissue cultures for future studies of pregnancy-related drug safety, efficacy, and discovery.

Multiplexed immunoassay using post-synthesis functionalized hydrogel microparticles

In response to a growing demand for simultaneous detection of multiple proteins in a single sample, multiplex immunoassay platforms have emerged at the forefront of proteomic analysis. In particular, detections using graphically encoded hydrogel microparticles synthesized via flow lithography have received attention for integrating a hydrogel, a substrate that can provide enhanced kinetics and high loading capacity, into the bead-based multiplex platform. Currently, the method of microparticle functionalization involves copolymerization of antibodies with the gel during particle synthesis. However, its practical operation is too precarious to be adopted because antibodies are susceptible to aggregation due to incompatibility with hydrophobic photoinitiators used in the photo-induced gel polymerization. In this work, we present a multiplex immunoassay platform that uses encoded hydrogel microparticles that are functionalized after particle synthesis by conjugating antibodies with remnant active groups readily available in the hydrogels. The method not only precludes antibody aggregation but also augments the loading density of the antibodies, which translates into enhanced detection performance. In addition to multiplexing, our platform demonstrates high sensitivity, a broad assay range, and a fast detection rate that outperform the enzyme linked immunosorbent assay (ELISA).

The endocrine function of human placenta: an overview

During pregnancy, several tightly coordinated and regulated processes take place to enable proper fetal development and gestational success. The formation and development of the placenta is one of these critical pregnancy events. This organ plays essential roles during gestation, including fetal nourishment, support and protection, gas exchange and production of several hormones and other mediators. Placental hormones are mainly secreted by the syncytiotrophoblast, in a highly and tightly regulated way. These hormones are important for pregnancy establishment and maintenance, exerting autocrine and paracrine effects that regulate decidualization, placental development, angiogenesis, endometrial receptivity, embryo implantation, immunotolerance and fetal development. In addition, because they are released into maternal circulation, the profile of their blood levels throughout pregnancy has been the target of intense research towards finding potential robust and reliable biomarkers to predict and diagnose pregnancy-associated complications. In fact, altered levels of these hormones have been associated with some pathologies, such as chromosomal anomalies or pre-eclampsia. This review proposes to revise and update the main pregnancy-related hormones, addressing their major characteristics, molecular targets, function throughout pregnancy, regulators of their expression and their potential clinical interest.

Preeclampsia: Definitions, screening tools and diagnostic criteria in the supersonic era

Preeclampsia is still a major risk factor for maternal-fetal health. Therefore, early identification of pregnant women at risk for preeclampsia is a big priority in obstetrics in order to decrease the mortality and morbidity associated with this disease. On the basis of well known and new pathophysiological mechanisms of preeclampsia, different biochemical and ultrasonographic parameters have been investigated in the literature, without finding an ideal marker for early screening. In this brief review, we present the best studied ultrasonographic markers and the most recent genetic factors and promising emerging biomarkers of preeclampsia, to date. We hope that in the future the combination of these tests will allow us to predict which women are at risk of preeclampsia.

Second- and third-trimester biochemical and ultrasound markers predictive of ischemic placental disease

Ischemic placental disease is a recently coined term that describes the vascular insufficiency now believed to be an important etiologic factor in preeclampsia, intrauterine fetal growth restriction, and placental abruption. Given the increased risk for poor maternal and fetal outcomes, early prediction and prevention of this disorder is of significant clinical interest for many. In this article, we review the second- and third-trimester serum and ultrasound markers predictive of ischemic placental disease. Limited first-trimester data is also presented. While current studies report a statistical association between marker levels and various adverse perinatal outcomes, the observed diagnostic accuracy is below the threshold required for clinical utility. An exception to this generalization is uterine artery Doppler for the prediction of early-onset preeclampsia. Metabolomics is a relatively new analytic platform that holds promise as a first-trimester marker for the prediction of both early- and late-onset preeclampsia.

Second trimester serum alpha-fetoprotein level is a significant positive predictor for intrauterine growth restriction in pregnant women with hyperemesis gravidarum

OBJECTIVE

The aim of this study was to determine the association between three parameters of second trimester serum secreening and preterm labor and intrauterine growth restriction (IUGR) in patients with hyperemesis gravidarum (HG).

MATERIAL AND METHODS

A prospective study on 429 pregnancies with HG was designed to determine the association between alpha-fetoprotein (AFP), unconjugated estriol (uE3), human chorionic gonadotropin (HCG) and pregnancy prognosis in terms of preterm labor, IUGR and birth weight.

RESULTS

In our study group the mean age of patients was 25.4±3.8 years. Mean birth weight was 3180±555 g. Mean AFP, uE3, hCG levels in the study group were 1.44±0.65 MoM, 0.91±0.38 MoM, 1.09±0.64 MoM, respectively. Twenty nine (6.8%) patients delivered before 37 weeks of gestation and 52 (12.1%) patients developed IUGR. Mean MoM values of AFP among patients with preterm labor, IUGR and normal delivery were 1.35±0.45, 1.97±0.81, 1.34±0.58 MoM, respectively (p<0.001). Mean MoM values of hCG among patients with preterm labor, IUGR and normal delivery were 1.46±0.90, 1.35±0.89, 1±0.5 MoM respectively (p<0.001). Mean MoM values of uE3 among patients with preterm labor, IUGR and normal delivery were 0.75±0.25, 0.80±0.30, 0.95±0.40 MoM, respectively (p=0.003). Odds ratio of AFP>1.55 was 3.73 (95% CI, 1.99-6.98, p<0.001) for IUGR after adjustment for HCG.

CONCLUSION

Our study suggests that AFP levels of the second trimester screening test higher than 1.55 MoM is significantly associated with IUGR in hyperemesis gravidarum. The second trimester screening test can predict poor outcome in HG.

Circulating predictive biomarkers in preeclampsia

The aim of the paper was to review promising prediction biomarkers for preeclampsia. The methods included review of abstracts on PubMed, using "preeclampsia", "biomarker", "prediction" as key words, followed by review of primary papers investigating blood based biomarkers. Angiogenic factors, such as PlGf and sFlt1, and PP13 seem presently to have the best predictive test values for preeclampsia, but sensitivity and specificity is still too low to prove useful in a population screening setting. Biomarker testing should still be part of research protocols. Biomarkers could provide useful in selecting high-risk women for prophylactic trials as well as identifying pregnancies that could profit from closer follow-up.

Can Serum HCG Values Be Used in the Differential Diagnosis of Pregnancy Complicated by Hypertension?

OBJECTIVE

The aim of our study is to determine whether the serum human chorionic gonadotropin (hCG) level is helpful in the differential diagnosis and in the clinical management and follow-up of preeclampsia, superimposed preeclampsia, and chronic hypertension during the third trimester.

MATERIAL AND METHODS

Eighty hypertensive pregnant patients, who had been hospitalized, and 25 normotensive pregnant patients, who attended the outpatient perinatology clinic in Zeynep Kamil Women and Pediatric Diseases Education and Research Hospital between June 2001 and September 2001 were enrolled in the study. These patients were evaluated in five groups: mild preeclamptic, severe preeclamptic, superimposed preeclamptic, chronic hypertensive, and normotensive groups. The geometric means of hCG levels of these groups were compared with each other and cutoff levels for differential diagnosis were determined.

RESULTS

The geometric mean of hCG levels was established as 17,361.31 mIU/mL in the mild preeclamptic group, 49,817.59 mIU/mL in the severe preeclamptic group, 41,101.09 mIU/mL in the superimposed preeclamptic group, 12,558.57 mIU/mL in the chronic hypertensive group, and 9647.98 mIU/mL in the normotensive group. When the geometric mean of the severe preeclamptic group was compared with the results of the normotensive patients, mild preeclamptic patients, chronic hypertensive patients, and superimposed preeclamptic patients, the mean hCG value of severe preeclamptic group was statistically significantly higher than all of the other groups (p < 0.001) except for the latter. The geometric mean of hCG levels of severe preeclamptic patients was compared with the geometric mean of hCG levels of superimposed preeclamptic patients (p > 0.05). The geometric mean of hCG levels in the chronic hypertensive group was lower than that of the superimposed preeclamptic group and the difference was statistically significant (p < 0.001). The geometric mean of hCG levels of the chronic hypertensive group was not significantly different from the results of the mild preeclamptic group and the normotensive group. There was, however, a statistically significant difference between the geometric means of hCG levels of mild preeclamptic patients and normotensive group (p < 0.001). The cutoff value of hCG was determined as 25,000 mIU/mL in differentiation of chronic hypertension from the severe preeclampsia, as 20,000 mIU/mL in differentiation of chronic hypertension from the superimposed preeclampsia, and as 30,000 mIU/mL in differentiation of severe preeclampsia from mild preeclampsia.

CONCLUSION

The maternal serum hCG level is a useful laboratory tool when managing and treating hypertensive disorders that complicate pregnancy. The serum hCG level is especially significant in severe preeclampsia and superimposed preeclampsia. Therefore, a high serum hCG level can be a helpful marker in the diagnosis and clinical management by preventing possible complications resulting from severe and superimposed preeclampsia.

Obstetrical complications associated with abnormal maternal serum markers analytes

OBJECTIVE

To review the obstetrical outcomes associated with abnormally elevated or decreased level of one or more of the most frequently measured maternal serum marker analytes used in screening for aneuploidy. To provide guidance to facilitate the management of pregnancies that have abnormal levels of one of more markers and to assess the usefulness of these markers as a screening test.

OPTIONS

Perinatal outcomes associated with abnormal levels of maternal serum markers analytes are compared with the outcomes of pregnancies with normal levels of the same analytes or the general population.

EVIDENCE

The Cochrane Library and Medline were searched for English-language articles published from 1966 to February 2007, relating to maternal serum markers and perinatal outcomes. Search terms included PAPP-A (pregnancy associated plasma protein A), AFP (alphafetoprotein), hCG (human chorionic gonadotropin), estriol, unconjugated estriol, inhibin, inhibin-A, maternal serum screen, triple marker screen, quadruple screen, integrated prenatal screen, first trimester screen, and combined prenatal screen. All study types were reviewed. Randomized controlled trials were considered evidence of the highest quality, followed by cohort studies. Key individual studies on which the recommendations are based are referenced. Supporting data for each recommendation are summarized with evaluative comments and references. The evidence was evaluated using the guidelines developed by the Canadian Task Force on Preventive Health Care.

VALUES

The evidence collected was reviewed by the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada.

BENEFITS, HARMS, AND COSTS

The benefit expected from this guideline is to facilitate early detection of potential adverse pregnancy outcomes when risks are identified at the time of a maternal serum screen. It will help further stratification of risk and provide options for pregnancy management to minimize the impact of pregnancy complications. The potential harms resulting from such practice are associated with the so called false positive (i.e., uncomplicated pregnancies labelled at increased risk for adverse perinatal outcomes), the potential stress associated with such a label, and the investigations performed for surveillance in this situation. No cost-benefit analysis is available to assess costs and savings associated with this guideline. SUMMARY STATEMENTS: 1. An unexplained level of a maternal serum marker analyte is defined as an abnormal level after confirmation of gestational age by ultrasound and exclusion of maternal, fetal, or placental causes for the abnormal level. (III) 2. Abnormally elevated levels of serum markers are associated with adverse pregnancy outcomes in twin pregnancies, after correction for the number of fetuses. Spontaneous or planned mutifetal reductions may result in abnormal elevations of serum markers. (II-2) RECOMMENDATIONS: 1. In the first trimester, an unexplained low PAPP-A (< 0.4 MoM) and/or a low hCG (< 0.5 MoM) are associated with an increased frequency of adverse obstetrical outcomes, and, at present, no specific protocol for treatment is available. (II-2A) In the second trimester, an unexplained elevation of maternal serum AFP (> 2.5 MoM), hCG (> 3.0 MoM), and/or inhibin-A (> or =2.0 MoM) or a decreased level of maternal serum AFP (< 0.25 MoM) and/or unconjugated estriol (< 0.5 MoM) are associated with an increased frequency of adverse obstetrical outcomes, and, at present, no specific protocol for treatment is available. (II-2A) 2. Pregnant woman with an unexplained elevated PAPP-A or hCG in the first trimester and an unexplained low hCG or inhibin-A and an unexplained elevated unconjugated estriol in the second trimester should receive normal antenatal care, as this pattern of analytes is not associated with adverse perinatal outcomes. (II-2A) 3. The combination of second or third trimester placenta previa and an unexplained elevated maternal serum AFP should increase the index of suspicion for placenta accreta, increta, or percreta. (II-2B) An assessment (ultrasound, MRI) of the placental-uterine interface should be performed. Abnormal invasion should be strongly suspected, and the planning of delivery location and technique should be done accordingly. (III-C) 4. A prenatal consultation with the medical genetics department is recommended for low unconjugated estriol levels (<0.3 MoM), as this analyte pattern can be associated with genetic conditions. (II-2B) 5. The clinical management protocol for identification of potential adverse obstetrical outcomes should be guided by one or more abnormal maternal serum marker analyte value rather than the false positive screening results for the trisomy 21 and/or the trisomy 18 screen. (II-2B) 6. Pregnant woman who are undergoing renal dialysis or who have had a renal transplant should be offered maternal serum screening, but interpretation of the result is difficult as the level of serum hCG is not reliable. (II-2A) 7. Abnormal maternal uterine artery Doppler in association with elevated maternal serum AFP, hCG, or inhibin-A or decreased PAPP-A identifies a group of women at greater risk of IUGR and gestational hypertension with proteinuria. Uterine artery Doppler measurements may be used in the evaluation of an unexplained abnormal level of either of these markers. (II-2B) 8. Further research is recommended to identify the best protocol for pregnancy management and surveillance in women identified at increased risk of adverse pregnancy outcomes based on an abnormality of a maternal serum screening analyte. (III-A) 9. In the absence of evidence supporting any specific surveillance protocol, an obstetrician should be consulted in order to establish a fetal surveillance plan specific to the increased obstetrical risks (maternal and fetal) identified. This plan may include enhanced patient education on signs and symptoms of the most common complications, increased frequency of antenatal visits, increased ultrasound (fetal growth, amniotic fluid levels), and fetal surveillance (biophysical profile, arterial and venous Doppler), and cervical length assessment. (III-A) 10. Limited information suggests that, in women with elevated hCG in the second trimester and/or abnormal uterine artery Doppler (at 22-24 weeks), low-dose aspirin (60-81 mg daily) is associated with higher birthweight and lower incidence of gestational hypertension with proteinuria. This therapy may be used in women who are at risk. (II-2B) 11. Further studies are recommended in order to assess the benefits of low-dose aspirin, low molecular weight heparin, or other therapeutic options in pregnancies determined to be at increased risk on the basis of an abnormal maternal serum screening analyte. (III-A) 12. Multiple maternal serum markers screening should not be used at present as a population-based screening method for adverse pregnancy outcomes (such as preeclampsia, placental abruption, and stillbirth) outside an established research protocol, as sensitivity is low, false positive rates are high, and no management protocol has been shown to clearly improve outcomes. (II-2D) When maternal serum screening is performed for the usual clinical indication (fetal aneuploidy and/or neural tube defect), abnormal analyte results can be utilized for the identification of pregnancies at risk and to direct their clinical management. (II-2B) Further studies are recommended to determine the optimal screening method for poor maternal and/or perinatal outcomes. (III-A).

Serum screening with Down's syndrome markers to predict pre-eclampsia and small for gestational age: systematic review and meta-analysis

Background

Reliable antenatal identification of pre-eclampsia and small for gestational age is crucial to judicious allocation of monitoring resources and use of preventative treatment with the prospect of improving maternal/perinatal outcome. The purpose of this systematic review was to determine the accuracy of five serum analytes used in Down's serum screening for prediction of pre-eclampsia and/or small for gestational age.

Methods

The data sources included Medline, Embase, Cochrane library, Medion (inception to February 2007), hand searching of relevant journals, reference list checking of included articles, contact with experts. Two reviewers independently selected the articles in which the accuracy of an analyte used in Downs's serum screening before the 25^th gestational week was associated with the occurrence of pre-eclampsia and/or small for gestational age without language restrictions. Two authors independently extracted data on study characteristics, quality and results.

Results

Five serum screening markers were evaluated. 44 studies, testing 169,637 pregnant women (4376 pre-eclampsia cases) and 86 studies, testing 382,005 women (20,339 fetal growth restriction cases) met the selection criteria. The results showed low predictive accuracy overall. For pre-eclampsia the best predictor was inhibin A>2.79MoM positive likelihood ratio 19.52 (8.33,45.79) and negative likelihood ratio 0.30 (0.13,0.68) (single study). For small for gestational age it was AFP>2.0MoM to predict birth weight < 10^th centile with birth < 37 weeks positive likelihood ratio 27.96 (8.02,97.48) and negative likelihood ratio 0.78 (0.55,1.11) (single study). A potential clinical application using aspirin as a treatment is given as an example.

There were methodological and reporting limitations in the included studies thus studies were heterogeneous giving pooled results with wide confidence intervals.

Conclusion

Down's serum screening analytes have low predictive accuracy for pre-eclampsia and small for gestational age. They may be a useful means of risk assessment or of use in prediction when combined with other tests.

Inhibins as diagnostic markers in human reproduction

Over the past 75 years, many publications have focused on measurement of inhibin concentration and/or activity in biological samples in order to understand its role in physiology and disease. This chapter highlights the accomplishments within this area of research over the past decade including development of specific inhibin assays. Inhibin A is a marker of dominant follicle and corpus luteum activity and decreases in polycystic ovary syndrome (PCOS). Inhibin A increases in gestational diseases such as pre-eclampsia and fetal Down's syndrome, and this increase in inhibin A improves early diagnosis of both conditions. The measurement of inhibin A in women with threatened abortion provides useful information about the likelihood of pregnancy loss. Inhibin B increases markedly in women with granulosa cell tumor and appears closely related to gametogenesis in men, that is, reflecting Sertoli cell activity. On the contrary, Inhibin B decreases in women with declining ovarian function and correlates with female response to ovulation induction. This review evaluates the biochemical significance ofinhibins including their use in clinical practice.

Development of a nomogram to predict occurrence of preeclampsia

OBJECTIVE

The objective was to create a nomogram for the individual prediction of preeclampsia (PE).

STUDY DESIGN

In a prospective population-based study that included 4777 patients, PE occurred in 2.4%. Age, body mass index, parity, previous preeclampsia (PPE), chronic hypertension, diastolic blood pressure (DBP), and proteinuria at first visit, and second trimester ultrasonography and umbilical artery Doppler resistance index (UARI) data were used to develop and calibrate a nomogram based on a multivariate logistic regression model.

RESULTS

Based on multivariate analysis, nulliparity (P=0.002), PPE (P=0.004), DBP (P<0.0001), biparietal diameter (P=0.011), and UARI (P=0.08) were introduced into a nomogram. Based on these variables, the nomogram had good discrimination (area under the ROC curve=0.73, P<0.01) and calibration (unreliability index=-5.2 x 10(-4)). This nomogram was validated by bootstrapping.

CONCLUSION

Our nomogram predicts the probability of preeclampsia. After validation in an independent population, this tool could be used to plan a preventive trial.

The association of triple-marker test results with adverse pregnancy outcomes in low-risk pregnancies with healthy newborns

OBJECTIVE

This study was designed to investigate the relationship between the second trimester maternal serum markers and adverse pregnancy outcomes in healthy newborns.

MATERIALS AND METHODS

A total of 749 women who delivered in our institution with complete follow up and second-trimester triple marker test data available were included in the study. Women with multiple pregnancies, chronic diseases, diabetes mellitus, obesity, smokers and infants with chromosomal and congenital abnormalities were excluded. Maternal serum alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG) and unconjugated estriol (uE(3)) values were investigated in our cohort who developed preeclampsia (n = 28), gestational diabetes (GM) (n = 69), preterm labor-birth (n = 100), oligohydramnios (n = 37) and macrosomia (n = 59) by using receiver operating characteristic (ROC) curve analysis, with chi-square and Pearson's correlation tests.

RESULTS

Women with uE(3) < or = 1.26 MoM (P = 0.001, AUC = 0.666), HCG > 1.04 MoM (P = 0.032, AUC = 0.599) or AFP < or = 0.69 MoM (P = 0.049, AUC = 0.600) values significantly developed oligohydramnios. Also, macrosomic infants were observed in women who had HCG values > 0.86 MoM (P = 0.047, AUC = 0.578). Patients with HCG > 1.04 MoM (P = 0.04, AUC = 0.565) and uE(3) < or =0.88 MoM (P = 0.049, AUC = 0.571) developed GDM. HCG levels > or =2.5 or > or =3 MoM were significantly associated with the development of oligohydramnios [P = 0.005; OR = 4 (95% CI: 1.7-9.7)], [P = 0.008; OR = 4.9 (95% CI: 1.7-13.7)], respectively. When women with adverse (n = 237) and normal (n = 512) outcomes were compared there were significant differences in maternal serum AFP (1.40 +/- 0.84 vs. 1.23 +/- 0.75 MoM, P = 0.006) and uE(3) values (1.38 +/- 1.42 vs. 1.45 +/- 0.98 MoM, P = 0.001).

CONCLUSIONS

Serum estriol, AFP or HCG values in triple test results may be associated with development of oligohydramnios, gestational diabetes and macrosomia in women with healthy and normal appearing fetuses.

The gonadotropins: tissue-specific angiogenic factors?

The gonadotropins, whose members are human chorionic gonadotropin (hCG), lutenizing hormone (LH) and follicle-stimulating hormone (FSH) are a well characterized hormone family known to regulate reproductive functions in both females and males. Recent studies indicate that they can modulate the vascular system of reproductive organs. It was shown that gonadotropins not only influence the expression of vascular endothelial growth factor (VEGF) and both its receptors VEGFR-1 and -2, but also modulate other ubiquitously expressed angiogenic factors like the angiopoietins and their receptor Tie-2, basic fibroblast growth factor or placental-derived growth factor. Some recent data indicates a possible direct action of gonadotropins on endothelial cells. Thus, the gonadotropins act as tissue-specific angiogenic factors providing an optimal vascular supply during the menstrual cycle and early pregnancy in the female reproductive tract as well as in testis. In pathological conditions (e.g. preeclampsia, intrauterine growth restriction, ovarian hyperstimulation or endometriosis), these tightly regulated interactions between the gonadotropins and the ubiquitous angiogenic factors appear to be disturbed. The intent of this short manuscript is to review the current knowledge of the regulatory role of the gonadotropins in vasculo- and angiogenesis. We also review angiogenic actions of thyroid-stimulating hormone (TSH), a glycoprotein closely related to gonadotropins, which display strong gonodal actions.

Unexplained elevated maternal serum β-HCG concentration and adverse pregnancy outcome

OBJECTIVE

To investigate the association between unexplained elevated maternal serum beta-Human chorionic gonadotrophin (HCG) in the second trimester of pregnancy and adverse pregnancy outcome.

METHODS

In a case-controlled study of 3463 women who opted for second-trimester serum screening for Down syndrome, 142 were found to have a serum beta-HCG of > or =3.5 multiples of the median (MoM), 56 of whom had a serum beta-HCG of > or =5.0 MoM. These women were compared with a control group of women with serum beta-HCG within the 95% confidence interval around the median.

RESULTS

In the elevated beta-HCG group (> or =5 MoM) significantly more babies required admission to the special care baby unit (p = 0.02) and were small for gestational age (SGA) (p = 0.03). The mean birth weight was also significantly lower in the group with elevated beta-HCG. Women with a serum beta-HCG of > or =5, > or =6, > or =7 or > or =8 MoM were associated with SGA babies in 40, 44, 64 and 86% respectively. All babies born to the six women with beta-HCG of 8.75-24.1 MoM were SGA.

CONCLUSION

Increased surveillance is necessary in pregnancies where the maternal serum beta-HCG in the second trimester is inexplicably elevated to > or =5 MoM.

The clinical value of combining maternal serum screening and uterine artery Doppler in prediction of adverse pregnancy outcome

Uterine artery Doppler waveform analysis is not offered in routine antenatal care in the UK. The aim of this study is to evaluate a policy of offering uterine artery Doppler ultrasound, in the setting of a District General Hospital, to women who are judged to be at high risk of adverse pregnancy outcome, based on their mid-trimester biochemical serum screening. Data from 73 cases with abnormal serum screening were collected and analysed. Abnormal outcome occurred in 11 cases (16%) including two perinatal deaths. The positive predictive value of adverse outcome was 13% for abnormal serum screening, 26% for human chorionic gonadotropin (hCG) >3 multiples of the median (MOM) and 8% for alfa-fetoprotein (AFP) >2.5 MOM. A total of 56 cases of the study group had uterine artery Doppler at 22 weeks' gestation. Evaluation of the performance of uterine artery Doppler in prediction of adverse pregnancy outcome revealed a sensitivity of 43%, specificity of 70%, a positive predictive value (PPV) of 18% and a negative predictive value (NPV) of 89%. When the presence of diastolic notch was taken to define a positive result the sensitivity remained unchanged, however the specificity, PPV and NPV improved to 91%, 43% and 91%, respectively. In conclusion, the combination of serum markers and abnormal uterine artery Doppler ultrasound improves the identification of women at risk of subsequent pregnancy complications. Raised serum hCG has a better predictive value for adverse pregnancy outcome as opposed to raised serum AFP. In the absence of diastolic notch, the accuracy of abnormal uterine artery Doppler ultrasound is markedly reduced.

Human chorionic gonadotropin levels between 16 and 21 weeks of pregnancy and prediction of pre-eclampsia

OBJECTIVE

To determine whether levels of beta human choriogonadotropin (beta-hCG) during the second trimester are a predictor of pre-eclampsia.

METHODS

A prospective study of 784 women was conducted between their 16th and 20th week of pregnancy. Primigravidas and multigravidas were analyzed separately, and the cutoff point was determined using a receiver operating characteristic curve. The accuracy of beta-hCG levels in the prediction of pre-eclampsia was evaluated. The likelihood ratios were calculated for different levels of beta-hCG in both groups.

RESULTS

Pre-eclampsia prevalence was 7.1% among primigravidas and 4.6% among multigravidas. The cutoff concentration was 2.0 MoM in both groups. For primigravidas and multigravidas, respectively, the area below the curve was 0.96 and 0.95; sensitivity was 88.5% and 100%; specificity was 92.0% and 85.6%; positive predictive value was 0.46 and 0.25; and negative predictive value was 0.99 and 1.0. With a cutoff concentration of 2.0 MoM of beta-hCG, the positive likelihood ratio was 11.1 in primigravidas and 6.9 in multigravidas.

CONCLUSION

This study shows that measuring levels of beta-hCG during the second trimester of pregnancy is useful in clinical practice to identify pregnant women who will develop pre-eclampsia.

Screening for pre-eclampsia by using maternal serum inhibin A, activin A, human chorionic gonadotropin, unconjugated estriol, and alpha-fetoprotein levels and uterine artery Doppler in the second trimester of pregnancy

AIMS

To analyse the predictive power of maternal serum inhibin A, activin A, human chorionic gonadotropin (hCG), unconjugated estriol (uE(3)), alpha-fetoprotein (AFP) levels and uterine artery Doppler in the second trimester of pregnancy in screening for pre-eclampsia.

METHODS

Maternal serum inhibin A, activin A, hCG, uE(3), and AFP levels and uterine artery Doppler were determined in 178 healthy, pregnant women in the second trimester of pregnancy. Serum samples were collected between the 16th and 18th weeks of gestation, and Doppler investigation was performed between the 24th and 26th weeks of gestation. Receiver operating characteristic curves were created to analyse the predictive powers of the above parameters in screening for pre-eclampsia. Different combinations also were analysed.

RESULTS

The rate of pre-eclampsia was 7.9% (14/178). Maternal serum inhibin A, activin A, hCG, AFP levels, the rate of presence of the prediastolic notch and uterine artery resistance index (RI) values in pre-eclamptic pregnancies were significantly higher than those in healthy pregnancies. Presence of the prediastolic notch, uterine artery RI, maternal serum activin A and inhibin A levels had high predictive efficacy, and each had a sensitivity between 70 and 93% and a specificity between 87% and 98%. The addition of inhibin A or activin A measurement to the Doppler velocimetry improved the specificity to 99-100%.

CONCLUSIONS

Maternal serum inhibin A and activin A levels and uterine artery Doppler appear to be useful screening tests during the second trimester for pre-eclampsia. However, addition of these hormonal markers to Doppler velocimetry only slightly improves the predictive efficacy, which appears clinically insignificant.

Prediction of Preeclampsia or Intrauterine Growth Restriction by Second Trimester Serum Screening and Uterine Doppler Velocimetry

OBJECTIVE

To assess the performance of screening for preeclampsia and intrauterine growth restriction by combining second trimester maternal serum screening and uterine Doppler ultrasound.

METHODS

A cohort of 2,615 women underwent both maternal serum screening (using human chorionic gonadotropin (hCG) and alpha-fetoprotein (AFP)), and second trimester uterine artery Doppler. The sensitivity, specificity and predictive value of different combinations of both tests were compared.

RESULTS

The mean values for hCG and AFP were significantly higher in women with subsequent preeclampsia (p < 0.0003 and p < 0.03, respectively). Taking into account obstetrical history, hCG and AFP levels, notching on uterine artery Doppler and parity, the adjusted odds ratios were significantly higher for a high level of hCG for preeclampsia, intrauterine growth restriction (IUGR) and pregnancy-induced hypertension. AFP level >1.5 MoM (multiples of the median) was significantly correlated with subsequent IUGR. The presence of a uterine notch was associated with a significantly higher risk of both preeclampsia and IUGR. The combination of an elevated serum level and the presence of a uterine notch had a positive predictive value (PPV) for preeclampsia of 25 and 21% for hCG and AFP, respectively. The combination of a bilateral notch with a low level of hCG or a high level of AFP had a PPV for IUGR of 50 and 43%, respectively. The sensitivity of the different tests ranged from 2 to 40%.

CONCLUSION

The combination of serum markers and abnormal uterine Doppler ultrasound improves the identification of women at risk for subsequent pregnancy complications. These results should encourage care providers to perform a uterine Doppler ultrasound when serum markers are abnormal. However, the sensitivity of these tests is too low to provide an efficient generalized screening.

World Health Organization Systematic Review of Screening Tests for Preeclampsia

OBJECTIVE

We sought to assess the usefulness of clinical, biophysical, and biochemical tests in the prediction of preeclampsia.

DATA SOURCES

The sources of data we used to conduct this review included the computerized databases MEDLINE (1966 to February 2003), EMBASE, Popline, CINAHL, and LILACS plus reference lists, conference proceedings, textbooks, and contact with experts.

METHODS OF STUDY SELECTION

All cohort or cross-sectional studies reporting data on the relationship between a predictive test that was performed during pregnancy and the development of preeclampsia were eligible for inclusion, whereas case-control studies were excluded. Eighty-seven (211,369 women) of 7,191 potentially relevant articles met inclusion criteria. We evaluated the methodologic quality for each included study.

TABULATION, INTEGRATION, AND RESULTS

Using a standardized protocol, one reviewer selected and extracted data on study characteristics, quality, and accuracy. Data abstracted from each study were arranged in 2 x 2 tables to construct receiver operating characteristics plots (sensitivity against 1 - specificity) and pooled to produce summary likelihood ratios for positive and negative tests results. Moderate predictive accuracy of anticardiolipin antibodies, the presence of bilateral diastolic notches during Doppler ultrasonography, and urinary kallikrein were found in women at low risk of developing preeclampsia. Nevertheless, because the pretest probability of preeclampsia with a positive result was but minimally increased, the clinical use of these tests is limited. Other ultrasonography characteristics and the measurement of fetal and placental peptides showed low predictive accuracy. In populations that were deemed at high risk for preeclampsia, the use of Doppler ultrasonography had low predictive accuracy. No definitive conclusions were possible in the case of many other tests, because the number of studies that met the minimal inclusion criteria was limited.

CONCLUSION

As of 2004, there is no clinically useful screening test to predict the development of preeclampsia. Further prospective, longitudinal studies are needed.

Prenatal screening, epidemiology, diagnosis, and management of preeclampsia

The cause of preeclampsia remains unknown. The disease manifests itself across a broad clinical spectrum from mild to severe, conferring vastly different morbidities and suggesting possibly different disease processes. Oxidative stress, endothelial dysfunction, maternal-fetal immune incompatibility, and abnormal placental implantation are among the suggested causes. The need for a marker or set of markers that allow for definitive diagnosis and assessment of future risk of preeclampsia is tremendous. Ultrasound techniques and several markers have been identified that are increased among patients with preeclampsia, but no test is highly sensitive. In the future, a combination of markers likely will be used to assess risk and, establish the diagnosis, and test treatment strategies. Such an approach would allow for more refined treatment studies of patients who are at highest risk for preeclampsia.

The endocrinology of pre-eclampsia

Pre-eclampsia is a pregnancy specific syndrome that is a principal cause of maternal morbidity and mortality, accounting for almost 15% of pregnancy associated deaths, and is one of the major causes of iatrogenic prematurity among new born babies. The mild form of pre-eclampsia most commonly presents with the features of maternal hypertension and proteinuria, but can swiftly and unpredictably become severe with numerous multisystem complications involving the maternal liver, kidneys, lungs, blood and platelet coagulation and nervous systems. The diverse symptoms of pre-eclampsia have made it a difficult disease not only to define, but also to identify a causative agent for the symptoms. This review examines the complex endocrinological mechanisms believed to be responsible for the extensive complications of pre-eclampsia from the role of placental and endothelial dysfunction, to the causes of the oxidative stress and the ensuing general inflammation. It also highlights current endocrine findings that exhibit the potential for clinical application, as either potential markers or novel therapeutic targets, with the aim of either preventing or altering the course of this life-threatening disease of pregnancy.

Preeclampsia. Part 2: experimental and genetic considerations

Preeclampsia-eclampsia is still one of the leading causes of maternal and fetal morbidity and mortality. Despite active research for many years, the etiology of this disorder exclusive to human pregnancy is an enigma. Recent evidence suggests there may be several underlying causes or predispositions leading to the signs of hypertension, proteinuria, and edema, findings that allow us to make the diagnosis of the "syndrome" of preeclampsia. Despite improved prenatal care, severe preeclampsia and eclampsia still occur. Although understanding of the pathophysiology of these disorders has improved, treatment has not changed significantly in over 50 years. Although postponement of delivery in selected women with severe preeclampsia improves fetal outcome to a degree, this is not done without risk to the mother. In the United States, magnesium sulfate and hydralazine are the most commonly used medications for seizure prophylaxis and hypertension in the intrapartum period. The search for the underlying cause of this disorder and for a clinical marker to predict those women who will develop preeclampsia-eclampsia is ongoing, with its prevention the ultimate goal. This review began with the clinical and pathophysiologic aspects of preeclampsia-eclampsia (Part 1). Now, in Part 2, the experimental observations, the search for predictive factors, and the genetics of this disorder are reviewed.

The role of hyperglycosylated hCG in trophoblast invasion and the prediction of subsequent pre-eclampsia

OBJECTIVE

Hyperglycosylated hCG (HhCG) is the predominant form of chorionic gonadotrophin in states characterized by aggressive trophoblast invasion such as early pregnancy or choriocarcinoma. Pre-eclampsia may be the result of failed or inadequate trophoblast invasion. We investigated whether low levels of maternal urine HhCG levels would predict subsequent pre-eclampsia.

STUDY DESIGN

Mid-trimester urine (14-21 weeks) was collected and frozen from non-hypertensive women undergoing genetic amniocentesis. Inclusion criteria were: normal singleton pregnancies without a prior history of pre-eclampsia, hypertension, diabetes or other vascular disorders. The specimens were subsequently thawed, and HhCG levels standardized to urine creatinine were measured. Maternal charts were reviewed after delivery to determine the development of pre-eclampsia. There were a total of 568 study subjects.

RESULTS

Pre-eclampsia developed in 26 (4.6%) women. There was a significant correlation between low urine HhCG and subsequent pre-eclampsia (Mantel-Haenszel test of linear association: Chi-square 10.52, p=0.001). The mean HhCG level (ng/mg creatinine) was significantly greater in normals than in those destined to develop pre-eclampsia: 42.7 versus 20.3, p=0.002 (Mann-Whitney U-test). There was a progressive increase in the risk of subsequent pre-eclampsia as HhCG levels fell: HhCG < or =0.9 MoM RR (95% CI)=1.51 (1.15-1.98) compared with < or =0.1 MoM 10.42 (2.0-54.3).

CONCLUSION

Low maternal mid-trimester urine HhCG predicted subsequent pre-eclampsia. This appears to support the view that pre-eclampsia results at least in part from poor trophoblast invasion. Thus, HhCG may play a role in trophoblast invasion and measurement of this in urine identifies women at high risk for developing pre-eclampsia.

Predictive value of hormone measurements in maternal and fetal complications of pregnancy

Intrauterine tissues (placenta, amnion, chorion, decidua) express hormones and cytokines that play a decisive role in maternal-fetal physiological interactions. The excessive or deficient release of some placental hormones in association with gestational diseases may reflect an abnormal differentiation of the placenta, an impaired fetal metabolism, or an adaptive response of the feto-placental unit to adverse conditions. This review is focused on the applicability of hormone measurements in the risk assessment, early diagnosis, and management of pregnancies complicated by Down's syndrome, fetal growth restriction, preeclampsia, preterm delivery, and diabetes mellitus. Combined hormonal tests or the combination of hormones and ultrasound may achieve reasonable sensitivity, but research continues to simplify the screening programs without sacrificing their accuracy. Only in a few instances is there sufficient evidence to firmly recommend the routine use of hormone tests to predict maternal and fetal complications, but the judicious use of selected tests may enhance the sensitivity of the risk assessment based solely on clinical and ultrasound examination.

False positive serum biochemical screening and subsequent fetal loss in women less than 35 years of age

OBJECTIVE

To examine the fetal loss rate in women younger than 35 years of age following a false positive serum biochemical screening.

DESIGN

Retrospective analysis of case records between 1991 and 1998.

SETTING

Fetal medicine unit of a large teaching hospital.

POPULATION

Four hundred and fifty-six women with singleton pregnancies and false positive serum biochemical screening for Down's Syndrome (study group). Nine hundred and twelve matched controls with true negative serum biochemical screening (control group).

METHODS

Women of both groups had a second trimester serum screening for Down's Syndrome using alpha fetoprotein, human chorionic gonadotrophin (hCG) and unconjugated oestriol (uE3); and they also underwent genetic amniocentesis.

RESULTS

The overall fetal loss rate in the study group was 5.3% (24/456), compared with 1.65% (15/912) in the control group RR 3.2, 95% CI 1.7-5.99; P < 0.001). The majority of fetal losses in the study group occurred after 28 weeks, while in the controls this happened between 24 and 28 weeks of gestation.

CONCLUSIONS

A false positive serum biochemical screening in women under 35 years of age is associated with a threefold increased risk of subsequent fetal loss. However, most of fetal losses in this group occurred after 28 weeks, indicating that intensive antepartum fetal surveillance could improve the perinatal outcome.

Mid-trimester beta-hCG levels incorporated in a multifactorial model for the prediction of severe pre-eclampsia

Pre-eclampsia remains a major cause of perinatal morbidity and mortality worldwide. Proposed predicting tests for early detection of pregnant women destined to develop pre-eclampsia remain unsatisfactory. The aim of this study was to investigate the clinical utility of combining mid-trimester maternal serum beta-human chorionic gonadotrophin (MShCG) levels with selected clinical determining factors as a multifactorial predictive test for pre-eclampsia. Thirty-nine cases with mild pre-eclampsia and 56 with severe pre-eclampsia were recruited as the study groups. Normotensive women (957) were enrolled as controls. Potential determining risk factors for severe pre-eclampsia were selected using a multiple logistic regression to build various combined prediction models. A receiver-operator characteristic curve was employed to assess the performance of each prediction test for pre-eclampsia. The prediction efficacy of each test was examined by the area under the curve (AUC). Our data show that mid-trimester MShCG levels significantly correlated with severity of pre-eclampsia (Spearman rank correlation coefficient=0.195, p<0.001). Women with mild pre-eclampsia had a 2.61-times greater chance, while women with severe pre-eclampsia had a 6.13-times greater chance of having MShCG exceeding 2.0 multiples of the median than did women with a normal pregnancy. A combined prediction model composed of MShCG levels, body mass index (BMI), parity, and age as a predictive test for severe pre-eclampsia was superior to MShCG levels alone (AUC 0.765 versus 0.648). The integrated multifactorial model could identify women at risk early on for developing severe pre-eclampsia, with a sensitivity of 70% and a specificity of 71%. Thus, we demonstrate a potentially effective and convenient method by which women at risk for developing severe pre-eclampsia can be identified early, based on a multifactorial predictive model composed of midtrimester MShCG levels, BMI, parity, and age.

Serum inhibin A and activin A are elevated prior to the onset of pre-eclampsia

Serum inhibin A and activin A concentrations increase in pre-eclampsia. We investigated the time courses of the changes in relation to the onset of the maternal syndrome and if their measurement could be useful for clinical prediction particularly in relation to early onset disease, the most severe of the clinical presentations. Serial samples were taken from 1496 healthy nulliparae. Changes in activin A and inhibin A were analysed in women with: early onset pre-eclampsia (n = 11), pre-eclampsia delivering at 34-36 weeks (n = 14), term pre-eclampsia (n = 25) and gestational hypertension (n = 25); and in a subset with uncomplicated pregnancies (n = 25). Serum inhibin A and activin A were increased in all groups prior to pre-eclampsia, before 20 weeks in those with early onset pre-eclampsia. Screening efficacy was determined at 15-19 and 21-25 weeks in all women who developed pre-eclampsia (n = 70) and randomly selected controls (n = 240). Predictive sensitivities were low (16-59%) but much better for early onset pre-eclampsia: 67 and 44% at 15-19 weeks and 89 and 89% at 21-25 weeks for inhibin A and activin A respectively. Hence, serum inhibin A and activin A concentrations increase before the onset of pre-eclampsia at gestational ages that depend on when pre-eclampsia develops. On their own such measures are unlikely to prove efficient for screening.

Can antenatal clinical and biochemical markers predict the development of severe preeclampsia?

OBJECTIVE

This study was undertaken to develop a multivariable clinical predictive rule for severe preeclampsia using second-trimester clinical factors and biochemical markers.

STUDY DESIGN

We performed a retrospective cohort study of all pregnant patients with single gestations from 1995 through 1997 for whom we had complete follow-up data. Through medical record review we determined whether patients had severe preeclampsia develop according to American College of Obstetricians and Gynecologists criteria. Case patients with severe preeclampsia were compared with control subjects with respect to clinical data and multiple-marker screening test results. With potential predictive factors identified in the bivariate and stratified analyses both an explanatory logistic regression model and a clinical prediction rule were created. Patients were assigned a predictive score according to the presence or absence of predictive factors, and receiver operating characteristic analysis was used to determine the optimal score cutoff point for prediction of severe preeclampsia with maximal sensitivity.

RESULTS

Among the 1998 patients we found 49 patients with severe preeclampsia (prevalence, 2.5%). After we controlled for confounding variables, case patients and control subjects had similar human chorionic gonadotropin and alpha-fetoprotein levels, and the only variables that remained significantly associated with severe preeclampsia were nulliparity (relative risk, 3.8; 95% confidence interval, 1.7-8.3), history of preeclampsia (relative risk, 5.0; 95% confidence interval, 1.7-17.2), elevated screening mean arterial pressure (relative risk, 3.5; 95% confidence interval, 1.7-7.2), and low unconjugated estriol concentration (relative risk, 1.7; 95% confidence interval, 0.9-3.4). Our predictive model for severe preeclampsia, which included only these 4 variables, had a sensitivity of 76% and a specificity of 46%.

CONCLUSION

Even after incorporation of the strongest risk factors, our predictive model had only modest sensitivity and specificity for discrimination of patients at risk for development of severe preeclampsia. The addition of the human chorionic gonadotropin and alpha-fetoprotein biochemical markers did not enhance the model's predictive value for severe preeclampsia.

Second-trimester serum chorionic gonadotropin concentrations and complications and outcome of pregnancy

BACKGROUND

Maternal serum chorionic gonadotropin is measured to screen for fetal chromosomal abnormalities. Whether the results can also be used to predict the risk of complications or an adverse outcome of pregnancy is not known.

METHODS

We reviewed the medical records of 28,743 girls and women in whom chorionic gonadotropin was measured during the second trimester of pregnancy (between July 1, 1995, and January 31, 1997), seeking information about the complications and outcome of their pregnancies. We excluded girls and women who had preexisting risk factors for complications or an adverse outcome of pregnancy.

RESULTS

Higher serum chorionic gonadotropin concentrations were associated with higher rates of stillbirth (odds ratio for every increase in chorionic gonadotropin of 1 multiple of the median, 1.4; 95 percent confidence interval, 1.1 to 1.9). There was no relation between higher serum chorionic gonadotropin concentrations and the risk of gestational diabetes, premature rupture of membranes or intrauterine growth retardation or small size for gestational age (odds ratio, 1.1; 95 percent confidence interval, 0.9 to 1.2). Higher serum chorionic gonadotropin concentrations were associated with a risk of placental abnormalities (odds ratio, 1.5; 95 percent confidence interval, 1.3 to 1.7), pregnancy-induced hypertension (odds ratio, 1.4; 95 percent confidence interval, 1.3 to 1.5), and preterm delivery without pregnancy-induced hypertension (odds ratio, 1.1; 95 percent confidence interval, 1.0 to 1.2). Inclusion in certain racial or ethnic categories (black, Filipino or Pacific Islander, unknown race or ethnic group, and "other," which included those of Middle Eastern descent and Native Americans) was a better predictor of the risk of an adverse outcome than serum chorionic gonadotropin values.

CONCLUSIONS

Measurements of serum chorionic gonadotropin are of little clinical value for predicting the risk of complications and the outcome of pregnancy.

Prediction of preeclampsia

The onset of preeclampsia at or near to term is associated with low maternal and neonatal morbidity and mortality. In contrast, those patients (1%) who suffer early onset preeclampsia engender significant maternal and perinatal morbidity and mortality. Therefore, because of the lack of proven prophylaxis for preeclampsia, prediction of risk or identification of subclinical disease is desirable to identify patients for more intensive observation. There are certain at-risk groups of patients such as those with chronic hypertension, pregestational diabetes, multifetal gestation, and previous preeclampsia. These patients account for the majority of cases of preeclampsia in multiparas, yet only account for 14% of preeclampsia in nulliparous women. Thus, the majority of cases of preeclampsia arises from nulliparous women without medical complications at low risk. Differences in the time of onset, severity, and organ system involvement suggest there may be different underlying etiologies that ultimately lead to preeclampsia manifested as the triad of maternal hypertension, proteinuria, and edema. Distinct markers therefore may identify subgroups of at-risk patients with separate underlying causes. These markers ultimately could be used for diagnosis of disease before the clinical appearance of maternal disease (hypertension, proteinuria, and edema). Based on data from patients with established disease, with the involvement of various organ systems, potential candidate markers would include renal function (kallikrein-creatinine); coagulation and fibrinolytic systems and platelet activation (platelet volume); markers of vascular function (fibronectin, prostacyclin, thromboxane) and oxidant stress (lipid peroxides, 8-isoprostane, antioxidants, anticardiolipin antibodies, hemoglobin, iron, transferrin, homocysteine, hypertriglyceridemia, albumin isoforms); placental peptide hormones (CRH, CRHbp, activin, inhibin, hCG); vascular resistance (uteroplacental flow velocity waveforms); genetic markers; insulin resistance; and glucose intolerance. Although cross-sectional studies have identified these potential markers, they need to be evaluated in prospective longitudinal studies with rigorous definition of outcome to determine if they are useful in predicting preeclampsia and whether they can identify different subgroups of patients.