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

Development and validation of prediction models for fetal growth restriction and birthweight: an individual participant data meta-analysis

Background

Fetal growth restriction is associated with perinatal morbidity and mortality. Early identification of women having at-risk fetuses can reduce perinatal adverse outcomes.

Objectives

To assess the predictive performance of existing models predicting fetal growth restriction and birthweight, and if needed, to develop and validate new multivariable models using individual participant data.

Design

Individual participant data meta-analyses of cohorts in International Prediction of Pregnancy Complications network, decision curve analysis and health economics analysis.

Participants

Pregnant women at booking. External validation of existing models (9 cohorts, 441,415 pregnancies); International Prediction of Pregnancy Complications model development and validation (4 cohorts, 237,228 pregnancies).

Predictors

Maternal clinical characteristics, biochemical and ultrasound markers.

Primary outcomes

fetal growth restriction defined as birthweight <10th centile adjusted for gestational age and with stillbirth, neonatal death or delivery before 32 weeks' gestation birthweight.

Analysis

First, we externally validated existing models using individual participant data meta-analysis. If needed, we developed and validated new International Prediction of Pregnancy Complications models using random-intercept regression models with backward elimination for variable selection and undertook internal-external cross-validation. We estimated the study-specific performance (c-statistic, calibration slope, calibration-in-the-large) for each model and pooled using random-effects meta-analysis. Heterogeneity was quantified using τ2 and 95% prediction intervals. We assessed the clinical utility of the fetal growth restriction model using decision curve analysis, and health economics analysis based on National Institute for Health and Care Excellence 2008 model.

Results

Of the 119 published models, one birthweight model (Poon) could be validated. None reported fetal growth restriction using our definition. Across all cohorts, the Poon model had good summary calibration slope of 0.93 (95% confidence interval 0.90 to 0.96) with slight overfitting, and underpredicted birthweight by 90.4 g on average (95% confidence interval 37.9 g to 142.9 g). The newly developed International Prediction of Pregnancy Complications-fetal growth restriction model included maternal age, height, parity, smoking status, ethnicity, and any history of hypertension, pre-eclampsia, previous stillbirth or small for gestational age baby and gestational age at delivery. This allowed predictions conditional on a range of assumed gestational ages at delivery. The pooled apparent c-statistic and calibration were 0.96 (95% confidence interval 0.51 to 1.0), and 0.95 (95% confidence interval 0.67 to 1.23), respectively. The model showed positive net benefit for predicted probability thresholds between 1% and 90%. In addition to the predictors in the International Prediction of Pregnancy Complications-fetal growth restriction model, the International Prediction of Pregnancy Complications-birthweight model included maternal weight, history of diabetes and mode of conception. Average calibration slope across cohorts in the internal-external cross-validation was 1.00 (95% confidence interval 0.78 to 1.23) with no evidence of overfitting. Birthweight was underestimated by 9.7 g on average (95% confidence interval -154.3 g to 173.8 g).

Limitations

We could not externally validate most of the published models due to variations in the definitions of outcomes. Internal-external cross-validation of our International Prediction of Pregnancy Complications-fetal growth restriction model was limited by the paucity of events in the included cohorts. The economic evaluation using the published National Institute for Health and Care Excellence 2008 model may not reflect current practice, and full economic evaluation was not possible due to paucity of data.

Future work

International Prediction of Pregnancy Complications models' performance needs to be assessed in routine practice, and their impact on decision-making and clinical outcomes needs evaluation.

Conclusion

The International Prediction of Pregnancy Complications-fetal growth restriction and International Prediction of Pregnancy Complications-birthweight models accurately predict fetal growth restriction and birthweight for various assumed gestational ages at delivery. These can be used to stratify the risk status at booking, plan monitoring and management.

Study registration

This study is registered as PROSPERO CRD42019135045.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/148/07) and is published in full in Health Technology Assessment; Vol. 28, No. 14. See the NIHR Funding and Awards website for further award information.

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.

Circulating biomarkers associated with placental dysfunction and their utility for predicting fetal growth restriction

Fetal growth restriction (FGR) leading to low birth weight (LBW) is a major cause of neonatal morbidity and mortality worldwide. Normal placental development involves a series of highly regulated processes involving a multitude of hormones, transcription factors, and cell lineages. Failure to achieve this leads to placental dysfunction and related placental diseases such as pre-clampsia and FGR. Early recognition of at-risk pregnancies is important because careful maternal and fetal surveillance can potentially prevent adverse maternal and perinatal outcomes by judicious pregnancy surveillance and careful timing of birth. Given the association between a variety of circulating maternal biomarkers, adverse pregnancy, and perinatal outcomes, screening tests based on these biomarkers, incorporating maternal characteristics, fetal biophysical or circulatory variables have been developed. However, their clinical utility has yet to be proven. Of the current biomarkers, placental growth factor and soluble fms-like tyrosine kinase 1 appear to have the most promise for placental dysfunction and predictive utility for FGR.

Combined maternal risk factors and the Quadruple test to predict late-onset preeclampsia in pregnant Thai women

BACKGROUND

This study aimed to evaluate the predictive power of a model combining maternal risk factors and the Quadruple screen test for late-onset preeclampsia (PE).

METHODS

All pregnant women that received the Quadruple test for Down syndrome at 15^+ 0-20^+ 6 weeks' gestation were recruited. Maternal serum α-fetoprotein, β-human chorionic gonadotropin, unconjugated estriol, and inhibin A were measured as multiples of the median. A logistic regression model was used to identify predictors associated with late-onset PE with severe features. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to assess the model's predictive ability.

RESULTS

Fifty-five of the 2,000 pregnant women had PE, and 31 of 55 women had late-onset PE. Multivariate analysis identified maternal age ≥ 35 years, inhibin A, history of previous PE, history of infertile, cardiac disease, chronic hypertension, and thyroid disease as significant risk factors. The area under the curve of the receiver operating characteristic curve was 0.78. The likelihood ratio to predict late-onset PE was 49.4 (total score > 60).

CONCLUSIONS

Our model combining serum inhibin A with maternal risk factors was useful in predicting late-onset PE. Close monitoring of these patients is recommended.

Validation and development of models using clinical, biochemical and ultrasound markers for predicting pre-eclampsia: an individual participant data meta-analysis

BACKGROUND

Pre-eclampsia is a leading cause of maternal and perinatal mortality and morbidity. Early identification of women at risk is needed to plan management.

OBJECTIVES

To assess the performance of existing pre-eclampsia prediction models and to develop and validate models for pre-eclampsia using individual participant data meta-analysis. We also estimated the prognostic value of individual markers.

DESIGN

This was an individual participant data meta-analysis of cohort studies.

SETTING

Source data from secondary and tertiary care.

PREDICTORS

We identified predictors from systematic reviews, and prioritised for importance in an international survey.

PRIMARY OUTCOMES

Early-onset (delivery at < 34 weeks' gestation), late-onset (delivery at ≥ 34 weeks' gestation) and any-onset pre-eclampsia.

ANALYSIS

We externally validated existing prediction models in UK cohorts and reported their performance in terms of discrimination and calibration. We developed and validated 12 new models based on clinical characteristics, clinical characteristics and biochemical markers, and clinical characteristics and ultrasound markers in the first and second trimesters. We summarised the data set-specific performance of each model using a random-effects meta-analysis. Discrimination was considered promising for C-statistics of ≥ 0.7, and calibration was considered good if the slope was near 1 and calibration-in-the-large was near 0. Heterogeneity was quantified using I ² and τ². A decision curve analysis was undertaken to determine the clinical utility (net benefit) of the models. We reported the unadjusted prognostic value of individual predictors for pre-eclampsia as odds ratios with 95% confidence and prediction intervals.

RESULTS

The International Prediction of Pregnancy Complications network comprised 78 studies (3,570,993 singleton pregnancies) identified from systematic reviews of tests to predict pre-eclampsia. Twenty-four of the 131 published prediction models could be validated in 11 UK cohorts. Summary C-statistics were between 0.6 and 0.7 for most models, and calibration was generally poor owing to large between-study heterogeneity, suggesting model overfitting. The clinical utility of the models varied between showing net harm to showing minimal or no net benefit. The average discrimination for IPPIC models ranged between 0.68 and 0.83. This was highest for the second-trimester clinical characteristics and biochemical markers model to predict early-onset pre-eclampsia, and lowest for the first-trimester clinical characteristics models to predict any pre-eclampsia. Calibration performance was heterogeneous across studies. Net benefit was observed for International Prediction of Pregnancy Complications first and second-trimester clinical characteristics and clinical characteristics and biochemical markers models predicting any pre-eclampsia, when validated in singleton nulliparous women managed in the UK NHS. History of hypertension, parity, smoking, mode of conception, placental growth factor and uterine artery pulsatility index had the strongest unadjusted associations with pre-eclampsia.

LIMITATIONS

Variations in study population characteristics, type of predictors reported, too few events in some validation cohorts and the type of measurements contributed to heterogeneity in performance of the International Prediction of Pregnancy Complications models. Some published models were not validated because model predictors were unavailable in the individual participant data.

CONCLUSION

For models that could be validated, predictive performance was generally poor across data sets. Although the International Prediction of Pregnancy Complications models show good predictive performance on average, and in the singleton nulliparous population, heterogeneity in calibration performance is likely across settings.

FUTURE WORK

Recalibration of model parameters within populations may improve calibration performance. Additional strong predictors need to be identified to improve model performance and consistency. Validation, including examination of calibration heterogeneity, is required for the models we could not validate.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015029349.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 72. See the NIHR Journals Library website for further project information.

Second trimester maternal serum biomarkers and the risk of cerebral palsy

AIMS

To investigate whether second trimester maternal serum screening (2TMSS) biomarkers are associated with cerebral palsy (CP) and identify CP characteristics associated with abnormal biomarker levels.

METHOD

In this retrospective case-control data linkage study, we linked mothers of 129 singleton CP cases from a population register to their 2TMSS records and selected 10 singleton pregnancy controls per case (n = 1290). We compared mean and abnormal levels of alpha-fetoprotein (AFP), beta subunit of human chorionic gonadotrophin (β-hCG), unconjugated estriol (uE3), and inhibin between cases and controls and within CP subgroups.

RESULTS

Compared to control pregnancies, CP pregnancies had higher mean levels of AFP (1.10 vs. 1.01 multiple of the population median [MoM], p = 0.01) and inhibin (1.10 vs. 0.98 MoM, p ≤ 0.01). CP pregnancies were 2.5 times more likely to be associated with high levels of AFP (OR 2.52 [95% confidence interval [CI] 1.30, 4.65]; p < 0.01) and 2.6 times for inhibin (OR 2.63 [95% CI 1.37, 4.77]; p < 0.01), and 6.8 times when AFP and inhibin were both elevated (OR 6.75 [95% CI 2.41, 18.94]; p < 0.01). In CP cases, high AFP and high inhibin levels were associated with preterm birth and low birthweight.

INTERPRETATION

Abnormal second-trimester biomarker levels suggest abnormal placentation plays a role in the causal pathway of some CP cases.

False-Positive Maternal Serum Screens in the Second Trimester as Markers of Placentally Mediated Complications Later in Pregnancy: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple-marker, maternal serum screening (MSS) has been the cornerstone of prenatal diagnosis since the 1980s. While combinations of these markers are used to predict fetal risk of Down syndrome and other genetic conditions, there is some evidence that individual markers may also predict nongenetic pregnancy complications, particularly those related to placental dysfunction. The objective of this meta-analysis was to investigate the utility of false-positive, second-trimester MSS for Down syndrome as a marker of placentally mediated complications amongst singleton pregnancies globally.

METHODS

Electronic searches of PubMed, Medline, Embase, CINAHL, Web of Science, Scopus, and grey literature to 2019 were performed to identify observational studies comparing risk of pregnancy complications amongst pregnancies with false-positive MSS versus controls. A random-effects model of pooled odds ratios by outcome of interest (stillbirth, preeclampsia, fetal growth restriction, and preterm birth) and subgrouped by type of MSS test (double-, triple-, and quadruple-marker MSS) was used.

RESULTS

16 studies enrolling 68515 pregnancies were included. There were increased odds of preeclampsia (OR 1.28, 95% CI 1.09-1.51) and stillbirth (OR 2.46, 95% CI 1.94-3.12) amongst pregnancies with false-positive MSS. There was no significant association with preterm birth or growth restriction.

CONCLUSIONS

There is some evidence of an association between false-positive, second-trimester MSS for Down syndrome and increased odds of preeclampsia and stillbirth. Future large-scale prospective studies are still needed to best determine the predictive value of false-positive MSS as a marker of placentally mediated complications later in pregnancy and evaluate potential clinical interventions to reduce these risks.

First-trimester maternal serum biomarkers and the risk of cerebral palsy

AIM

To investigate whether combined first-trimester screening (cFTS) biomarkers are associated with cerebral palsy (CP) and to identify CP characteristics associated with abnormal biomarker levels.

METHOD

In this retrospective case-control data linkage study, we matched mothers of 435 singletons with CP from a population register to their cFTS records and selected 10 singleton pregnancy controls per case. We compared mean and abnormal levels (expressed as multiples of the median [MoMs]) of pregnancy-associated plasma protein-A (PAPP-A), beta subunit of human chorionic gonadotrophin (β-hCG), and nuchal translucency between cases and controls and between CP subgroups.

RESULTS

Compared with control pregnancies, CP pregnancies had lower mean levels of PAPP-A (0.95 vs 1.01 MoM, p=0.02) and β-hCG (0.93 vs 0.99 MoM, p=0.02). Biomarker levels in CP pregnancies were 1.8 times more likely to be associated with abnormally low levels of PAPP-A (p<0.01), 1.4 times for β-hCG (p=0.12), and 2.6 times for low PAPP-A and β-hCG together (p=0.04). In cases with CP, an abnormally low PAPP-A level was associated with moderate preterm birth, low Apgar scores, and Gross Motor Function Classification System level V. Low β-hCG was associated with very low birthweight.

INTERPRETATION

Low first-trimester biomarker levels suggest a role for early pregnancy factors in some causal pathways to CP.

WHAT THIS PAPER ADDS

Low first-trimester levels of biomarkers in maternal serum are associated with later cerebral palsy (CP). Early pregnancy factors have potential importance in causal pathways to CP. Causal pathways involving preterm birth, term neonatal encephalopathy, and genetic syndromes may be implicated.

Risk of Severe Maternal Morbidity or Death in Relation to Prenatal Biochemical Screening: Population-Based Cohort Study

OBJECTIVE

This study aimed to examine whether prenatal biochemical screening analytes are associated with an increased risk of severe maternal morbidity (SMM) or maternal mortality.

STUDY DESIGN

This population-based cohort study includes all women in Ontario, Canada, who underwent prenatal screening from 2001 to 2011. Increasing fifth percentiles of the multiple of the median (MoM) for alphafetoprotein (AFP), total human chorionic gonadotropin, unconjugated estriol (uE3), dimeric inhibin-A (DIA), and pregnancy-associated plasma protein A were evaluated. An abnormally high concentration (>95th percentile MoM) for each analyte, individually and combined, was also evaluated. The main outcome assessed was the adjusted relative risk (aRR) of SMM or maternal mortality from 20 weeks' gestation up to 26 weeks thereafter.

RESULTS

Among 748,972 pregnancies, 11,177 resulted in SMM or maternal mortality (1.5%). Except for uE3, the aRR of SMM or maternal mortality increased in association with increasing fifth percentiles of the MoM for all analytes. AFP (aRR: 2.10; 95% confidence interval [CI]: 1.97-2.25) and DIA (aRR: 2.33; 95% CI: 1.98-2.74) > 95th versus ≤ 5th percentile of the MoM were especially associated with SMM or death.

CONCLUSION

Women with abnormally high concentrations of certain prenatal biochemical analytes may be at a higher risk of SMM or death in pregnancy or postpartum.

Risk stratification for early-onset fetal growth restriction in women with abnormal serum biomarkers: a retrospective cohort study

Abnormal maternal serum biomarkers (AMSB), identified through the aneuploidy screening programme, are frequent incidental findings in pregnancy. They are associated with fetal growth restriction (FGR), but previous studies have not examined whether this association is with early-onset (< 34 weeks) or late-onset (> 34 weeks) FGR; as a result there is no consensus on management. The aims of this study were to determine the prevalence and phenotype of FGR in women with AMSB and test the predictive value of placental sonographic screening to predict early-onset FGR. 1196 pregnant women with AMSB underwent a 21-24 week "placental screen" comprising fetal and placental size, and uterine artery Doppler. Multivariable regression was used to calculate a predictive model for early-onset FGR (birthweight centile < 3rd/< 10th with absent umbilical end-diastolic flow, < 34 weeks). FGR prevalence was high (10.3%), however early-onset FGR was uncommon (2.3%). Placental screening effectively identified early-onset (area under the curve (AUC) 0.93, 95% confidence interval (CI) 0.87-1.00), but not late-onset FGR (AUC 0.70, 95% CI 0.64-0.75). Internal validation demonstrated robust performance for detection/exclusion of early-onset FGR. In this cohort, utilisation of our proposed algorithm with targeted fetal growth and Doppler surveillance, compared with universal comprehensive surveillance would have avoided 1044 scans, potentiating significant cost-saving for maternity services.

The Knowledge, Attitude, Practices, and Satisfaction of Non-Invasive Prenatal Testing among Chinese Pregnant Women under Different Payment Schemes: A Comparative Study

Non-invasive prenatal testing (NIPT) for aneuploidy screening has been widely applied across China, and costs can affect Chinese pregnant women’s choices. This study aims to assess the knowledge, attitude, practices (KAP) and satisfaction regarding NIPT among pregnant women in China, and to further explore the relationship between payment schemes and women’s acceptability of and satisfaction with NIPT. A questionnaire survey was performed in Shenzhen and Zhengzhou, China, which separately applied “insurance coverage” and “out-of-pocket” payment scheme for NIPT. The major differences between the two cities were compared using chi-square test, Wilcoxon rank sum test, and propensity score matched analysis. Logistic regression models were applied to explore predictors for women’s acceptability and satisfaction. Compared with Zhengzhou participants, a higher proportion of Shenzhen women had heard of NIPT (87.30% vs. 64.03%), were willing to receive NIPT (91.80% vs. 80.43%) and had taken NIPT (83.12% vs. 54.54%), while their satisfaction level was lower. Having NIPT-related knowledge was associated with higher acceptability, and receiving genetic counseling helped to improve satisfaction. Besides, women with higher annual household incomes were more likely to take and be satisfied with NIPT. In conclusion, more attention should be paid to health education, subsidies for NIPT, and genetic counseling.

The effect of maternal alcohol and drug abuse on first trimester screening analytes: a retrospective cohort study

Background

The purpose of this study was to determine whether first trimester trisomy screening (FTS) parameters are affected by alcohol and drug use.

Methods

A routine combined FTS including measurements of maternal serum levels of free β-human chorionic gonadotropin subunit (free β-hCG) and pregnancy-associated plasma protein A (PAPP-A) were measured at 9–11 weeks of gestation, and fetal nuchal translucency thickness (NTT) at 11–13 weeks of gestation. In total 544 women with singleton pregnancies [71 alcohol and drug abusers, 88 smokers, 168 non-smokers delivering a small for gestational age (SGA) child, and 217 unexposed control women] were assessed.

Results

Free β-hCG levels were higher in alcohol and drug abusing than in unexposed pregnant women [mean 1.5 vs. 1.2 multiples of medians (MoM); P = 0.013]. However, stepwise multiple linear regression analyses suggested that smoking could explain increased free β-hCG. Additionally, we observed lower PAPP-A levels in the smoking mothers (0.9 vs. 1.2 MoM; P = 0.045) and in those giving birth to an SGA child compared to the controls (1.1 vs.. 1.2 MoM; P < 0.001). Fetal NTT did not differ significantly between any of the groups.

Conclusions

The present study shows increased free β-hCG levels in alcohol and drug abusers, but maternal smoking may explain the result. Maternal serum PAPP-A levels were lower in smoking than non-smoking mothers, and in mothers delivering an SGA child. However, FTS parameters (PAPP-A, free β-hCG and NTT) seem not to be applicable for the use as alcohol biomarkers because of their clear overlap between alcohol abusers and healthy controls.

Tracking placental development in health and disease

Pre-eclampsia and fetal growth restriction arise from disorders of placental development and have some shared mechanistic features. Initiation is often rooted in the maldevelopment of a maternal-placental blood supply capable of providing for the growth requirements of the fetus in later pregnancy, without exerting undue stress on maternal body systems. Here, we review normal development of a placental bed with a safe and adequate blood supply and a villous placenta-blood interface from which nutrients and oxygen can be extracted for the growing fetus. We consider disease mechanisms that are intrinsic to the maternal environment, the placenta or the interaction between the two. Systemic signalling from the endocrine placenta targets the maternal endothelium and multiple organs to adjust metabolism for an optimal pregnancy and later lactation. This signalling capacity is skewed when placental damage occurs and can deliver a dangerous pathogenic stimulus. We discuss the placental secretome including glycoproteins, microRNAs and extracellular vesicles as potential biomarkers of disease. Angiomodulatory mediators, currently the only effective biomarkers, are discussed alongside non-invasive imaging approaches to the prediction of disease risk. Identifying the signs of impending pathology early enough to intervene and ameliorate disease in later pregnancy remains a complex and challenging objective.

Prenatal Biochemical Screening and a Woman’s Long-Term Risk of Cancer: A Population-Based Cohort Study

Background

Some hormones measured in pregnancy are linked to certain hormone-sensitive cancers. We investigated whether routine serum screening in pregnancy is associated with a woman’s subsequent risk of hormone-sensitive cancer.

Methods

This population-based cohort study included women aged 12–55 years who underwent prenatal screening between 11 weeks + 0 days of gestation to 20 weeks + 6 days of gestation in Ontario, Canada, 1993–2011, where universal health care is available. The hazard ratio of newly diagnosed breast, ovarian, endometrial, and thyroid cancer—arising at 21 weeks + 0 days of gestation or thereafter—was estimated in association with an abnormally low (≤5th) or high (>95th) percentile multiple of the median (MoM) for alpha-fetoprotein (AFP), total human chorionic gonadotropin (hCG), unconjugated estriol, pregnancy-associated plasma protein A, and dimeric inhibin A.

Results

Among 677 247 pregnant women followed for a median of 11.0 years (interquartile range = 7.5–16.1), 7231 (1.07%) developed breast cancer, 515 (0.08%) ovarian cancer, 508 (0.08%) endometrial cancer, and 4105 (0.61%) thyroid cancer. In multivariable adjusted models, abnormally high hCG greater than the 95th percentile MoM was associated with a doubling in the risk of endometrial cancer (adjusted hazard ratio [aHR] = 1.98, 95% confidence interval [CI] = 1.33 to 2.95), and abnormally low AFP at the fifth percentile or less MoM conferred a moderately greater risk of thyroid cancer (aHR = 1.21, 95% CI = 1.07 to 1.38). Abnormally low pregnancy-associated plasma protein A at the fifth percentile or less MoM was not statistically significantly associated with breast cancer after multivariable adjustment (aHR = 1.19, 95% CI = 0.98 to 1.36).

Conclusions

Women with abnormally high levels of serum hCG or low AFP in early pregnancy may be at a greater future risk of certain types of hormone-sensitive cancers.

Blood-based biomarkers in the maternal circulation associated with fetal growth restriction

Fetal growth restriction (FGR) is associated with threefold to fourfold increased risk of stillbirth. Identifying FGR, through its commonly used surrogate-the small-for-gestational-age (SGA, estimated fetal weight and/or abdominal circumference <10th centile) fetus-and instituting fetal surveillance and timely delivery decrease stillbirth risk. Methods available to clinicians for antenatal identification of SGA fetuses have surprisingly poor sensitivity. About 80% of cases remain undetected. Measuring the symphysis-fundal height detects only 20% of SGA fetuses, and even universal third trimester ultrasound detects, at best, 57% of those born SGA. There is an urgent need to find better ways to identify this at-risk cohort. This review summarises efforts to identify molecular biomarkers (proteins, metabolites, or ribonucleic acids) that could be used to better predict FGR. Most studies examining potential biomarkers to date have utilised case-control study designs without proceeding to validation in independent cohorts. To develop a robust test for FGR, large prospective studies are required with a priori validation plans and cohorts. Given that current clinical care detects 20% of SGA fetuses, even a screening test with ≥60% sensitivity at 90% specificity could be clinically useful, if developed. This may be an achievable aspiration. If discovered, such a test may decrease stillbirth.

Prediction of pre-eclampsia: review of reviews

OBJECTIVE

Primary studies and systematic reviews provide estimates of varying accuracy for different factors in the prediction of pre-eclampsia. The aim of this study was to review published systematic reviews to collate evidence on the ability of available tests to predict pre-eclampsia, to identify high-value avenues for future research and to minimize future research waste in this field.

METHODS

MEDLINE, EMBASE and The Cochrane Library including DARE (Database of Abstracts of Reviews of Effects) databases, from database inception to March 2017, and bibliographies of relevant articles were searched, without language restrictions, for systematic reviews and meta-analyses on the prediction of pre-eclampsia. The quality of the included reviews was assessed using the AMSTAR tool and a modified version of the QUIPS tool. We evaluated the comprehensiveness of search, sample size, tests and outcomes evaluated, data synthesis methods, predictive ability estimates, risk of bias related to the population studied, measurement of predictors and outcomes, study attrition and adjustment for confounding.

RESULTS

From 2444 citations identified, 126 reviews were included, reporting on over 90 predictors and 52 prediction models for pre-eclampsia. Around a third (n = 37 (29.4%)) of all reviews investigated solely biochemical markers for predicting pre-eclampsia, 31 (24.6%) investigated genetic associations with pre-eclampsia, 46 (36.5%) reported on clinical characteristics, four (3.2%) evaluated only ultrasound markers and six (4.8%) studied a combination of tests; two (1.6%) additional reviews evaluated primary studies investigating any screening test for pre-eclampsia. Reviews included between two and 265 primary studies, including up to 25 356 688 women in the largest review. Only approximately half (n = 67 (53.2%)) of the reviews assessed the quality of the included studies. There was a high risk of bias in many of the included reviews, particularly in relation to population representativeness and study attrition. Over 80% (n = 106 (84.1%)) summarized the findings using meta-analysis. Thirty-two (25.4%) studies lacked a formal statement on funding. The predictors with the best test performance were body mass index (BMI) > 35 kg/m² , with a specificity of 92% (95% CI, 89-95%) and a sensitivity of 21% (95% CI, 12-31%); BMI > 25 kg/m² , with a specificity of 73% (95% CI, 64-83%) and a sensitivity of 47% (95% CI, 33-61%); first-trimester uterine artery pulsatility index or resistance index > 90^th centile (specificity 93% (95% CI, 90-96%) and sensitivity 26% (95% CI, 23-31%)); placental growth factor (specificity 89% (95% CI, 89-89%) and sensitivity 65% (95% CI, 63-67%)); and placental protein 13 (specificity 88% (95% CI, 87-89%) and sensitivity 37% (95% CI, 33-41%)). No single marker had a test performance suitable for routine clinical use. Models combining markers showed promise, but none had undergone external validation.

CONCLUSIONS

This review of reviews calls into question the need for further aggregate meta-analysis in this area given the large number of published reviews subject to the common limitations of primary predictive studies. Prospective, well-designed studies of predictive markers, preferably randomized intervention studies, and combined through individual-patient data meta-analysis are needed to develop and validate new prediction models to facilitate the prediction of pre-eclampsia and minimize further research waste in this field. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

The association between first trimester AFP to PAPP-A ratio and placentally-related adverse pregnancy outcome

INTRODUCTION

Low maternal serum levels of pregnancy-associated plasma protein A (PAPP-A) measured in the first trimester and high levels of alpha fetoprotein (AFP) measured in the second trimester have been associated with adverse pregnancy outcomes reflective of placental insufficiency, and there is a synergistic relationship between the two. We investigated the utility as a screening test of a simple ratio of maternal serum AFP to PAPP-A (AFP:PAPP-A) measured in the first trimester.

METHODS

We studied 4057 nulliparous women with a singleton pregnancy from the Pregnancy Outcome Prediction (POP) study. We studied the predictive ability for adverse outcome of the AFP:PAPP-A ratio measured in the first trimester with and without correction for maternal weight and gestational age at measurement. We compared the AFP:PAPP-A ratio with corrected AFP and PAPP-A on their own and in combination.

RESULTS

An AFP:PAPP-A ratio >10 was associated with placentally-related adverse outcomes, including fetal growth restriction (risk ratio (RR) 3.74, 95% confidence interval (CI) 2.30-6.09), severe preeclampsia (RR 2.12, 95% CI 1.39-3.25) and stillbirth (RR 5.05, 95% CI 1.48-17.18). The ratio performed favorably in predicting adverse pregnancy outcomes when compared with corrected measurements of either AFP or PAPP-A, and was equivalent to a model combining the two. Its predictive ability was not affected by correction for maternal weight or gestational age at measurement.

DISCUSSION

An elevated maternal AFP:PAPP-A ratio in the first trimester is associated with placentally-related adverse outcomes in a cohort of unselected nulliparous women.

The untapped potential of placenta-enriched molecules for diagnostic and therapeutic development

Pregnancy complications such as fetal growth restriction and preeclampsia are diseases with limited biomarkers for prediction, and a complete lack of therapeutic options. We define placenta-enriched molecules as those that are highly expressed in the placenta relative to all other human tissues. Many exist including mRNAs, miRNAs and proteins. It is now well established that placenta-enriched mRNAs are found within the maternal circulation and are cleared rapidly after birth. Similarly, distinct clusters of miRNAs that are placenta-enriched have been identified and are measurable within the circulation. However, perhaps the most established potential diagnostics thus far are circulating placental proteins such as placental growth factor (PlGF), pregnancy associated pregnancy protein-A (PAPP-A) and soluble FMS-like tyrosine kinase 1 (sFlt-1). There has also been much interest in targeting placenta-enriched molecules as a means to treat diseases of pregnancy. We have shown promising results in targeting placenta-enriched epidermal growth factor receptor (EGFR) to treat ectopic pregnancy. Others have focused on using placenta-enriched molecules as a means of homing therapeutic-filled nanoparticles to the placenta, or to directly target sFlt-1 to improve disease outcomes. Importantly, many placenta-enriched molecules remain largely unstudied. We propose that a better understanding of their biology, and potential contribution to the pathogenesis of diseases, may yield more predictive diagnostic and therapeutic targets.

Knowledge Gaps and Emerging Research Areas in Intrauterine Growth Restriction-Associated Brain Injury

Intrauterine growth restriction (IUGR) is a complex global healthcare issue. Concerted research and clinical efforts have improved our knowledge of the neurodevelopmental sequelae of IUGR which has raised the profile of this complex problem. Nevertheless, there is still a lack of therapies to prevent the substantial rates of fetal demise or the constellation of permanent neurological deficits that arise from IUGR. The purpose of this article is to highlight the clinical and translational gaps in our knowledge that hamper our collective efforts to improve the neurological sequelae of IUGR. Also, we draw attention to cutting-edge tools and techniques that can provide novel insights into this disorder, and technologies that offer the potential for better drug design and delivery. We cover topics including: how we can improve our use of crib-side monitoring options, what we still need to know about inflammation in IUGR, the necessity for more human post-mortem studies, lessons from improved integrated histology-imaging analyses regarding the cell-specific nature of magnetic resonance imaging (MRI) signals, options to improve risk stratification with genomic analysis, and treatments mediated by nanoparticle delivery which are designed to modify specific cell functions.

Prenatal biochemical screening and long term risk of maternal cardiovascular disease: population based cohort study

OBJECTIVE

To examine whether abnormal prenatal biochemical screening results are associated with an increased risk of premature cardiovascular disease after pregnancy.

DESIGN

Population based cohort study.

SETTING

The entire province of Ontario, Canada, where healthcare is universally available.

PARTICIPANTS

Women aged 12-55 years, without pre-existing cardiovascular disease, who underwent prenatal screening between 1993 and 2011. One pregnancy per woman was randomly selected.

EXPOSURES

Low (≤5th centile multiple of the median) serum total chorionic gonadotropin, unconjugated estriol, and pregnancy associated plasma protein A and high (≥95th centile multiple of the median) alphafetoprotein and dimeric inhibin-A.

MAIN OUTCOME MEASURES

Composite of hospital admission or revascularisation for coronary artery, cerebrovascular, or peripheral arterial disease or hospital admission for heart failure or dysrhythmia at least 365 days after pregnancy.

RESULTS

Among 855 536 pregnancies, and after a median of 11.4 (interquartile range 6.8-17.5) years of follow-up, 6209 women developed the main cardiovascular disease outcome. Abnormal results for each of the five prenatal biochemical screening analytes, especially dimeric inhibin-A, were associated with a higher risk of cardiovascular disease. Women with an abnormally high dimeric inhibin-A (≥95th centile) had the highest rate of cardiovascular disease (30 events or 8.3 per 10 000 person years versus 251 events or 3.8 per 10 000 person years for those <95th centile; multivariable adjusted hazard ratio 2.0, 95% confidence interval 1.4 to 3.0). Compared with women without any abnormal biochemical measure, the hazard ratio for the cardiovascular disease composite outcome was 1.2-1.3 times higher with one abnormal analyte and 1.5-2.0 times higher with two or more abnormal analytes.

CONCLUSIONS

Women with abnormal prenatal biochemical screening results, especially for dimeric inhibin-A, may be at higher risk of cardiovascular disease. If these findings are replicated elsewhere, a massive amount of data exists that could aid in identifying women at higher risk of premature cardiovascular disease and that could be conveyed to them or their healthcare providers.

Performance of first trimester biochemical markers and mean arterial pressure in prediction of early-onset pre-eclampsia

OBJECTIVE

To develop a predictive risk model for early-onset pre-eclampsia (EO-PE) using maternal characteristics, combined screening markers, previously reported biomarkers for PE and mean arterial pressure (MAP).

METHODS

This retrospective study was conducted at Oulu University hospital between 2006 and 2010. Maternal serum from first trimester combined screening was further analyzed for alpha fetoprotein (AFP), placental growth factor (PlGF), soluble tumor necrosis factor receptor-1 (sTNFR1), retinol binding protein-4 (RBP4), a disintegrin and metalloprotease-12 (ADAM12), soluble P-selectin (sP-selectin), follistatin like-3 (FSTL3), adiponectin, angiopoietin-2 (Ang-2) and sex hormone binding globulin (SHBG). First, the training sample set with 29 cases of EO-PE and 652 controls was developed to study whether these biomarkers separately or in combination with prior risk (maternal characteristics, first trimester pregnancy associated plasma protein-A (PAPP-A) and free beta human chorionic gonadotrophin (fβ-hCG)) could be used to predict the development of EO-PE. Second, the developed risk models were validated with a test sample set of 42 EO-PE and 141 control subjects. For the test set MAP data was also available.

RESULTS

Single marker statistically significant (ANOVA p<0.05) changes between control and EO-PE pregnancies were observed with AFP, RBP4 and sTNFR1 with both training and test sample sets. Based on the test sample set performances, the best detection rate, 47% for a 10% false positive rate, was achieved with PlGF and sTNFR1 added with prior risk and MAP.

CONCLUSION

Based on our results, the best first trimester biomarkers to predict the subsequent EO-PE were AFP, PlGF, RBP4 and sTNFR1. The risk models that performed best for the prediction of EO-PE included prior risk, MAP, sTNFR1 and AFP or PlGF or RBP4.

Recurrence of extreme serum analytes in consecutive pregnancies and association with obstetrical outcomes. J Matern Fetal Neonatal Med 2017;32:85-91. [PMID: 28838266 DOI: 10.1080/14767058.2017.1371695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

OBJECTIVE

To evaluate if presence of extreme maternal serum biochemical analytes recurs in consecutive pregnancies. We hypothesized that presence of >1 extreme analyte in prior pregnancy is associated with increased risk of adverse pregnancy outcome in subsequent pregnancy.

METHODS

Retrospective cohort study of singleton pregnancies evaluated and delivered in 2 consecutive pregnancies (2011-2015). Adverse outcomes were defined as indicated preterm delivery before 37 completed weeks due to preeclampsia, fetal growth restriction or other complications.

RESULTS

First and second trimester maternal serum analytes were assessed in 1434 patients in 2 consecutive pregnancies. The presence of >1 extreme serum analyte in prior pregnancy significantly increased likelihood of >1 extreme analyte in subsequent pregnancy. The likelihood increased as number of prior extreme markers increased. In patients with normal outcomes and 2 or more extreme serum analytes in prior pregnancy, there was an increased incidence of adverse pregnancy outcomes in subsequent pregnancy with relative risk (RR) of 5.42 [95% CI 1.6-18.3].

CONCLUSIONS

The presence of more than 1 extreme serum marker in one pregnancy increases likelihood of recurrence in subsequent pregnancies. Risk of adverse outcomes in subsequent pregnancy can be evaluated based on biochemistry results as well as prior pregnancy outcomes.

Association of maternal serum PAPP-A levels, nuchal translucency and crown-rump length in first trimester with adverse pregnancy outcomes: retrospective cohort study

OBJECTIVE

Are first trimester serum pregnancy-associated plasma protein-A (PAPP-A), nuchal translucency (NT) and crown-rump length (CRL) prognostic factors for adverse pregnancy outcomes?

METHOD

Retrospective cohort, women, singleton pregnancies (UK 2011-2015). Unadjusted and multivariable logistic regression.

OUTCOMES

small for gestational age (SGA), pre-eclampsia (PE), preterm birth (PTB), miscarriage, stillbirth, perinatal mortality and neonatal death (NND).

RESULTS

A total of 12 592 pregnancies: 852 (6.8%) PTB, 352 (2.8%) PE, 1824 (14.5%) SGA, 73 (0.6%) miscarriages, 37(0.3%) stillbirths, 73 perinatal deaths (0.6%) and 38 (0.30%) NND. Multivariable analysis: lower odds of SGA [adjusted odds ratio (aOR) 0.88 (95% CI 0.85,0.91)], PTB [0.92 (95%CI 0.88,0.97)], PE [0.91 (95% CI 0.85,0.97)] and stillbirth [0.71 (95% CI 0.52,0.98)] as PAPP-A increases. Lower odds of SGA [aOR 0.79 (95% CI 0.70,0.89)] but higher odds of miscarriage [aOR 1.75 95% CI (1.12,2.72)] as NT increases, and lower odds of stillbirth as CRL increases [aOR 0.94 95% CI (0.89,0.99)]. Multivariable analysis of three factors together demonstrated strong associations: a) PAPP-A, NT, CRL and SGA, b) PAPP-A and PTB, c) PAPP-A, CRL and PE, d) NT and miscarriage.

CONCLUSIONS

Pregnancy-associated plasma protein-A, NT and CRL are independent prognostic factors for adverse pregnancy outcomes, particularly PAPP-A and SGA with lower PAPP-A associated with increased risk. © 2017 John Wiley & Sons, Ltd.

External validation, update and development of prediction models for pre-eclampsia using an Individual Participant Data (IPD) meta-analysis: the International Prediction of Pregnancy Complication Network (IPPIC pre-eclampsia) protocol

BACKGROUND

Pre-eclampsia, a condition with raised blood pressure and proteinuria is associated with an increased risk of maternal and offspring mortality and morbidity. Early identification of mothers at risk is needed to target management.

METHODS/DESIGN

We aim to systematically review the existing literature to identify prediction models for pre-eclampsia. We have established the International Prediction of Pregnancy Complication Network (IPPIC), made up of 72 researchers from 21 countries who have carried out relevant primary studies or have access to existing registry databases, and collectively possess data from more than two million patients. We will use the individual participant data (IPD) from these studies to externally validate these existing prediction models and summarise model performance across studies using random-effects meta-analysis for any, late (after 34 weeks) and early (before 34 weeks) onset pre-eclampsia. If none of the models perform well, we will recalibrate (update), or develop and validate new prediction models using the IPD. We will assess the differential accuracy of the models in various settings and subgroups according to the risk status. We will also validate or develop prediction models based on clinical characteristics only; clinical and biochemical markers; clinical and ultrasound parameters; and clinical, biochemical and ultrasound tests.

DISCUSSION

Numerous systematic reviews with aggregate data meta-analysis have evaluated various risk factors separately or in combination for predicting pre-eclampsia, but these are affected by many limitations. Our large-scale collaborative IPD approach encourages consensus towards well developed, and validated prognostic models, rather than a number of competing non-validated ones. The large sample size from our IPD will also allow development and validation of multivariable prediction model for the relatively rare outcome of early onset pre-eclampsia.

TRIAL REGISTRATION

The project was registered on Prospero on the 27 November 2015 with ID: CRD42015029349.

Altered Biomarkers in Trophoblast Cells Obtained Noninvasively Prior to Clinical Manifestation of Perinatal Disease

A contributing factor to poor placental perfusion, leading to intrauterine growth restriction and preeclampsia, is the failure of invading extravillous trophoblast (EVT) cells to remodel the maternal uterine arteries during the first and second trimesters of pregnancy. Noninvasive assessment of EVT cells in ongoing pregnancies is possible beginning three weeks after conception, using trophoblast retrieval and isolation from the cervix (TRIC). Seven proteins were semi-quantified by immunofluorescence microscopy in EVT cells obtained between gestational weeks 6 and 20 from pregnancies with normal outcomes (N = 29) and those with intrauterine growth restriction or preeclampsia (N = 12). Significant differences were measured in expression of PAPPA, FLT1, ENG, AFP, PGF, and LGALS14, but not LGALS13 or the lineage marker KRT7. These findings provide for the first time direct evidence of pathology-associated protein dysregulation in EVT cells during early placentation. The TRIC platform provides a novel approach to acquire molecular signatures of EVT cells that can be correlated with pregnancy outcome.

Predictive values of maternal serum PAPP-A level, uterine artery Doppler velocimetry, and fetal biometric measurements for poor pregnancy and poor neonatal outcomes in pregnant women

OBJECTIVE

To determine predictive values of maternal serum PAPP-A (msPAPP-A) levels, uterine artery Doppler velocimetry, and fetal biometric measurements (FBMs) for poor pregnancy and poor neonatal outcomes.

MATERIAL AND METHODS

This prospective cohort study was conducted on singleton pregnancies followed until delivery. Pregnancy and neonatal outcomes were evaluated with respect to the msPAPP-A level at the 11(th)-14(th) weeks, uterine artery Doppler velocimetry at the 15(th)-18(th) weeks, and FBMs at the 20(th)-24(th) and 28(th)-32(nd) weeks of pregnancy.

RESULTS

One hundred fifty-eight women constituted the study group; 17 (10.75%) of them had at least one poor pregnancy outcome. The cut-off point of 0.72 multiple of the median (MoM) for the PAPP-A level achieved a sensitivity of 82.4% and a specificity of 29.8% for poor pregnancy outcomes. The mean birth weight was significantly lower in the subgroup with a higher mean pulsatility index of uterine arteries (UAPImean≥1.19) (p=0.025) as well as in the subgroup with a higher mean resistance index of uterine arteries (UARImean≥0.62) (p=0.013). When the subgroup of pregnant women under the risk of early-onset IUGR according to FBMs was compared to the low-risk group, statistically significant differences were seen in terms of pregnancy outcomes (p=0.045) and birth weight (p=0.011).

CONCLUSION

Maternal serum PAPP-A level and FBMs could be used for predicting pregnancy outcomes, while uterine artery Doppler velocimetry and FBMs could be used for predicting neonatal outcomes, specifically the birth weight.

Investigation on the ability of first trimester glycodelin and angiopoietin-2 to predict small-for-gestational age pregnancies at delivery

BACKGROUND

The aim was to investigate whether first trimester glycodelin and angiopoietin-2 can predict small-for-gestational age (SGA) at delivery, individually or in combination.

METHODS

In this case-control study we measured glycodelin and angiopoietin-2 on serum from 170 singleton pregnant women delivering SGA neonates and 985 singleton pregnant women delivering normal-weighted neonates. All values were converted to multiples of the medians (MoM).

RESULTS

Pregnant women delivering SGA neonates had lower first trimester glycodelin and angiopoietin-2 MoM values [median (interquartile range)] compared with pregnant women delivering normal-weighted neonates for glycodelin: 0.86 (0.58-1.24) vs. 1.03 (0.74-1.45), p<0.001, and for angiopoietin-2: 0.89 (0.69-1.19) vs. 1.01 (0.78-1.31), p<0.001. The prediction performances of the biomarkers showed that the areas under the curve (AUC) were 0.59 (glycodelin), 0.58 (angiopoietin-2), and 0.60 (glycodelin and angiopoietin-2).

CONCLUSIONS

We demonstrated that first trimester glycodelin and angiopoietin-2 were associated with SGA, but they were, individually and in combination, poor predictors of SGA at delivery. The AUCs were low which indicate low detection rates and high false positive rates.

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.

Maternal serum alpha-fetoprotein at 12, 22 and 32 weeks' gestation in screening for pre-eclampsia

OBJECTIVE

To examine the distribution of maternal serum alpha-fetoprotein (AFP) at 12, 22 and 32 weeks' gestation in singleton pregnancies which develop pre-eclampsia (PE) and examine the performance of this biomarker in screening for PE.

METHODS

Serum AFP was measured in 17 071 cases at 11-13 weeks, in 8583 cases at 19-24 weeks and 8609 cases at 30-34 weeks' gestation. Bayes' theorem was used to combine the a-priori risk from maternal characteristics and medical history with AFP. The performance of screening for PE requiring delivery < 32, at 32 + 0 to 36 + 6, < 37 and ≥ 37 weeks' gestation was estimated.

RESULTS

In pregnancies that developed PE, serum AFP multiples of the median (MoM) was increased at 11-13 and 19-24 weeks' gestation, but not at 30-34 weeks, and the values were inversely related to gestational age at delivery. Combined screening with maternal factors and serum AFP improved the prediction provided by maternal factors alone for PE delivering < 37 weeks, but not for PE delivering ≥ 37 weeks. The performance of screening for preterm PE was better at 19-24 weeks than at 11-13 weeks and the detection rate (DR) for a given false-positive rate (FPR) was higher for PE delivering < 32 weeks than for PE delivering at 32 + 0 to 36 + 6 weeks. The DRs, at 10% FPR, of combined screening at 11-13 weeks for PE delivering < 32 and at 32 + 0 to 36 + 6 weeks were 54% and 45%, respectively, and these improved to 72% and 53% with screening at 19-24 weeks.

CONCLUSIONS

Measurement of serum AFP at 11-13 and 19-24 weeks' gestation improves the prediction of preterm PE provided by maternal factors alone. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Maternal Serum Analytes as Predictors of Fetal Growth Restriction with Different Degrees of Placental Vascular Dysfunction

Abnormal levels of maternal serum analytes have been associated with fetal growth restriction (FGR) and preeclampsia secondary to placental vascular dysfunction. Accurately identifying the FGR fetuses at highest risk for adverse outcomes remains challenging. Placental function can be assessed by Doppler analysis of the maternal and fetal circulation. Although the combination of multiple abnormal maternal serum analytes and abnormal Doppler findings is strongly associated with adverse outcomes, the predictive value remains too low to be used as a screening test in a low-risk population. Stratification of cases based on the severity of Doppler abnormalities may improve predictive models.

Maternal Serum Aneuploidy Screen and Adverse Pregnancy Outcomes

OBJECTIVE

To find out whether maternal serum screening for fetal chromosomal aneuploidy predicts adverse pregnancy outcomes.

METHODS

A two-year retrospective case-control study was conducted at a tertiary hospital. Pregnant women with a high-risk serum screen but with chromosomally normal fetuses (n = 189) were compared to those with low-risk screen (controls, n = 157) for adverse pregnancy outcomes.

RESULTS

Women with high-risk double marker or combined screen were found to have higher prevalence of LBW [OR 2.56; 95 % CI (1.01-6.53), p < 0.05] and PT [OR 2.93; 95 % CI (1.11-7.65), p < 0.05], while women with high-risk triple screen had higher prevalence of PIH [OR 3.72; 95 % CI (1.23-11.18); p < 0.05], Oligo [OR 4.50; 95 % CI (1.30-15.64); p < 0.05], delivery by C-section [OR 2.51; 95 % CI (1.41-4.47); p < 0.005] as compared to low-risk women. PAPP-A was found to be a significant predictor of birth weight (R (2) = 12.2 %, β ± SE = 0.224 ± 0.069; p < 0.005) and gestational age (R (2) = 4.9 %, β ± SE = 0.613 ± 0.296; p < 0.05). Beta hCG in first and hCG in second trimester predicted oligohydramnios (R (2) = 9.2 %, β ± SE = -0.077 ± 0.025; p < 0.005). The areas under the ROC curves of PAPP-A for LBW and PT were 0.70(p < 0.01) and 0.684 (p < 0.05), respectively.

CONCLUSION

A "high-risk" maternal serum screen with abnormal PAPP-A and/or beta hCG/HCG is associated with adverse pregnancy outcomes and may help identifying women requiring additional fetal surveillance.

Global burden of genetic disease and the role of genetic screening

It is estimated that 5.3% of newborns will suffer from a genetic disorder, when followed up until the age of 25 years. In developing, as compared to western countries, hemoglobinopathies and glucose-6-phosphate dehydrogenase deficiency have a higher incidence due to severe falciparum malaria in the distant past, and autosomal recessive disorders have a higher frequency due to greater proportion of consanguineous marriages. Chromosomal disorders have a combined frequency of 1 in 153 births, therefore screening for chromosomal disorders is essential, using biochemical markers, ultrasonography, and recently by non-invasive prenatal diagnosis based on cell-free fetal DNA in maternal plasma. Preconceptional counseling should be encouraged. For genetic disorders screening should be carried out, ideally after marriage, but before pregnancy. The disorders to be screened depend upon ethnicity. Metabolic disorders have a high incidence in developing countries due to greater rate of consanguineous marriages. Newborn screening is recommended to reduce the burden of these disorders, as many metabolic disorders can be treated. Hearing and critical congenital heart disease should both be screened in the newborn period.

Prediction of small-for-gestational-age neonates: screening by maternal serum biochemical markers at 19-24 weeks

OBJECTIVE

To investigate the value of maternal serum concentrations of placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (β-hCG) and α-fetoprotein (AFP) at 19-24 weeks' gestation, in combination with maternal factors and fetal biometry, in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE) and examine the potential value of such assessment in deciding whether the third-trimester scan should be performed at 32 and/or 36 weeks' gestation.

METHODS

This was a screening study in 9715 singleton pregnancies, including 481 (5.0%) that delivered SGA neonates with birth weight < 5(th) percentile (SGA < 5(th) ), in the absence of PE. Multivariable logistic regression analysis was used to determine if screening by a combination of maternal factors, Z-scores of fetal head circumference, abdominal circumference and femur length, and log10 multiples of the median (MoM) values of PlGF, sFlt-1, PAPP-A, free β-hCG or AFP had a significant contribution to the prediction of SGA neonates. A model was developed in selecting the gestational age for third-trimester assessment, at 32 and/or 36 weeks, based on the results of screening at 19-24 weeks.

RESULTS

Compared to the normal group, the mean log10 MoM value of PlGF was lower, AFP was higher and sFlt-1, PAPP-A and free β-hCG were not significantly different in the SGA < 5(th) group that delivered < 37 weeks. The detection rate (DR) of combined screening by maternal factors, fetal biometry and serum PlGF and AFP at 19-24 weeks was 100%, 76% and 38% for SGA < 5(th) delivering < 32, 32-36 and ≥ 37 weeks' gestation, respectively, at a false-positive rate (FPR) of 10%. In a hypothetical model, it was estimated that, if the desired objective of prenatal screening is to predict about 80% of the cases of SGA < 5(th) , it would be necessary to select 11% of the population at the 19-24-week assessment to be reassessed at 32 weeks and 46% to be reassessed at 36 weeks; 54% would not require a third-trimester scan.

CONCLUSION

Prenatal prediction of a high proportion of SGA neonates necessitates the undertaking of screening in the third trimester of pregnancy, in addition to assessment in the second trimester, and the timing of such screening, at 32 and/or 36 weeks, should be contingent on the results of the assessment at 19-24 weeks.

Association between isolated abnormal levels of maternal serum unconjugated estriol in the second trimester and adverse pregnancy outcomes

OBJECTIVE

To determine the association between maternal serum unconjugated estriol (uE3) levels in the second trimester and adverse pregnancy outcomes.

PATIENTS AND METHODS

The prospective database of our fetal Down screening program was assessed and reviewed for maternal serum uE3 levels. Pregnancies with medical diseases, abnormal levels of beta-human chorionic gonadotropin, alpha-fetoprotein and fetal chromosomal or structural abnormalities were excluded. The recruited women were categorized into three groups: high (>95th percentile), normal (5-95th percentile) and low (<5th percentile) uE3 levels.

RESULTS

Of 14 212 screened women, 9183 (high; 455, normal; 8271 and low; 457) levels group, were available for outcome analysis. The rates of most adverse outcomes, including preterm birth, low Apgar scores, fetal death, placental abruption, preeclampsia and gestational diabetes mellitus, of the high and normal groups were comparable. Nevertheless, low uE3 levels increased risk of fetal growth restriction (FGR) (RR: 2.36, 95% CI: 1.79-3.10) and low birth weight (LBW) (RR: 1.87, 95% CI: 1.45-2.39), but not preterm birth. Logistic regression analysis indicated that low uE3 level was an independent risk factor for FGR and LBW.

CONCLUSIONS

High uE3 levels in the second trimester are not associated with poor outcomes, whereas low levels significantly increase risk of FGR and LBW but not other adverse outcomes.

Predictive Value of Free β-hCG Multiple of the Median for Women with Preeclampsia

BACKGROUND

Preeclampsia (PE) is relatively common and is unpredictable in its onset and progression.

AIMS

We investigated the clinical value of using the multiple of the median (MoM) of free β-human chorionic gonadotropin (β-hCG) concentrations in women with normal pregnancy and PE.

METHODS

This study was based on a dataset available from published studies, and the relevant studies were retrieved from multiple electronic databases. Data were extracted from case-control studies; a random-effects model was employed, and standardized mean difference and 95% confidence intervals were calculated. Twelve case-control studies (eleven English-based articles and one Chinese-based article) were analyzed in the current meta-analysis and included 702 patients with PE and 8,233 women with normal pregnancies.

RESULTS

Statistical analysis revealed a higher MoM of β-hCG serum levels in patients with PE. Ethnicity subgroup analysis showed that the MoM of serum β-hCG levels was significantly higher in women with PE in both Asian and Caucasian populations.

CONCLUSION

The MoM of β-hCG serum levels was significantly increased in women with PE compared to women with normal pregnancies. Screening for serum β-hCG MoM levels will be helpful in the early identification of pregnancies at risk of developing PE. © 2015 S. Karger AG, Basel.

Prediction of small-for-gestational-age neonates: screening by maternal biochemical markers at 30-34 weeks

OBJECTIVE

To investigate the potential value of serum placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (β-hCG) and α-fetoprotein (AFP) at 30-34 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE).

METHODS

This was a screening study in singleton pregnancies at 30-34 weeks' gestation, including 490 that delivered SGA neonates and 9360 cases that were unaffected by SGA, PE or gestational hypertension (normal outcome). Multivariable logistic regression analysis was used to determine if screening by serum PlGF, sFlt-1, PAPP-A, free β-hCG and AFP, individually or in combination, improved the prediction of SGA neonates provided by screening with maternal characteristics and medical history (maternal factors), and estimated fetal weight (EFW) from fetal head circumference, abdominal circumference and femur length.

RESULTS

Compared to the normal group, the mean log10 multiples of the median (MoM) values of PlGF and AFP were significantly lower and the mean log10 MoM values of sFlt-1 and free β-hCG were significantly higher in the SGA group with a birth weight < 5(th) percentile (SGA < 5(th)) delivering < 5 weeks following assessment. The best model for prediction of SGA was provided by a combination of maternal factors, EFW and serum PlGF. Such combined screening, predicted, at a 10% false-positive rate, 85%, 93% and 92% of SGA neonates delivering < 5 weeks following assessment with birth weight < 10(th), < 5(th) and < 3(rd) percentiles, respectively; the respective detection rates of combined screening for SGA neonates delivering ≥ 5 weeks following assessment were 57%, 64% and 71%.

CONCLUSION

Combined screening by maternal factors, EFW and serum PlGF at 30-34 weeks' gestation can identify a high proportion of pregnancies that subsequently deliver SGA neonates.

Could first-trimester assessment of placental functions predict preeclampsia and intrauterine growth restriction? A prospective cohort study

OBJECTIVE

To examine the role of first-trimester uterine artery Doppler, serum β-hCG and pregnancy-associated placental protein-A (PAPP-A) in prediction of preeclampsia and IUGR.

METHODS

A total of 100 pregnant women in the 11-14 weeks' gestation were examined using uterine artery Doppler, serum β-hCG and PAPP-A. All women were followed-up for development of preeclampsia or IUGR.

RESULTS

A total of 94 women completed the study of which 7 (7.4%) developed complications. Uterine artery PI and RI were significantly higher whereas serum β-hCG and PAPP-A levels were significantly reduced in patients who developed complications when compared with those who did not. Uterine artery PI had the highest sensitivity (100%) but a low specificity (56% and 45%) in prediction of preeclampsia and IUGR, respectively. Adding PAPP-A to uterine artery PI elevated the specificity into 94.44% and 95.51%, respectively. Combined PI and β-hCG elevated the specificity into 88.89% and 89.89%, respectively.

CONCLUSION

Our study suggests that first-trimester uterine artery impedance, as measured by Doppler ultrasound as well as low serum biomarkers (β-hCG and PAPP-A) can be used for prediction of preeclampsia and IUGR. The most sensitive is uterine artery PI. Adding β-hCG to PI improves specificity in prediction of both preeclampsia and IUGR. Uterine artery PI plus PAPP-A is the best combination for prediction of both preeclampsia and IUGR.

Shining light in dark corners: diagnosis and management of late-onset fetal growth restriction

Fetal growth restriction (FGR) is the single biggest risk factor for stillbirth. In the absence of any effective treatment for fetal growth restriction, the mainstay of management is close surveillance and timely delivery. While such statements are almost self-evident, the daily clinical challenge of late-onset fetal growth restriction remains; the competing priorities of minimising stillbirth risk, while avoiding excessive obstetric intervention and the neonatal sequelae of iatrogenic preterm birth. This dilemma is made harder because the tools for late-onset FGR diagnosis and surveillance compare poorly to those used in early-onset FGR; screening tests in early pregnancy have limited predictive value; most cases escape clinical detection, a phenomenon set to worsen given the obesity epidemic; there is a failure of consensus on the definition of small for gestational age, and ancillary tools, such as umbilical artery Doppler--of value in identification of preterm FGR--are less useful in the late-preterm period and at term. Most importantly, the problem is common; 96% of all births occur after 32 weeks. This means a poor noise/signal ratio of any test or management algorithm will inevitably have large clinical consequences. Into such a dark corner, we cast some light; a summary on diagnostic criteria, new developments to improve the diagnosis of late-onset FGR and a suggested approach to management.

Maternal Serum Screening Markers and Adverse Outcome: A New Perspective

There have been a number of studies evaluating the association of aneuploidy serum markers with adverse pregnancy outcome. More recently, the development of potential treatments for these adverse outcomes as well as the introduction of cell-free fetal DNA (cffDNA) screening for aneuploidy necessitates a re-evaluation of the benefit of serum markers in the identification of adverse outcomes. Analysis of the literature indicates that the serum markers tend to perform better in identifying pregnancies at risk for the more severe but less frequent form of individual pregnancy complications rather than the more frequent but milder forms of the condition. As a result, studies which evaluate the association of biomarkers with a broad definition of a given condition may underestimate the ability of such markers to identify pregnancies that are destined to develop the more severe form of the condition. Consideration of general population screening using cffDNA solely must be weighed against the fact that traditional screening using serum markers enables detection of severe pregnancy complications, not detectable with cffDNA, of which many may be amenable to treatment options.