Pre-eclampsia screening in Denmark (PRESIDE): national validation study

Reference Intervals for Placental Biomarkers in Early Pregnancy

BACKGROUND

Placental dysfunction is important to recognize, and more evidence is needed on the dynamics of the placental biomarkers, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), in early pregnancy. This study aimed to establish reference intervals for placental biomarkers in early pregnancy.

METHODS

This was a retrospective cohort study of pregnant women (n = 702) in the North Denmark Region, 2013, who had blood samples drawn in early pregnancy including measurements of sFlt-1 and PlGF (Kryptor Compact, Thermofisher Scientific). Reference intervals were established, and the association between sFlt-1 and PlGF and maternal characteristics (age, body mass index [BMI], country of birth, and smoking in pregnancy) was evaluated using linear regression analyses and reported as adjusted beta coefficient (aβ) with 95% confidence intervals (CIs).

RESULTS

The placental biomarkers showed a dynamic trend with higher levels for increasing week of pregnancy; however, sFlt-1 reached a plateau around week 10 of pregnancy. Higher maternal age associated with higher sFlt-1 and PlGF (sFlt-1: aβ 1.02 [95% CI, 1.01-1.03], PlGF: aβ 1.02 [95% CI, 1.01-1.03]), and higher maternal BMI associated with lower sFlt-1 (aβ 0.97 [95% CI, 0.96-0.98]). Furthermore, the level of PlGF was higher among women born outside of Denmark (aβ 1.17 [95% CI, 1.03-1.34]) compared to women born in Denmark and among smokers (aβ 1.56 [95% CI, 1.38-1.78]) compared to nonsmokers.

CONCLUSIONS

In a large cohort of pregnant women in Denmark, levels of sFlt-1 and PlGF increased during early pregnancy and were influenced by a series of maternal characteristics.

Screening for pre-eclampsia using pregnancy-associated plasma protein-A or placental growth factor measurements in blood samples collected at 8-14 weeks' gestation

OBJECTIVES

To assess the value of pregnancy-associated plasma protein-A (PAPP-A) in screening for preterm pre-eclampsia (PE) (delivery < 37 weeks' gestation) measured in maternal blood samples collected before 11 weeks, and to compare the screening performance of PAPP-A with that of placental growth factor (PlGF) from blood samples collected at 8-14 weeks.

METHODS

This study analyzed data from women who participated in the PRESIDE (Pre-eclampsia Screening in Denmark) study, a prospective, non-interventional multicenter study investigating the predictive performance of the Fetal Medicine Foundation first-trimester screening algorithm for PE in a Danish population. As part of combined first-trimester screening, a routine blood sample was collected at 8-14 weeks' gestation and PAPP-A was measured. Excess serum was stored at -80°C and analyzed for PlGF in batches after delivery. Most women in the PRESIDE study had an extra blood sample collected at the time of the first-trimester scan at 11-14 weeks, which was also analyzed for PlGF and PAPP-A in batches after all the participants had delivered. Screening performance was assessed in terms of the detection rate at a 10% screen-positive rate (SPR) for a combination of PAPP-A or PlGF with maternal factors alone and for a combination of each of these biomarkers with maternal factors, mean arterial pressure (MAP) and uterine artery pulsatility index (UtA-PI).

RESULTS

The study population comprised 8386 women who had a routine combined first-trimester aneuploidy screening blood sample collected at 8-14 weeks' gestation. In pregnancies that developed preterm PE, the median PAPP-A multiples of the median from routine blood samples were 0.78 (95% CI, 0.67-0.90) before 10 weeks, 0.80 (95% CI, 0.58-1.10) at 10 weeks and 0.64 (95% CI, 0.53-0.78) at 11-14 weeks. In women with samples collected before 10 weeks, there was no significant improvement in the detection rate of preterm PE when PAPP-A or PlGF was combined with maternal factors alone or when combined with maternal factors, MAP and UtA-PI. In routine samples collected at or after 10 weeks, PAPP-A only increased the detection rate of preterm PE slightly. However, PlGF in samples collected at or after 10 weeks increased the detection rate from 31.3% (95% CI, 16.1-50.0%) to 56.3% (95% CI, 37.7-73.6%) at a 10% SPR, i.e. an increase in the detection rate of 25.0% (95% CI, 4.3-44.4%), when combined with maternal factors alone. When PlGF collected from the PRESIDE sample at 11-14 weeks was combined with maternal factors, MAP and UtA-PI, there was an increase in the detection rate from 50.9% (95% CI, 37.1-64.6%) to 67.3% (95% CI, 53.3-79.3%), i.e. an increase of 16.4% (95% CI, 5.6-29.0%) at a 10% SPR.

CONCLUSIONS

PAPP-A has limited value in first-trimester screening for PE, whereas PlGF adds significantly to the detection rate of preterm PE at 10-14 weeks' gestation. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Adverse Obstetric Outcomes in Pregnancies With Major Fetal Congenital Heart Defects

Importance

Understanding the risk profile of obstetric complications in pregnancies with fetal major congenital heart defects (MCHDs) is crucial for obstetric counseling and care.

Objective

To investigate the risk of placenta-related adverse obstetric outcomes in pregnancies complicated by fetal MCHDs.

Design, Setting, and Participants

This cohort study retrieved data from June 1, 2008, to June 1, 2018, from the Danish Fetal Medicine Database, which includes comprehensive data on more than 95% of all pregnancies in Denmark since the database was instituted in 2008. All singleton pregnancies that resulted in a live-born child after 24 weeks' gestation without chromosomal aberrations were included. A systematic search of the literature was performed in PubMed, Embase, and the Cochrane Library from inception to June 1, 2024, to compile existing knowledge and data on adverse obstetric outcomes among MCHD subtypes.

Exposure

Fetal MCHDs including 1 of 11 subtypes.

Main Outcomes and Measures

The primary outcome was a composite adverse obstetric outcome defined as preeclampsia, preterm birth, fetal growth restriction, or placental abruption. Secondary outcomes consisted of each adverse obstetric event. Adjusted odds ratios (AORs) were computed using generalized estimating equations adjusted for maternal body mass index, age, smoking, and year of delivery. Meta-analyses were conducted using random-effects models to pool effect sizes for each MCHD subtype and adverse obstetric outcome.

Results

A total of 534 170 pregnancies were included in the Danish cohort, including 745 with isolated fetal MCHDs (median [IQR] maternal age, 29.0 [26.0-33.0] years) and 533 425 without MCHDs (median [IQR] maternal age, 30.0 [26.0-33.0] years). Pregnancies with fetal MCHDs exhibited a higher rate of adverse obstetric outcomes at 22.8% compared with 9.0% in pregnancies without fetal MCHDs (AOR, 2.96; 95% CI, 2.49-3.53). Preeclampsia (AOR, 1.83; 95% CI, 1.33-2.51), preterm birth at less than 37 weeks (AOR, 3.84; 95% CI, 3.15-4.71), and fetal growth restriction (AOR, 3.25; 95% CI, 2.42-4.38) occurred significantly more frequently in pregnancies with MCHDs. Except for fetal transposition of the great arteries (AOR, 1.19; 95% CI, 0.66-2.15), all MCHD subtypes carried a greater risk of adverse obstetric outcomes. The meta-analysis included 10 additional studies that supported these results.

Conclusions and Relevance

These findings suggest that nearly 1 in 4 women expecting a child with an MCHD, except transposition of the great arteries, may be at high risk of adverse obstetric outcomes.

Preterm birth in assisted reproduction: the mediating role of hypertensive disorders in pregnancy

STUDY QUESTION

To what extent can hypertensive disorders in pregnancy (HDP) explain the higher risk of preterm birth following frozen embryo transfer (frozen-ET) and fresh embryo transfer (fresh-ET) in ART compared with naturally conceived pregnancies?

SUMMARY ANSWER

HDP did not contribute to the higher risk of preterm birth in pregnancies after fresh-ET but mediated 20.7% of the association between frozen-ET and preterm birth.

WHAT IS KNOWN ALREADY

Risk of preterm birth is higher after ART compared to natural conception. However, there is also a higher risk of HDP in pregnancies after ART compared to natural conception, in particular after frozen-ET. HDP increases the risk of both spontaneous and medically indicated preterm birth. It is not known to what extent the higher risk of preterm birth in ART-conceived pregnancies is mediated through HDP.

STUDY DESIGN, SIZE, DURATION

This registry-based cohort study included singleton pregnancies from the Committee of Nordic ART and Safety (CoNARTaS) cohort from Denmark (1994-2014), Norway (1988-2015), and Sweden (1988-2015). The analysis included 78 300 singletons born after fresh-ET, 18 037 after frozen-ET, and 4 426 682 after natural conception. The exposure was ART conception with either frozen-ET or fresh-ET versus natural conception. The main mediator of interest was any of the following HDP: gestational hypertension, preeclampsia, eclampsia, or chronic hypertension with superimposed preeclampsia. The main outcome was any preterm birth, defined as delivery <37 weeks of gestation. Secondary outcomes were spontaneous and medically indicated preterm birth, and different severities of preterm birth based on the gestational age threshold.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We linked data from the national Medical Birth Registries, ART registries/databases, and the National Patient Registries in each country using the unique national identity number of the mother. Criteria for inclusion were singleton pregnancies with birth order 1-4 in women aged ≥20 years at delivery. We used logistic regression to estimate odds ratios (ORs) with 95% CIs of preterm birth and decomposed the total effect into direct and mediated (indirect) effects to estimate the proportion mediated by HDP. Main models included adjustment for the year of delivery, maternal age, parity, and country.

MAIN RESULTS AND THE ROLE OF CHANCE

Pregnancies following frozen-ET had a higher risk of any preterm birth compared to natural conception (occurrence 6.6% vs 5.0%, total effect OR 1.29, 95% CI 1.21-1.37) and 20.7% of the association was mediated by HDP (mediated effect OR 1.05, 95% CI 1.04-1.05). The mediation occurred primarily in medically indicated preterm births. Pregnancies following fresh-ET also had a higher risk of any preterm birth compared to naturally conceived pregnancies (occurrence 8.1% vs 5.0%, total effect OR 1.49, 95% CI: 1.45-1.53), but none of this could be mediated by HDP (mediated effect OR 1.00, 95%CI 1.00-1.00, proportion mediated 0.5%). Sensitivity analyses with extra confounder adjustment for body mass index and smoking, and restriction to primiparous women, were consistent with our main findings. Furthermore, the results were not driven by differences in ART procedures (intracytoplasmic sperm injection, culture duration, or the number of embryos transferred).

LIMITATIONS, REASONS FOR CAUTION

Although we could adjust for some important confounders, we cannot exclude residual confounding, particularly from factors associated with infertility.

WIDER IMPLICATIONS OF THE FINDINGS

This population-based mediation analysis suggests that some of the higher risk of preterm birth after ART treatment may be explained by the higher risk of HDP after frozen-ET. If causality is established, investigations into preventive strategies such as prophylactic aspirin in pregnancies after frozen-ET may be warranted.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was provided by NordForsk (project number: 71450), the Nordic Federation of Obstetrics and Gynaecology (project numbers NF13041, NF15058, NF16026, and NF17043), the Norwegian University of Science and Technology (project number 81850092), an ESHRE Grant for research in reproductive medicine (grant number 2022-2), and the Research Council of Norway's Centres of Excellence funding scheme (project number 262700). D.A.L.'s and A.E.'s contribution to this work was supported by the European Research Council under the European Union's Horizon 2020 research and innovation program (grant agreements No 101021566) and the UK Medical Research Council (MC_UU_00032/05). D.A.L. has received support from Roche Diagnostics and Medtronic Ltd for research unrelated to that presented here. Pinborg declares grants from Gedeon Richter, Ferring, Cryos, and Merck, consulting fees from IBSA, Ferring, Gedeon Richter, Cryos, and Merck, payments from Gedeon Richter, Ferring, Merck, and Organon,travel support from Gedeon Richter. All other authors declare no conflicts of interest related to this work.

TRIAL REGISTRATION NUMBER

ISRCTN 35879.

Advancing diagnosis and early risk assessment of preeclampsia through noninvasive cell-free DNA methylation profiling

BACKGROUND

Aberrant embryo implantation and suboptimal placentation can lead to (severe) complications such as preeclampsia and fetal growth restriction later in pregnancy. Current identification of high-risk pregnancies relies on a combination of risk factors, biomarkers, and ultrasound examinations, a relatively inaccurate approach. Previously, aberrant DNA methylation due to placental hypoxia has been identified as a potential marker of placental insufficiency and, hence, potential (future) pregnancy complications. The goal of the Early Prediction of prEgnancy Complications Testing, or the ExPECT study, is to validate a genome-wide, cell-free DNA (cfDNA) methylation strategy to diagnose preeclampsia accurately. More importantly, the predictive potential of this strategy is also explored to reliably identify high-risk pregnancies early in gestation. Furthermore, a longitudinal study was conducted, including sequential blood samples from pregnant individuals experiencing both uneventful and complicated gestations, to assess the methylation dynamics of cfDNA throughout these pregnancies. A significant strength of this study is its enzymatic digest, which enriches CpG-rich regions across the genome without the need for proprietary reagents or prior selection of regions of interest. This makes it useful for the cost-effective discovery of novel markers.

RESULTS

Investigation of methylation patterns throughout pregnancy showed different methylation trends between unaffected and affected pregnancies. We detected differentially methylated regions (DMRs) in pregnancies complicated with preeclampsia as early as 12 weeks of gestation, with distinct differences in the methylation profile between early and late pregnancy. Two classification models were developed to diagnose and predict preeclampsia, demonstrating promising results on a small set of validation samples.

CONCLUSIONS

This study offers valuable insights into methylation changes at specific genomic regions throughout pregnancy, revealing critical differences between normal and complicated pregnancies. The power of noninvasive cfDNA methylation profiling was successfully proven, suggesting the potential to integrate this noninvasive approach into routine prenatal care.

Prospective Validation of First-Trimester Screening for Preterm Preeclampsia in Nulliparous Women (PREDICTION Study)

BACKGROUND

Fetal Medicine Foundation (FMF) studies suggest that preterm preeclampsia can be predicted in the first trimester by combining biophysical, biochemical, and ultrasound markers and prevented using aspirin. We aimed to evaluate the FMF preterm preeclampsia screening test in nulliparous women.

METHODS

We conducted a prospective multicenter cohort study of nulliparous women recruited at 11 to 14 weeks. Maternal characteristics, mean arterial blood pressure, PAPP-A (pregnancy-associated plasma protein A), PlGF (placental growth factor) in maternal blood, and uterine artery pulsatility index were collected at recruitment. The risk of preterm preeclampsia was calculated by a third party blinded to pregnancy outcomes. Receiver operating characteristic curves were used to estimate the detection rate (sensitivity) and the false-positive rate (1-specificity) for preterm (<37 weeks) and for early-onset (<34 weeks) preeclampsia according to the FMF screening test and according to the American College of Obstetricians and Gynecologists criteria.

RESULTS

We recruited 7554 participants including 7325 (97%) who remained eligible after 20 weeks of which 65 (0.9%) developed preterm preeclampsia, and 22 (0.3%) developed early-onset preeclampsia. Using the FMF algorithm (cutoff of ≥1 in 110 for preterm preeclampsia), the detection rate was 63.1% for preterm preeclampsia and 77.3% for early-onset preeclampsia at a false-positive rate of 15.8%. Using the American College of Obstetricians and Gynecologists criteria, the equivalent detection rates would have been 61.5% and 59.1%, respectively, for a false-positive rate of 34.3%.

CONCLUSIONS

The first-trimester FMF preeclampsia screening test predicts two-thirds of preterm preeclampsia and three-quarters of early-onset preeclampsia in nulliparous women, with a false-positive rate of ≈16%.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02189148.

Externally validated prediction models for pre-eclampsia: systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the performance of existing externally validated prediction models for pre-eclampsia (PE) (specifically, any-onset, early-onset, late-onset and preterm PE).

METHODS

A systematic search was conducted in five databases (MEDLINE, EMBASE, Emcare, CINAHL and Maternity & Infant Care Database) and using Google Scholar/reference search to identify studies based on the Population, Index prediction model, Comparator, Outcome, Timing and Setting (PICOTS) approach until 20 May 2023. We extracted data using the CHARMS checklist and appraised the risk of bias using the PROBAST tool. A meta-analysis of discrimination and calibration performance was conducted when appropriate.

RESULTS

Twenty-three studies reported 52 externally validated prediction models for PE (one preterm, 20 any-onset, 17 early-onset and 14 late-onset PE models). No model had the same set of predictors. Fifteen any-onset PE models were validated externally once, two were validated twice and three were validated three times, while the Fetal Medicine Foundation (FMF) competing-risks model for preterm PE prediction was validated widely in 16 different settings. The most common predictors were maternal characteristics (prepregnancy body mass index, prior PE, family history of PE, chronic medical conditions and ethnicity) and biomarkers (uterine artery pulsatility index and pregnancy-associated plasma protein-A). The FMF model for preterm PE (triple test plus maternal factors) had the best performance, with a pooled area under the receiver-operating-characteristics curve (AUC) of 0.90 (95% prediction interval (PI), 0.76-0.96), and was well calibrated. The other models generally had poor-to-good discrimination performance (median AUC, 0.66 (range, 0.53-0.77)) and were overfitted on external validation. Apart from the FMF model, only two models that were validated multiple times for any-onset PE prediction, which were based on maternal characteristics only, produced reasonable pooled AUCs of 0.71 (95% PI, 0.66-0.76) and 0.73 (95% PI, 0.55-0.86).

CONCLUSIONS

Existing externally validated prediction models for any-, early- and late-onset PE have limited discrimination and calibration performance, and include inconsistent input variables. The triple-test FMF model had outstanding discrimination performance in predicting preterm PE in numerous settings, but the inclusion of specialized biomarkers may limit feasibility and implementation outside of high-resource settings. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Performance of machine-learning approach for prediction of pre-eclampsia in a middle-income country

OBJECTIVE

Pre-eclampsia (PE) is a serious complication of pregnancy associated with maternal and fetal morbidity and mortality. As current prediction models have limitations and may not be applicable in resource-limited settings, we aimed to develop a machine-learning (ML) algorithm that offers a potential solution for developing accurate and efficient first-trimester prediction of PE.

METHODS

We conducted a prospective cohort study in Mexico City, Mexico to develop a first-trimester prediction model for preterm PE (pPE) using ML. Maternal characteristics and locally derived multiples of the median (MoM) values for mean arterial pressure, uterine artery pulsatility index and serum placental growth factor were used for variable selection. The dataset was split into training, validation and test sets. An elastic-net method was employed for predictor selection, and model performance was evaluated using area under the receiver-operating-characteristics curve (AUC) and detection rates (DR) at 10% false-positive rates (FPR).

RESULTS

The final analysis included 3050 pregnant women, of whom 124 (4.07%) developed PE. The ML model showed good performance, with AUCs of 0.897, 0.963 and 0.778 for pPE, early-onset PE (ePE) and any type of PE (all-PE), respectively. The DRs at 10% FPR were 76.5%, 88.2% and 50.1% for pPE, ePE and all-PE, respectively.

CONCLUSIONS

Our ML model demonstrated high accuracy in predicting pPE and ePE using first-trimester maternal characteristics and locally derived MoM. The model may provide an efficient and accessible tool for early prediction of PE, facilitating timely intervention and improved maternal and fetal outcome. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Screening for pre-eclampsia with competing-risks model using placental growth factor measurement in blood samples collected before 11 weeks' gestation

OBJECTIVES

To describe the distributional properties and assess the performance of placental growth factor (PlGF) measured in blood samples collected before 11 weeks' gestation in the prediction of pre-eclampsia (PE).

METHODS

The study population consisted of pregnant women included in the Pre-eclampsia Screening in Denmark (PRESIDE) study with a PlGF measurement from the routine combined first-trimester screening (cFTS) blood sample collected at 8-14 weeks' gestation. PRESIDE was a prospective multicenter study investigating the predictive performance of the Fetal Medicine Foundation (FMF) first-trimester screening algorithm for PE in a Danish population. In the current study, serum concentration of PlGF in the cFTS blood samples was analyzed in batches between January and June 2021.

RESULTS

A total of 8386 pregnant women were included. The incidence of PE was 0.7% at < 37 weeks' gestation and 3.0% at ≥ 37 weeks. In blood samples collected at 10 weeks' gestation, PlGF multiples of the median (MoM) were significantly lower in pregnancies with preterm PE < 37 weeks compared to unaffected pregnancies. However, PlGF MoM did not differ significantly between pregnancies with PE and unaffected pregnancies in samples collected before 10 weeks' gestation.

CONCLUSIONS

The gestational-age range for PlGF sampling may be expanded from 11-14 to 10-14 weeks when assessing the risk for PE using the FMF first-trimester screening model. There is little evidence to support the use of PlGF in blood samples collected before 10 weeks' gestation. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

First-trimester prediction of preterm pre-eclampsia and prophylaxis by aspirin: Effect on spontaneous and iatrogenic preterm birth

OBJECTIVE

To report the predictive performance for preterm birth (PTB) of the Fetal Medicine Foundation (FMF) triple test and National Institute for health and Care Excellence (NICE) guidelines used to screen for pre-eclampsia and examine the impact of aspirin in the prevention of PTB.

DESIGN

Secondary analysis of data from the SPREE study and the ASPRE trial.

SETTING

Multicentre studies.

POPULATION

In SPREE, women with singleton pregnancies had screening for preterm pre-eclampsia at 11-13 weeks of gestation by the FMF method and NICE guidelines. There were 16 451 pregnancies that resulted in delivery at ≥24 weeks of gestation and these data were used to derive the predictive performance for PTB of the two methods of screening. The results from the ASPRE trial were used to examine the effect of aspirin in the prevention of PTB in the population from SPREE.

METHODS

Comparison of performance of FMF method and NICE guidelines for pre-eclampsia in the prediction of PTB and use of aspirin in prevention of PTB.

MAIN OUTCOME MEASURE

Spontaneous PTB (sPTB), iatrogenic PTB for pre-eclampsia (iPTB-PE) and iatrogenic PTB for reasons other than pre-eclampsia (iPTB-noPE).

RESULTS

Estimated incidence rates of sPTB, iPTB-PE and iPTB-noPE were 3.4%, 0.8% and 1.6%, respectively. The corresponding detection rates were 17%, 82% and 25% for the triple test and 12%, 39% and 19% for NICE guidelines, using the same overall screen positive rate of 10.2%. The estimated proportions prevented by aspirin were 14%, 65% and 0%, respectively.

CONCLUSION

Prediction of sPTB and iPTB-noPE by the triple test was poor and poorer by the NICE guidelines. Neither sPTB nor iPTB-noPE was reduced substantially by aspirin.

Screening for pre-eclampsia by maternal serum glycosylated fibronectin at 11-13 weeks' gestation

OBJECTIVE

To examine the performance of screening for preterm and term pre-eclampsia (PE) at 11-13 weeks' gestation by maternal factors and combinations of maternal serum glycosylated fibronectin (GlyFn), mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI) and serum placental growth factor (PlGF).

METHODS

This was a case-control study in which maternal serum GlyFn was measured using a point-of-care device in stored samples from a non-intervention screening study of singleton pregnancies at 11 + 0 to 13 + 6 weeks' gestation. In the same samples, PlGF was measured by time-resolved fluorometry. We used samples from women who delivered with PE at < 37 weeks' gestation (n = 100), PE at ≥ 37 weeks (n = 100), gestational hypertension (GH) at < 37 weeks (n = 100), GH at ≥ 37 weeks (n = 100) and 1000 normotensive controls with no pregnancy complications. In all cases, MAP and UtA-PI had been measured during the routine 11-13-week visit. Levels of GlyFn were transformed to multiples of the expected median (MoM) values after adjusting for maternal demographic characteristics and elements of medical history. Similarly, the measured values of MAP, UtA-PI and PlGF were converted to MoMs. The competing-risks model was used to combine the prior distribution of gestational age at delivery with PE, obtained from maternal characteristics, with various combinations of biomarker MoM values to derive the patient-specific risks of delivery with PE or GH at < 37 and ≥ 37 weeks' gestation. Screening performance was estimated by examining the area under the receiver-operating-characteristics curve (AUC) and detection rate (DR) at 10% fixed false-positive rate (FPR).

RESULTS

The maternal characteristics and elements of medical history with a significant effect on the measurement of GlyFn were maternal age, weight, height, race, smoking status and history of PE. In pregnancies that developed PE, GlyFn MoM was increased and the deviation from normal decreased with increasing gestational age at delivery. The DR and AUC of screening for delivery with PE at < 37 weeks' gestation by maternal factors alone were 50% and 0.834, respectively, and these increased to 80% and 0.949, respectively, when maternal risk factors were combined with MAP, UtA-PI and PlGF (triple test). The performance of the triple test was similar to that of screening by a combination of maternal factors, MAP, UtA-PI and GlyFn (DR, 79%; AUC, 0.946) and that of screening by a combination of maternal factors, MAP, PlGF and GlyFn (DR, 81%; AUC, 0.932). The performance of screening for delivery with PE at ≥ 37 weeks' gestation was poor; the DR for screening by maternal factors alone was 35% and increased to only 39% with use of the triple test. Similar results were obtained when GlyFn replaced PlGF or UtA-PI in the triple test. The DR of screening for GH with delivery at < 37 and ≥ 37 weeks' gestation by maternal factors alone was 34% and 25%, respectively, and increased to 54% and 31%, respectively, with use of the triple test. Similar results were obtained when GlyFn replaced PlGF or UtA-PI in the triple test.

CONCLUSIONS

GlyFn is a potentially useful biomarker in first-trimester screening for preterm PE, but the findings of this case-control study need to be validated by prospective screening studies. The performance of screening for term PE or GH at 11 + 0 to 13 + 6 weeks' gestation by any combination of biomarkers is poor. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.