First-trimester Combined Test Research Articles

Eliminating first trimester combined testing: Consequences for early detection of significant fetal anomalies.

To determine whether implementation of cell-free DNA (cfDNA) testing for aneuploidy as a first-tier test and subsequent abolition of first trimester combined testing (FCT) affected the first trimester detection (<14weeks) of certain fetal anomalies. We performed a geographical cohort study in two Fetal Medicine Units between 2011 and 2020, including 705 fetuses with prenatally detected severe brain, abdominal wall and congenital heart defects. Cases were divided into two groups: before (n=396) and after (n=309) cfDNA introduction. The primary outcome was the first trimester detection rate (<14weeks) overall and for non-chromosomal anomalies solely. Overall, gastroschisis, AVSD and HLHS were detected more often in the first trimester in the before group compared to the after group, respectively 54.5% versus 18.5% (p=0.004), 45.9% versus 26.9% (p=0.008) and 30% versus 3.4% (p=0.005). After exclusion of chromosomal anomalies identifiable through cfDNA testing, the detection of AVSD remained higher in the before group (43.3% vs. 9.5%, p=0.02), leading to a possible earlier gestation at termination. The termination of pregnancy (TOP) rate did not differ among the groups. In the after group, referrals for suspected anomalies following a dating scan between 11 and 14weeks significantly increased from 17.4% to 29.1% (p<0.001). This study underscores the value of a scan dedicated to fetal anatomy in the first trimester as we observed a decline in the early detection of certain fetal anomalies (detectable in the first trimester) subsequent to the abolition of FCT.

Non-invasive prenatal testing for everybody or contingent screening?

To compare the advantages and disadvantages of two main implementation strategies for non-invasive prenatal testing (NIPT) for the detection of trisomies 21, 13 and 18 in public healthcare settings. These concern NIPT as a first-tier screening test for all pregnant women, or NIPT contingent on an increased risk first-trimester combined test (FCT) result. Comparison based on (un)published data and literature. Despite the lower prevalence of trisomies in the low-risk population, data show that the positive predictive value (PPV) and detection-miscarriage ratio of first-tier NIPT are comparable to NIPT used as contingency test. Advantages of NIPT as a first-tier test compared to FCT with contingent NIPT are that there is no time-window for testing, sensitivity is higher, fewer women need follow-up testing (PPV of NIPT is higher than PPV of FCT), less anxiety for pregnant women and partners. When given the choice, pregnant women prefer first-tier NIPT. Although contingency testing still seems to be the cheaper option, the differences in costs are becoming increasingly smaller and might soon disappear. We argue that NIPT should preferably be offered as a first-tier test for the detection of fetal aneuploidies for all pregnant women, provided that women are supported to make informed decisions. This article is protected by copyright. All rights reserved.

First-Trimester Biochemical Serum Markers in Female Kidney Transplant Recipients-The Impact of Graft Function.

Data on serum biochemistry markers as a component of the first-trimester screening test in pregnant kidney graft recipients are limited. In the absence of a separate validated algorithm, biochemical testing is commonly used in the first-trimester screening in kidney transplant recipients. Therefore, the study aimed to analyze first-trimester serum biochemical markers and the first trimester combined screening results in pregnant kidney graft recipients. A retrospective study was carried out in pregnant women who underwent the first-trimester combined screening test performed per the Fetal Medicine Foundation (FMF) protocol in 2009−2020. The study group included 27 pregnancies in kidney graft transplant recipients, and the control group was 110 patients with normal kidney function, matched according to age, body mass index (BMI), and gestational age. The biochemical serum markers (free beta-human chorionic gonadotropin [beta-hCG] and pregnancy-associated plasma protein A [PAPP-A]) were evaluated using the FMF-approved Roche Elecsys® assay and exhibited as multiples of the median (MoM) values. Data on first-trimester screening test results, perinatal outcomes, and graft function (assessed using serum creatinine concentrations) were analyzed. The analysis of first-trimester screening parameters revealed no difference in nuchal translucency (NT) measurements and uterine artery flow. However, free beta-hCG MoM and PAPP-A values were higher in posttransplant pregnancies than in controls: 3.47 ± 2.08 vs. 1.38 ± 0.85 (p = 0.035) and 1.46 ± 0.81 vs. 0.98 ± 0.57 (p = 0.007), respectively. The false positive rate of trisomy 21 (T21) screening in graft recipients was 25.9% vs. 3% in the controls. The free β-hCG MoM values positively correlated with serum creatinine levels before (r = 0.653; p < 0.001), during (r = 0.619; p = 0.001), and after pregnancy (r = 0.697; p < 0.001). There was a statistically significant negative correlation for PAPP-A MoM values for postpartum serum creatinine concentration (r = −0.424, p = 0.035). Our results show significantly higher serum concentrations of free beta-hCG and PAPP-A in posttransplant pregnancies than in healthy controls, confirmed when exhibited as MoM values and their association with graft function was assessed by serum creatinine concentration. Taking those changes into account would reduce the high number of false positive test results in this group. The validated first-trimester screening algorithm that considers altered kidney function in pregnant kidney graft recipients remains to be developed.

Does a High-Risk (>1/50) Result for First-Trimester Combined Screening Always Entail Invasive Testing? Which Patients from This Group Might Benefit from cfDNA Testing?

Currently, cell-free DNA (cfDNA) is offered as part of a contingent screening for patients with a first-trimester combined test (FCT) risk between 1/50 and 1/250. However, most aneuploidies are within the group of patients with a risk above 1/10. An observational, retrospective, and multi-centric study was carried out, to evaluate the theorical performance of lowering the cut-off point for the high-risk group from 1/50 to 1/10. Out of the 25,920 patients included, 25,374 (97.9%) consented to the cfDNA contingent screening for aneuploidies. With the proposed strategy, knowing that the detection rate (DR) of cfDNA testing for trisomy 21 is 99.7%, the DR for trisomy 21 would have stayed in a 93.2%, just as it was with the current strategy. In this instance, 267 (1.1%) invasive tests would have been performed, while the current strategy had a total of 307 (1.2%). The false positive rate (FPR) rate would have stayed at 5.2% in both scenarios. In conclusion, the contingent screening of aneuploidies based in the result of the FCT, offering the analysis of cfDNA to patients with an intermediate risk after lowering the cut-off point from 1/50 to 1/10, is a valid alternative that might maintain the current detection rates and avoid the complications associated with invasive testing.

Contingent cfDNA Screening Implementation: Increasing Diagnostic Accuracy and Reducing Invasive Testing – 6 Years’ Results in a Single Center

Objectives: Universal screening for trisomy using cell-free DNA (cfDNA) has proven to be more effective than combined test, but it is not cost efficient currently. Contingent cfDNA screening on the results of the first-trimester combined test can improve the detection rate of the combined test and reduce the number of invasive tests at a lower cost than universal screening. In 2018, a contingent screening program was implemented in the community of Castilla y Leon (Spain). This study aims to compare the results achieved in Salamanca University Hospital during the first 3 years of contingent screening (2018–2020) with those of the previous 3 years (2015–2017) to assess the changes in the trisomy detection rate and the number of invasive tests. Methods: A total of 9,903 singleton pregnancies without malformations nor nuchal translucency >p99 were included. 5,165 patients underwent combined screening and 4,738 had contingent screening based on the combined test risk. In the combined test group, women were offered an invasive test if the risk was ≥1:270, while risks under 1:270 were considered low risks, and no further testing was offered. In the contingent screening group, invasive testing was offered if the risk was ≥1:100 (≥1:50 from 2020 onwards), while cfDNA was offered if the combined test risk was between 1:100 and 1:1,000 (1:50–1:1,000 from 2020 onwards). When risk was <1:1,000, no further testing was offered. Aneuploidies detected by cfDNA were confirmed by invasive diagnostic testing. Results: There were 33 cases of trisomy 21 (T21) throughout the 6 years of study. Four cases had low/intermediate risks and were spotted by cfDNA. Risk >1:1,000 threshold for contingent test detected 100% T21. There was a false-positive result for trisomy 13. There were no false-negative results. “No-call” cfDNA results were minimized by repeating blood collection 2 weeks later, as fetal fraction (FF) was doubled. Invasive testing had a drop rate of 84% after contingent screening implementation. Discussion: The implementation of population-based contingent screening significantly reduces the number of invasive tests without lowering diagnostic accuracy. To achieve the maximum efficiency of the program, it is important to know the best cut-offs according to the population where the program is to be implemented. The number of uninformative results due to low FF can be reduced by repeating the test 2 weeks after the initial extraction: this increases the FF to twice the initial one, achieving informative results and avoiding unnecessary invasive tests.

Is cell-free fetal DNA testing a safe option for women in a high-risk population after combined first-trimester testing?

ObjectivesOur study aimed to examine the relevance of cell-free fetal DNA (cfDNA) testing on the screening of chromosomal defects and the issue of pregnancies in patients with a risk over 1:50 after the first-trimester combined test. MethodsThis is a retrospective monocentric study. We included all consecutive patients with a singleton pregnancy between January 2015 and December 2020 attending our fetal medicine center because the estimated risk for trisomy 21 after the first-trimester combined screening was over 1:50. The patients could either choose to have invasive testing or cell-free DNA testing. We collected data about the patient, the tests results (cfDNA, karyotype) and the pregnancy outcome (born alive, medical termination, miscarriage or intrauterine fetal death). ResultsWe included 98 patients with an estimated risk for trisomy 21 over 1:50. We found a total of 14 major chromosomal abnormalities (14/98; 14.3%), of which: thirteen trisomies 21 and one triploidy 69, XXY. A cfDNA testing was chosen by 34 (34/98; 34.7%) patients. Among the pathological results of invasive testing, 5 (5/64; 7.8%) couldn't be targeted by cfDNA testing. Two of them were placental mosaicism, one a triploidy 69, XXY, and two defects inherited from a parent and considered benign. There was no miscarriage linked to an invasive test in the population study. ConclusionIn our monocentric cohort, a third of the patients choose cfDNA in a case of a risk over 1:50 after combined testing. Even if this cohort is too small to draw definitive conclusions, cfDNA could be safe in a high-risk population after combined testing. None of the chromosomal abnormalities found at the karyotype and non-detectable by cfDNA was a loss of information that impacted pregnancy follow-up. Further study could explore the input of Genome-Wide cfDNA and chromosomal micro-array in this population.

Non-invasive prenatal testing (NIPT) and pregnant women's views on good motherhood: a qualitative study.

Women's views on responsible motherhood influence decision-making regarding participation in prenatal screening. Previous studies showed that the probabilistic nature of the first-trimester combined test and the potential requirement for subsequent invasive diagnostics serve as legitimate reasons for women to exclude prenatal screening from their moral responsibilities. These moral barriers might now be less relevant with the introduction of the non-invasive prenatal test (NIPT) resulting in women feeling a moral duty to use NIPT screening as part of responsible motherhood. This qualitative study explores the impact of NIPT on women's moral beliefs about the meaning of prenatal screening in relation to responsible motherhood. We performed semi-structured interviews with 29 pregnant women who were offered NIPT as a first-tier screening test within a Dutch nationwide study (TRIDENT-2). Results show that the inherent uncertainty about the fetus's health despite improved accuracy and the lack of treatment for a detected disorder, combined with the possibility to obtain information about actionable anomalies through the fetal anomaly scan, support women's perspectives that NIPT is not an obligation of responsible motherhood. Acceptance of NIPT is considered to be a free decision related to the information each woman needs to be a good mother for her child and her family. Women's views may change when NIPT has expanded to include treatable or preventable conditions.

Uptake of fetal aneuploidy screening after the introduction of the non-invasive prenatal test: A national population-based register study.

IntroductionThe introduction of the non‐invasive prenatal test (NIPT) has shifted the prenatal screening landscape. Countries are exploring ways to integrate NIPT in their national prenatal screening programs, either as a first‐ or second‐tier test. This study aimed to describe how the uptake of fetal aneuploidy screening changed after the introduction of NIPT as a second‐tier and as a first‐tier test within the national prenatal screening program of the Netherlands.Material and methodsA population‐based register study in the Netherlands, recording uptake of fetal aneuploidy screening. Data from all pregnant women choosing to have the first‐trimester combined test (FCT) or first‐tier NIPT between January 2007 and March 2019 were retrospectively collected using national registration systems. Uptake percentages for fetal aneuploidy screening (FCT and NIPT) were calculated and stratified by region and maternal age. Statistical significance was determined using trend analysis and chi‐squared tests.ResultsBetween 2007 and 2013 FCT uptake increased from 14.8% to 29.5% (P = .004). In April 2014 NIPT was introduced as a second‐tier test for high‐risk women after FCT (TRIDENT‐1 study). FCT uptake rose from 29.5% in 2013 to 34.2% in 2015 (P < .0001). After the introduction of NIPT as a first‐tier test for all women in April 2017 (TRIDENT‐2 study), FCT uptake declined significantly from 35.8% in 2016 to 2.6% in 2018 (P < .0001). NIPT uptake increased to 43.4% in 2018. Regionally, NIPT uptake ranged from 31.8% to 67.9%. Total uptake (FCT and NIPT) between 2007 and 2018 increased significantly from 14.8% to 45.9% (P < .0001). However, total uptake stabilized at 46% for both years of TRIDENT‐2 (April 2017‐March 2019).ConclusionsAn increase in total fetal aneuploidy screening uptake up to 45.9% was observed after the introduction of NIPT. Uptake appears to have stabilized within a year after introducing first‐tier NIPT.

First trimester screening for aneuploidy: may combined test and fetal DNA work together?

Introduction The purpose of the study was to evaluate the screening performance of combined test (based on the measurement of nuchal translucency, pregnancy-associated plasma protein A, free β-human chorionic gonadotropin, and maternal age) and fetal DNA screening (NIPS) for trisomies 21 (T21), 18 (T18), and 13 (T13). Material and methods Women who accepted screening had a first-trimester combined test (pregnancy-associated plasma protein A, free β-human chorionic gonadotropin, nuchal translucency interpreted with maternal age) and fetal DNA. Results Among 302 women screened (including 4 with affected pregnancies), our study demonstrated that DNA screening for trisomies 21, 18, and 13 achieved a detection rate of 100% with a false-positive rate of 0.02%, overcoming the traditional combined test with 75% of sensitivity and 4.7% of false-positive rate. In particular, fetal DNA may be useful in case of intermediate risk, in order to avoid invasive diagnostic procedures such villocentesis and amniocentesis. Because of fetal DNA costs, it can be used in clinical practice as a second step screening in case of intermediate or high risk at combined test. Conclusion Fetal DNA screening may be successfully implemented in routine care, achieving a high detection rate, low false-positive rate, and, consequently, greater safety with fewer invasive diagnostic tests than other methods of screening.

Clinical and Economic Evaluation after Adopting Contingent Cell-Free DNA Screening for Fetal Trisomies in South Spain

Introduction: Contingent cell-free (cf) DNA screening on the basis of the first-trimester combined test (FCT) results has emerged as a cost-effective strategy for screening of trisomy 21 (T21). Objectives: To assess performance, patients’ uptake, and cost of contingent cfDNA screening and to compare them with those of the established FCT. Methods: This is a prospective cohort study including all singleton pregnancies attending to their FCT for screening of T21 at 2 university hospitals in South Spain. When the FCT risk was ≥1:50, there were major fetal malformations, or the nuchal translucency was ≥3.5 mm, women were recommended invasive testing (IT); if the risk was between 1:50 and 1:270, women were recommended cfDNA testing; and for risks bellow 1:270, no further testing was recommended. Detection rate (DR), false-positive rate (FPR), patients’ uptake, and associated costs were evaluated. Results: We analyzed 10,541 women, including 46 T21 cases. DR of our contingent strategy was 89.1% (41/46) at 1.4% (146/10,541) FPR. Uptake of cfDNA testing was 91.2% (340/373), and overall IT rate was 2.0%. The total cost of our strategy was €1,462,895.7, similar to €1,446,525.7 had cfDNA testing not been available. Conclusions: Contingent cfDNA screening shows high DR, low IT rate, and high uptake at a similar cost than traditional screening.

TRIDENT-2: National Implementation of Genome-wide Non-invasive Prenatal Testing as a First-Tier Screening Test in the Netherlands

The Netherlands launched a nationwide implementation study on non-invasive prenatal testing (NIPT) as a first-tier test offered to all pregnant women. This started on April 1, 2017 as the TRIDENT-2 study, licensed by the Dutch Ministry of Health. In the first year, NIPT was performed in 73,239 pregnancies (42% of all pregnancies), 7,239 (4%) chose first-trimester combined testing, and 54% did not participate. The number of trisomies 21 (239, 0.33%), 18 (49, 0.07%), and 13 (55, 0.08%) found in this study is comparable to earlier studies, but the Positive Predictive Values (PPV)-96% for trisomy 21, 98% for trisomy 18, and 53% for trisomy 13-were higher than expected. Findings other than trisomy 21, 18, or 13 were reported on request of the pregnant women; 78% of women chose to have these reported. The number of additional findings was 207 (0.36%); these included other trisomies (101, 0.18%, PPV 6%, many of the remaining 94% of cases are likely confined placental mosaics and possibly clinically significant), structural chromosomal aberrations (95, 0.16%, PPV 32%,) and complex abnormal profiles indicative of maternal malignancies (11, 0.02%, PPV 64%). The implementation of genome-wide NIPT is under debate because the benefits of detecting other fetal chromosomal aberrations must be balanced against the risks of discordant positives, parental anxiety, and a potential increase in (invasive) diagnostic procedures. Our first-year data, including clinical data and laboratory follow-up data, will fuel this debate. Furthermore, we describe how NIPT can successfully be embedded into a national screening program with a single chain for prenatal care including counseling, testing, and follow-up.

First Trimester Combined Test (FTCT) as a Predictor of Gestational Diabetes Mellitus.

Background—The first trimester combined test (FTCT) is an effective screening tool to estimate the risk of fetal aneuploidy. It is obtained by the combination of maternal age, ultrasound fetal nuchal translucency (NT) measurement, and the maternal serum markers free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein A (PAPP-A). However, conflicting data have been reported about the association of FTCT, β-hCG, or PAPP-A with the subsequent diagnosis of gestational diabetes mellitus (GDM). Research design and methods—2410 consecutive singleton pregnant women were retrospectively enrolled in Calabria, Southern Italy. All participants underwent examinations for FTCT at 11–13 weeks (plus 6 days) of gestation, and screening for GDM at 16–18 and/or 24–28 weeks of gestation, in accordance with current Italian guidelines and the International Association Diabetes Pregnancy Study Groups (IADPSG) glycemic cut-offs. Data were examined by univariate and logistic regression analyses. Results—1814 (75.3%) pregnant women were normal glucose tolerant, while 596 (24.7%) were diagnosed with GDM. Spearman univariate analysis demonstrated a correlation between FTCT values and subsequent GDM diagnosis (ρ = 0.048, p = 0.018). The logistic regression analysis showed that women with a FTCT <1:10000 had a major GDM risk (p = 0.016), similar to women with a PAPP-A <1 multiple of the expected normal median (MoM, p = 0.014). Conversely, women with β-hCG ≥2.0 MoM had a reduced risk of GDM (p = 0.014). Conclusions—Our findings indicate that GDM susceptibility increases with fetal aneuploidy risk, and that FTCT and its related maternal serum parameters can be used as early predictors of GDM.

Screening for trisomies by cfDNA testing of maternal blood in twin pregnancy: update of The Fetal Medicine Foundation results and meta‐analysis

To report on the routine clinical implementation of cell-free DNA (cfDNA) analysis of maternal blood for trisomies 21, 18 and 13 in twin pregnancy and to define the performance of the test by combining our results with those identified in a systematic review of the literature. The data for the prospective study were derived from screening for trisomies 21, 18 and 13 in twin pregnancies at 10 + 0 to 14 + 1 weeks' gestation. Two populations were included; first, self-referred women to the Fetal Medicine Centre in London or Brugmann University Hospital in Brussels and, second, women selected for the cfDNA test after routine first-trimester combined testing at one of two National Health Service hospitals in England. This dataset was used to determine the performance of screening for the three trisomies. Search of MEDLINE, EMBASE, CENTRAL (The Cochrane Library), ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP) was carried out to identify all peer-reviewed publications on clinical validation or implementation of maternal cfDNA testing for trisomies 21, 18 and 13 in twin pregnancy. A meta-analysis was then performed using our data and those in the studies identified by the literature search. In our dataset of 997 twin pregnancies with a cfDNA result and known outcome, the test classified correctly 16 (94.1%) of the 17 cases of trisomy 21, nine (90.0%) of the 10 cases of trisomy 18, one (50.0%) of the two cases of trisomy 13 and 962 (99.4%) of the 968 cases without any of the three trisomies. The literature search identified seven relevant studies, excluding our previous papers because their data are included in the current study. In the combined populations of our study and the seven studies identified by the literature search, there were 56 trisomy-21 and 3718 non-trisomy-21 twin pregnancies; the pooled weighted detection rate (DR) and false-positive rate (FPR) were 98.2% (95% CI, 83.2-99.8%) and 0.05% (95% CI, 0.01-0.26%), respectively. In the combined total of 18 cases of trisomy 18 and 3143 non-trisomy-18 pregnancies, the pooled weighted DR and FPR were 88.9% (95% CI, 64.8-97.2%) and 0.03% (95% CI, 0.00-0.33%), respectively. For trisomy 13, there were only three affected cases and two (66.7%) of these were detected by the cfDNA test at a FPR of 0.19% (5/2569). The performance of cfDNA testing for trisomy 21 in twin pregnancy is similar to that reported in singleton pregnancy and is superior to that of the first-trimester combined test or second-trimester biochemical testing. The number of cases of trisomies 18 and 13 is too small for accurate assessment of the predictive performance of the cfDNA test. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

First trimester combined screening in patients with systemic lupus erythematosus: impact of pre-analytical variables on risk assessment

BackgroundPrenatal diagnosis of fetal trisomy 21 and other chromosomal abnormalities is based on invasive tests, such as amniocentesis and chorionic villus sampling, which are carried out in women identified through screening as being at high risk for these abnormalities. The most widely used method of screening is the first-trimester combined test which utilizes maternal age, and measurements of fetal nuchal translucency thickness (NT) and maternal serum pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotropin (hCG).ObjectivesTo assess the influence of SLE on the levels of NT, PAPP-A, and β-hCG and whether any alterations in such levels may increase the rate of false positives and the subsequent number of invasive tests.MethodThis was a prospective first-trimester screening study for trisomies 21, 18, and 13 by a combination of maternal age, fetal nuchal translucency thickness, and serum PAPP-A and β-hCG at King’s College Hospital, London, between March 2006 and February 2011. The study population included 47 cases with maternal SLE and 45,493 without SLE. The results of biomarkers in the SLE and non-SLE groups were compared.ResultsIn the SLE group, compared to the non-SLE group, there were no significant differences in median maternal age, fetal NT, or serum PAPP-A MoM, but serum free β-hCG MoM was increased (1.402, IQR 0.872–2.290 vs 0.994, IQR 0.676–1.508).ConclusionIn first trimester screening for trisomies, the measured value of free ß-hCG should be adjusted for maternal SLE to avoid false positive results and overuse of invasive tests.

Prediction of ischemic placental diseases during the first trimester combined test period: a retrospective cohort of low-risk pregnancies in search of the link between parity and disease

Objective: To assess the predictive power of a multifactorial model established on maternal characteristics, placenta-associated plasma protein A (PAPPA), and the mean uterine artery pulsatility index (Ut A PI) levels for the development of ischemic placental diseases (IPD) during the first-trimester combined test (FTCT) period and to evaluate the strength of some generally accepted clinical risk factors.Method: The studied data were obtained from a retrospective cohort of low-risk singleton pregnancies in the FTCT between 1 August 2016 and 1 December 2017. After routine 11–13-week examinations for FTCT, the Ut A PI was measured and stored electronically. The PAPPA multiple of median (MoM) was obtained as a routine component of aneuploidy screening.Results: A sample of 2493 pregnancies with clearly documented outcomes was studied. Early-onset preeclampsia, late-onset preeclampsia and fetal growth restriction (FGR) were observed in 9 (0.36%), 27 (1.08%), and 41 (1.64%) cases, respectively. With optimum cut-off levels of 0.69 for PAPPA MoM and 2.05 for mean Ut A PI and a false positive rate of 4.9%, IPD cases could be predicted with 83.3% sensitivity and 73.7% specificity. Nulliparity, previous abortion in nulliparous women and first pregnancy from second marriage were not independent risk factors. Maternal age, an interval from the last delivery longer than 6 years, and body mass index were found to be independent risk factors.Conclusion: The IPD showed some common and distinct clinical, laboratory and Doppler findings during the FTCT and were predictable with the help of multifactorial analysis. Some widely accepted risk factors could be affected by various confounders. Because of the increased IPD frequencies, parous women with a time interval from the last delivery of 6 years or longer should be screened as a high-risk group for placental dysfunction-related diseases.

Tamizaje prenatal de trisomía 21 en el Perú por medio del test combinado ampliado contingente en el primer trimestre

Introducción. El tamizaje combinado es la recomendación internacional para el tamizaje prenatal de trisomía 21 en el primer trimestre. El test combinado ampliado agrega uno o más marcadores ecográficos (ducto venoso, flujo tricuspídeo y osificación del hueso nasal). La variedad contingente consiste en dividir la evaluación en dos etapas y usar todos los marcadores solo como contingencia en el grupo con resultado dudoso. Objetivo. Demostrar la efectividad del protocolo de bioquímica contingente propuesto por Kagan. Métodos. Se aplicó el test combinado ampliado en variedad contingente a todas las gestantes con embarazos únicos que acudieron al servicio entre las semanas 11 y 13. Se siguió los criterios publicados por la Fetal Medicine Foundation y la International Society of Ultrasound in Obstetrics and Gynecology. Resultados. Se evaluó 2 578 fetos de embarazos únicos. La evaluación ecográfica inicial identificó 37 (1,4%) fetos con riesgo de 1/50 o mayor (riesgo alto), 1 888 fetos con riesgo menor a 1/1 000 (riesgo bajo) y 653 fetos con riesgo entre 1/51 y 1/1 000 (riesgo intermedio). Como contingencia, al grupo de fetos con riesgo intermedio se les indicó las pruebas bioquímicas (PAPP-a y hCG) que seleccionaron otros 46 (1,8%) fetos con riesgo alto de trisomía 21. Los seis fetos con trisomía 21 en la cohorte estuvieron en el grupo de riesgo alto. Se identificó una población de riesgo basal alto (RBA) (mayores de 36 o 38 años, dependiendo si el riesgo es evaluado en el momento de la ecografía o a término) de trisomía 21, en las cuales no es aplicable el modelo contingente, ya que todas requieren las pruebas bioquímicas. Conclusiones. Nuestros resultados validan el modelo propuesto por Kagan. La tasa de falsos positivos y el tamaño del grupo de riesgo intermedio dependerá de la distribución de la edad materna.

Routine first-trimester screening for fetal trisomies in twin pregnancy: cell-free DNA test contingent on results from combined test.

To report on the routine clinical implementation of cell-free DNA (cfDNA) analysis of maternal blood for trisomies 21, 18 and 13, contingent on the results of the first-trimester combined test in twin pregnancy. Screening for trisomies 21, 18 and 13 was carried out in 959 twin pregnancies by assessment of a combination of maternal age, fetal nuchal translucency thickness, and serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein-A at 11-13 weeks' gestation in two UK NHS hospitals. Women in the high-risk group (risk ≥ 1 in 100) were offered the option of invasive testing, cfDNA testing or no further testing, and those in the intermediate-risk group (risk 1 in 101 to 1 in 2500 in the first phase of the study and 1 in 101 to 1 in 500 in the second phase) were offered cfDNA or no further testing. The trisomic status of the pregnancies was determined by prenatal or postnatal karyotyping or examination of the neonates. In 42 (4.4%) of the 959 pregnancies, there was termination, miscarriage or stillbirth with no known karyotype or there was loss to follow-up. The 917 pregnancies with known trisomic status of both twins included six that were discordant for trisomy 21, four that were discordant for trisomy 18 and 907 with no trisomy 21, 18 or 13. Following combined screening, 47 (5.1%), 203 (22.1%) and 667 (72.7%) of the pregnancies were classified as high risk, intermediate risk and low risk, respectively. The high-risk group included five (83.3%) cases of trisomy 21 and three (75.0%) of trisomy 18. The cfDNA test was carried out in 224 pregnancies and results were provided in 214 (95.5%); this group included six pregnancies with trisomy 21, three with trisomy 18 and 206 with no trisomy 21, 18 or 13. The cfDNA test classified correctly as screen positive all six cases of trisomy 21 and two of the three with trisomy 18, and as screen negative for each of the trisomies all 206 unaffected pregnancies. Contingent screening led to prenatal detection of all cases of trisomy 21 and three of four with trisomy 18. This study has demonstrated the feasibility of introducing cfDNA testing, contingent on the results of the first-trimester combined test for major trisomies, in a routine population of twin pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Improving women\u2019s knowledge about prenatal screening in the era of non-invasive prenatal testing for Down syndrome \u2013 development and acceptability of a low literacy decision aid

BackgroundAccess to information about prenatal screening is important particularly in light of new techniques such as non-invasive prenatal testing (NIPT). This study aimed to develop and examine the acceptability of a low literacy decision aid (DA) about Down syndrome screening among pregnant women with varying education levels and GPs.MethodsWe developed a DA booklet providing information about first-trimester combined testing, maternal serum screening, and NIPT. GPs and women participated in a telephone interview to examine the acceptability of the DA and measure screening knowledge before and after reading the DA. The knowledge measure was designed to assess whether women had understood the gist of the information presented in the decision aid. It comprised conceptual questions (e.g. screening tells you the chance of having a baby with Down syndrome) and numeric questions (e.g. the accuracy of different screening tests).ResultsTwenty-nine women and 18 GPs participated. Regardless of education level, most women found the booklet ‘very’ clearly presented (n = 22, 76%), and ‘very’ informative (n = 23, 80%). Overall, women’s conceptual and numeric knowledge improved after exposure to the DA, from 4% having adequate knowledge to 69%. Women’s knowledge of NIPT also improved after receiving the decision aid, irrespective of education. Most GPs found it ‘very’ clearly presented (n = 13, 72%), and that it would ‘very much’ facilitate decision-making (n = 16, 89%).ConclusionsThe DA was found to be acceptable to women as well as GPs. A comprehensive evaluation of the efficacy of the decision aid compared to standard information is an important next step. Strategies are needed on how to implement the tool in practice.

Special Issue: Abstracts of the ISPD 22nd International Conference on Prenatal Diagnosis and Therapy, Antwerp, Belgium, 8-11 July 2018.

Objectives: In most countries, non-invasive prenatal testing (NIPT) has been introduced commercially without any governmental guidance. In the Netherlands, prenatal screening for fetal anomaly is subject to a governmental license. NIPT has been implemented as part of the TRIDENT studies (Trial by Dutch laboratories for Evaluation of NIPT). TRIDENT-2 aims at offering NIPT to all pregnant women (∼174,000 women/year) within the national prenatal screening program. Since April 2017, women can choose NIPT as a contingent test after first-trimester combined testing (FCT), but may also choose NIPT as first-tier screening test. TheTRIDENT studies evaluate implementation and women's perspectives. Methods: All pregnant women in the Netherlands are offered prenatal screening and are counselled by certified counselors, generally midwives. A first-tier NIPT costs women € 175, comparable to the costs of FCT (∼€ 168). NIPT is performed by three Dutch university clinical genetic laboratories using an in-house validated test. Women can choose to have analysis of chromosomes 21, 18, and 13 without or with a report of incidental findings (findings other than trisomy 21, 13, 18) on the remaining autosomes, respectively, using the 'targeted' or 'whole genome' WISECONDOR pipeline. Sex chromosomes are not analyzed. Results: After 8 months of study, 48,234 tests have been performed (nationwide uptake of prenatal screening by NIPT as first-tier test was 40%), and 98.3% reports successfully issued. Failure rate was less than 2%. Mean turnaround time was 7 working days. 80% of women chose to have all autosomes analyzed. A total of 152 cases of T21 (0.3%), 32 cases of T18 (0.1%), 41 cases of T13 (0.1%), and 158 (0.3%) other chromosomal aberrations were found. First year results (and available follow-up) will be presented at the meeting. Conclusions: The Netherlands are the first country where NIPT is incorporated as a first-line test into a governmentally supported and health care funded prenatal aneuploidy screening program. The incorporation of the test in a university hospital laboratory and clinical service guarantees appropriate counselling and allows for proper follow-up. This 3-year study aims to provide all necessary information for a successful introduction of NIPT within the Dutch National prenatal screening program.

Prenatal reflex DNA screening for trisomies 21, 18, and 13

PurposeThe purpose of the study was to determine the screening performance of prenatal reflex DNA screening for trisomies 21 (T21), 18 (T18), and 13 (T13) as part of a routine service at five hospitals.MethodsWomen who accepted screening had a first-trimester combined test (pregnancy-associated plasma protein A, free β-human chorionic gonadotropin, nuchal translucency interpreted with maternal age). Those with a risk of having an affected pregnancy ≥1 in 800 were reflexed to a DNA sequencing test using stored plasma from the original blood sample, thereby avoiding the need to recall them.ResultsOf 22,812 women screened (including 106 with affected pregnancies), 2,480 (10.9%) were reflexed to DNA testing; 101/106 were detected (69/73 T21, 24/25 T18, and 8/8 T13), a 95% detection rate (95% confidence interval 89–98%) with four false positives (0.02%, 95% confidence interval 0.00–0.05%). The odds of being affected given a positive result were 25:1. Of the 105 screen-positive pregnancies, 91 (87%) had an invasive diagnostic test. Reflex DNA screening avoided up to 530 invasive diagnostic tests compared with using the combined test.ConclusionReflex DNA screening was successfully implemented in routine care, achieving a high detection rate, low false-positive rate, and, consequently, greater safety with fewer invasive diagnostic tests than other methods of screening.