Clinical impact of additional findings detected by genome-wide non-invasive prenatal testing: Follow-up results of the TRIDENT-2 study.

In the TRIDENT-2 study, all pregnant women in the Netherlands are offered genome-wide non-invasive prenatal testing (GW-NIPT) with a choice of receiving either full screening or screening solely for common trisomies. Previous data showed that GW-NIPT can reliably detect common trisomies in the general obstetric population and that this test can also detect other chromosomal abnormalities (additional findings). However, evidence regarding the clinical impact of screening for additional findings is lacking. Therefore, we present follow-up results of the TRIDENT-2 study to determine this clinical impact based on the laboratory and perinatal outcomes of cases with additional findings. Between April 2017 and April 2019, additional findings were detected in 402/110,739 pregnancies (0.36%). For 358 cases, the origin was proven to be either fetal (n = 79; 22.1%), (assumed) confined placental mosaicism (CPM) (n = 189; 52.8%), or maternal (n = 90; 25.1%). For the remaining 44 (10.9%), the origin of the aberration could not be determined. Most fetal chromosomal aberrations were pathogenic and associated with severe clinical phenotypes (61/79; 77.2%). For CPM cases, occurrence of pre-eclampsia (8.5% [16/189] vs 0.5% [754/159,924]; RR 18.5), and birth weight <2.3rd percentile (13.6% [24/177] vs 2.5% [3,892/155,491]; RR 5.5) were significantly increased compared to the general obstetric population. Of the 90 maternal findings, 12 (13.3%) were malignancies and 32 (35.6%) (mosaic) pathogenic copy number variants, mostly associated with mild or no clinical phenotypes. Data from this large cohort study provide crucial information for deciding if and how to implement GW-NIPT in screening programs. Additionally, these data can inform the challenging interpretation, counseling, and follow-up of additional findings.

A PCR-independent approach for mtDNA enrichment and next-generation sequencing: comprehensive evaluation and clinical application.

BACKGROUND: Sequencing the mitochondrial genome has been increasingly important for the investigation of primary mitochondrial diseases (PMD) and mitochondrial genetics. To overcome the limitations originating from PCR-based mtDNA enrichment, we set out to develop and evaluate a PCR-independent approach in this study, named Pime-Seq (PCR-independent mtDNA enrichment and next generation Sequencing). RESULTS: By using the optimized mtDNA enrichment procedure, the mtDNA reads ratio reached 88.0 ± 7.9% in the sequencing library when applied on human PBMC samples. We found the variants called by Pime-Seq were highly consistent among technical repeats. To evaluate the accuracy and reliability of this method, we compared Pime-Seq with lrPCR based NGS by performing both methods simultaneously on 45 samples, yielding 1677 concordant variants, as well as 146 discordant variants with low-level heteroplasmic fraction, in which Pime-Seq showed higher reliability. Furthermore, we applied Pime-Seq on 4 samples of PMD patients retrospectively, and successfully detected all the pathogenic mtDNA variants. In addition, we performed a prospective study on 192 apparently healthy pregnant women during prenatal screening, in which Pime-Seq identified pathogenic mtDNA variants in 4 samples, providing extra information for better health monitoring in these cases. CONCLUSIONS: Pime-Seq can obtain highly enriched mtDNA in a PCR-independent manner for high quality and reliable mtDNA deep-sequencing, which provides us an effective and promising tool for detecting mtDNA variants for both clinical and research purposes.

Prenatal screening after preimplantation genetic testing for aneuploidy: time to evaluate old strategies.

RESEARCH QUESTION: How does first-trimester aneuploidy screening perform in pregnancies achieved through IVF with preimplantation genetic testing for aneuploidy (PGT-A) in a medical setting? DESIGN: This retrospective cohort study was undertaken in a single tertiary care centre between January 2013 and June 2022. In total, 20,237 women had prenatal follow-up at the study centre and were included in the study. The women were divided into three groups: singleton pregnancies conceived through the transfer of a PGT-A-screened euploid embryo (n = 510); singleton pregnancies conceived through IVF without PGT-A (n = 3291); and singleton pregnancies conceived naturally (n = 16,436). RESULTS: The conventional combined screening test for pregnancies conceived through IVF with PGT-A had specificity of 91%; sensitivity could not be calculated as there were no cases of fetal aneuploidy in this group. In 89.1% of pregnancies conceived through IVF with PGT-A with high risk for trisomy 21, 18 or 13, the result was related to advanced maternal age (>35 years at time of screening). CONCLUSIONS: The current screening strategy for trisomies 21, 18 and 13 can generate unnecessary tests in pregnancies achieved through IVF with PGT-A. A new protocol is needed for these patients, with greater weight given to ultrasound markers.

The Hard Palate Sweep: a multiplanar 2-dimensional sonographic method for the prenatal detection of cleft palate.

BACKGROUND: Prenatal diagnosis of cleft palate is challenging. Numerous 2-dimensional and 3-dimensional methods have been proposed to assess the integrity of the fetal palate, yet detection rates remain relatively low. We propose the "Hard Palate Sweep," a novel 2-dimensional method that enables clear demonstration of the entire fetal palate throughout pregnancy, in a single sweep, avoiding acoustic shadows cast by surrounding bones. OBJECTIVE: This study aimed to assess the feasibility and performance of the Hard Palate Sweep, performed throughout pregnancy. STUDY DESIGN: This was a prospective cross-sectional study performed between 2018 and 2022 in pregnant patients referred for a routine or targeted anomaly scan between 13 and 40 weeks of gestation. The presence or absence of a cleft palate was determined using the "Hard Palate Sweep." This was compared with the postnatal palate integrity assessment. Test feasibility and performance indices, including sensitivity, specificity, and positive and negative predictive values were calculated. Offline clips were reviewed by 2 investigators for the assessment of inter- and intraoperator agreement, using Cohen's kappa formula. The study protocol was approved by the institutional ethics committee. All participating patients were informed and provided consent. RESULTS: A total of 676 fetuses were included in the study. The Hard Palate Sweep was successfully performed in all cases, and 19 cases were determined to have a cleft palate. Of these, 13 cases were excluded because postmortem confirmation was not performed, leaving 663 cases available for analysis. Six cases determined to have a cleft palate were confirmed postnatally. In 655 of 657 cases prenatally determined to have an intact palate, this was confirmed postnatally. In the 2 remaining cases, rare forms of cleft palate were diagnosed postnatally, rendering 75% sensitivity, 100% specificity, 100% positive predictive value, and 99.7% negative predictive value for the Hard Palate Sweep (P<.001). There was complete intra- and interoperator agreement (kappa=1; P<.0001). CONCLUSION: The Hard Palate Sweep is a feasible and accurate method for prenatally detecting a cleft palate. It was successfully performed in all attempted cases between 13 and 40 weeks of gestation. This method is reproducible, offering high sensitivity and specificity. Implemented routinely, the Hard Palate Sweep is expected to increase the prenatal detection of cleft palate.

Anticoagulation use is associated with lower fetal fraction and more indeterminate results.

BACKGROUND: Maternal anticoagulation use may increase indeterminate result rates on cell-free DNA-based screening, but existing studies are confounded by inclusion of individuals with autoimmune disease, which alone is associated with indeterminate results. Changes in chromosome level Z-scores are proposed by others as a reason for indeterminate results, but the etiology of this is uncertain. OBJECTIVE: This study aimed to evaluate differences in fetal fraction, indeterminate result rate, and total cell-free DNA concentration in individuals on anticoagulation without autoimmune disease compared with controls undergoing noninvasive prenatal screening. Secondly, using a nested case-control design, we evaluated differences in fragment size, GC-content, and Z-scores to evaluate laboratory-level test characteristics. STUDY DESIGN: This was a retrospective single-institution study of pregnant individuals undergoing cell-free DNA-based noninvasive prenatal screening using low-pass whole-genome sequencing between 2017 and 2021. Individuals with autoimmune disease, suspected aneuploidy, and cases where fetal fraction was not reported were excluded. Anticoagulation included heparin-derived products (unfractionated heparin, low-molecular-weight heparin), clopidogrel, and fondaparinux, with a separate group for those on aspirin alone. An indeterminate result was defined as fetal fraction <4%. We evaluated the association between maternal anticoagulation or aspirin use, and fetal fraction, indeterminate results, and total cell-free DNA concentration using univariate and multivariate analyses, controlling for body mass index, gestational age at sample collection, and fetal sex. For the anticoagulation cohort, we compared laboratory-level test characteristics among cases (on anticoagulation) and a subset of controls. Lastly, we evaluated for differences in chromosome level Z-scores among those on anticoagulation with and without indeterminate results. RESULTS: A total of 1707 pregnant individuals met the inclusion criteria. Of those, 29 were on anticoagulation and 81 were on aspirin alone. For those on anticoagulation, the fetal fraction was significantly lower (9.3% vs 11.7%; P<.01), the indeterminate result rate was significantly higher (17.2% vs 2.7%; P<.001), and the total cell-free DNA concentration was significantly higher (218 pg/µL vs 83.7 pg/µL; P<.001). Among those on aspirin alone, the fetal fraction was lower (10.6% vs 11.8%; P=.04); however, there were no differences in the rate of indeterminate results (3.7% vs 2.7%; P=.57) or total cell-free DNA concentration (90.1 pg/µL vs 83.8 pg/µL; P=.31). After controlling for maternal body mass index, gestational age at sample collection, and fetal sex, anticoagulation was associated with an >8-fold increase in the likelihood of an indeterminate result (adjusted odds ratio, 8.7; 95% confidence interval, 3.1-24.9; P<.001), but not aspirin (adjusted odds ratio, 1.2; 95% confidence interval, 0.3-4.1; P=.8). Anticoagulation was not associated with appreciable differences in cell-free DNA fragment size or GC-content. Although differences in chromosome 13 Z-scores were observed, none were observed for chromosomes 18 or 21, and this difference did not contribute to the indeterminate result call. CONCLUSION: In the absence of autoimmune disease, anticoagulation use, but not aspirin, is associated with lower fetal fraction, higher total cell-free DNA concentration, and higher rates of indeterminate results. Anticoagulation use was not accompanied by differences in cell-free DNA fragment size or GC-content. Statistical differences in chromosome level Z-scores did not clinically affect aneuploidy detection. This suggests a likely dilutional effect by anticoagulation on cell-free DNA-based noninvasive prenatal screening assays contributing to low fetal fraction and indeterminate results, and not laboratory or sequencing-level changes.

The role of cell-free DNA biomarkers and patient data in the early prediction of preeclampsia: an artificial intelligence model.

BACKGROUND: Accurate individualized assessment of preeclampsia risk enables the identification of patients most likely to benefit from initiation of low-dose aspirin at 12 to 16 weeks of gestation when there is evidence for its effectiveness, and enables the guidance of appropriate pregnancy care pathways and surveillance. OBJECTIVE: The primary objective of this study was to evaluate the performance of artificial neural network models for the prediction of preterm preeclampsia (<37 weeks' gestation) using patient characteristics available at the first antenatal visit and data from prenatal cell-free DNA screening. Secondary outcomes were prediction of early-onset preeclampsia (<34 weeks' gestation) and term preeclampsia (≥37 weeks' gestation). METHODS: This secondary analysis of a prospective, multicenter, observational prenatal cell-free DNA screening study (SMART) included singleton pregnancies with known pregnancy outcomes. Thirteen patient characteristics that are routinely collected at the first prenatal visit and 2 characteristics of cell-free DNA (total cell-free DNA and fetal fraction) were used to develop predictive models for early-onset (<34 weeks), preterm (<37 weeks), and term (≥37 weeks) preeclampsia. For the models, the "reference" classifier was a shallow logistic regression model. We also explored several feedforward (nonlinear) neural network architectures with ≥1 hidden layers, and compared their performance with the logistic regression model. We selected a simple neural network model built with 1 hidden layer and made up of 15 units. RESULTS: Of the 17,520 participants included in the final analysis, 72 (0.4%) developed early-onset, 251 (1.4%) preterm, and 420 (2.4%) term preeclampsia. Median gestational age at cell-free DNA measurement was 12.6 weeks, and 2155 (12.3%) had their cell-free DNA measurement at ≥16 weeks' gestation. Preeclampsia was associated with higher total cell-free DNA (median, 362.3 vs 339.0 copies/mL cell-free DNA; P<.001) and lower fetal fraction (median, 7.5% vs 9.4%; P<.001). The expected, cross-validated area under the curve scores for early-onset, preterm, and term preeclampsia were 0.782, 0.801, and 0.712, respectively, for the logistic regression model, and 0.797, 0.800, and 0.713, respectively, for the neural network model. At a screen-positive rate of 15%, sensitivity for preterm preeclampsia was 58.4% (95% confidence interval, 0.569-0.599) for the logistic regression model and 59.3% (95% confidence interval, 0.578-0.608) for the neural network model. The contribution of both total cell-free DNA and fetal fraction to the prediction of term and preterm preeclampsia was negligible. For early-onset preeclampsia, removal of the total cell-free DNA and fetal fraction features from the neural network model was associated with a 6.9% decrease in sensitivity at a 15% screen-positive rate, from 54.9% (95% confidence interval, 52.9-56.9) to 48.0% (95% confidence interval, 45.0-51.0). CONCLUSION: Routinely available patient characteristics and cell-free DNA markers can be used to predict preeclampsia with performance comparable to that of other patient characteristic models for the prediction of preterm preeclampsia. Logistic regression and neural network models showed similar performance.

Placental, maternal, fetal, and technical origins of false-positive cell-free DNA screening results.

The introduction of noninvasive prenatal testing has resulted in substantial reductions to previously accepted false-positive rates of prenatal screening. Despite this, the possibility of false-positive results remains a challenging consideration in clinical practice, particularly considering the increasing uptake of genome-wide noninvasive prenatal testing, and the subsequent increased proportion of high-risk results attributable to various biological events besides fetal aneuploidy. Confined placental mosaicism, whereby chromosome anomalies exclusively affect the placenta, is perhaps the most widely accepted cause of false-positive noninvasive prenatal testing. There remains, however, a substantial degree of ambiguity in the literature pertaining to the clinical ramifications of confined placental mosaicism and its potential association with placental insufficiency, and consequentially adverse pregnancy outcomes including fetal growth restriction. Other causes of false-positive noninvasive prenatal testing include vanishing twin syndrome, in which the cell-free DNA from a demised aneuploidy-affected twin triggers a high-risk result, technical failures, and maternal origins of abnormal cell-free DNA such as uterine fibroids or unrecognized mosaicisms. Most concerningly, maternal malignancies are also a documented cause of false-positive screening results. In this review, we compile what is currently known about the various causes of false-positive noninvasive prenatal testing.

Introduction of a nationwide first-trimester anomaly scan in the Dutch national screening program.

BACKGROUND: A significant proportion of major fetal structural anomalies can be detected in the first trimester by ultrasound examination. However, the test performance of the first-trimester anomaly scan performed in a low-risk population as part of a nationwide prenatal screening program is unknown. Potential benefits of the first-trimester anomaly scan include early detection of fetal anomalies, providing parents with more time for reproductive decision-making. OBJECTIVE: To investigate the uptake, test performance, and time to a final prenatal diagnosis after referral. STUDY DESIGN: A nationwide implementation study was conducted in the Netherlands (November 2021-November 2022). The FTAS was performed between 12+3 and 14+3 weeks of gestation by certified sonographers using a standard protocol. Women were referred to a tertiary care center if anomalies were suspected. Uptake, test performance, and time to a final prenatal diagnosis (days between referral and date of final diagnosis/prognosis for reproductive decision-making) were determined. Test performance was calculated for first-trimester major congenital anomalies, such as anencephaly and holoprosencephaly and all diagnosed anomalies <24 weeks of gestation. RESULTS: The first-trimester anomaly scan uptake was 74.9% (129,704/173,129). In 1.0% (1313/129,704), an anomaly was suspected, of which 54.9% (n=721) had abnormal findings on the detailed first-trimester diagnostic scan and 44.6% (n=586) showed normal results. In 0.5% (n=6), intrauterine fetal death occurred. In the total group of 721 cases with abnormal findings, 332 structural anomalies, 117 genetic anomalies, 82 other findings (abnormal fetal biometry, sonomarkers, placental/umbilical cord anomaly, an-/oligohydramnios), and 189 cases with transient findings (defined as ultrasound findings which resolved <24 weeks of gestation) were found, with 1 case having an unknown outcome. 0.9% (n=1164) of all cases with a normal first-trimester anomaly scan were diagnosed with a fetal anomaly in the second trimester. Test performance included a sensitivity of 84.6% (126/149) for first-trimester major congenital anomalies and 31.6% (537/1701) for all types of anomalies. Specificity for all anomalies was 99.2% (98,055/98,830); positive predictive value 40.9% (537/1312); negative predictive value 98.8% (98,055/99,219); positive likelihood ratio 40.3; negative likelihood ratio 0.7; false positive rate 0.8% (775/98,830), and false negative rate 68.4% (1164/1701). The median time to diagnosis for structural anomalies was 20 days (6-43 days; median gestational age 16+3), for genetic anomalies 17 days (8.5-27.5 days; median gestational age 15+6 weeks), and for first-trimester major congenital anomalies 9 days (5-22 days; median gestational age 14+6 weeks). CONCLUSION: The performance of a newly introduced nationwide first-trimester anomaly scan in a low-risk population showed a high sensitivity for first-trimester major congenital anomalies and a lower sensitivity for all anomalies combined. The program was accompanied by a referral rate of 1.0%, of which 59.1% involved cases where anomalies were either not confirmed or resolved before 24 weeks gestation. Timing of diagnosis was around 16 weeks of gestation for referred cases. To evaluate the balance between benefits and potential harm of the first-trimester anomaly scan within a nationwide prenatal screening program, it is essential to assess the effectiveness of the program over time and to consider the perspectives of both women and their partners, as well as healthcare professionals.

Optimizing recovery of Haemophilus influenzae from vaginal-rectal specimens and determining carriage rates in pregnant women.

PURPOSE: Haemophilus influenzae (HINF), primarily non-typeable H. influenzae: (NTHi), is an important cause of neonatal sepsis and meningitis. The goal of this study was to investigate the point prevalence of HINF vaginal-rectal carriage in pregnant women, which could impact neonatal health. METHODS: Simulated vaginal-rectal swabs were cultured and tested to establish optimal recovery methods for HINF. These methods were then applied to vaginal-rectal swabs from a prospective cohort of pregnant women (n = 300) undergoing routine Group B Streptococcus: (GBS) screening. Both culture and PCR were used for detection of HINF. Subject demographics, reproductive history, and genitourinary test results were documented. A retrospective surveillance study was conducted to determine incidence of invasive neonatal HINF infections from 7/1/2017-6/30/2023. RESULTS: HINF was recovered from 42/42 (100%) simulated vaginal-rectal swabs at 2-45 CFU/plate via direct plating onto chocolate and chocolate + bacitracin agar. HINF was rarely recovered following LIM broth enrichment at 0-75 CFU/plate in 1/42 (2.4%) simulated swabs, but was recovered from BHI/Fildes broth enrichment in 22/42 (52%) specimens at high abundance (> 100 CFU/plate). Among pregnant women prospectively screened for HINF, the median age was 29 (IQR, 24-33) years and gestational age was 36 (IQR, 34-36) weeks. HINF was recovered in 1 of 300 prospective specimens by culture but 0/100 by PCR. A six-year retrospective analysis showed there were seven total cases of neonatal sepsis and majority of HINF was isolated from respiratory specimens followed by blood/CSF overall. CONCLUSION: This study established a sensitive culture method for recovering HINF from vaginal-rectal swab specimens and demonstrated low prevalence of HINF carriage rate in pregnant women. These findings highlight the need for further research to pinpoint the source for transmission of HINF to neonates.

Atypicality index as an add-on to combined first-trimester screening for chromosomal aberrations.

OBJECTIVES: To compute a set of atypicality indices based on combined first-trimester screening (cFTS) markers and second-trimester estimated fetal weight (EFW), and to demonstrate their potential in identifying pregnancies at reduced or increased risk of chromosomal aberrations following a low-risk cFTS result. METHODS: The atypicality index quantifies the unusualness of an individual set of measurements relative to a reference distribution and can be computed from any variables or measurements available. A score of 0% on the atypicality index represents the most typical profiles, while a score of 100% indicates the highest level of atypicality. From the Danish Fetal Medicine Database, we retrieved data on all pregnant women seen for cFTS in the Central Denmark Region between January 2008 and December 2018. All pregnancies with a cytogenetic or molecular analysis obtained prenatally, postnatally or following pregnancy loss or termination were identified. A first-trimester atypicality index (AcFTS) was computed based on nuchal translucency (NT) thickness, maternal serum free ß-human chorionic gonadotropin (ß-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Furthermore, a second-trimester index (AcFTS + EFW) was computed from cFTS markers and EFW from a routine second-trimester anomaly scan. All pregnancies were stratified into subgroups based on their atypicality levels and their cFTS risk estimates. The risk of chromosomal aberrations in each subgroup was then compared with the overall prevalence, and a graphical presentation of the multivariate measurement profiles was developed. RESULTS: We retrieved data on 145 955 singleton pregnancies, of which 9824 (6.7%) were genetically examined. Overall, 1 in 122 (0.82% (95% CI, 0.77-0.87%)) of all pregnancies seen for cFTS were affected by a fetal chromosomal aberration, and in screen-negative pregnancies (cFTS trisomy 21 risk < 1 in 100 and/or trisomy 18/13 risk < 1 in 50), 0.41% (95% CI, 0.38-0.44%) were affected. In screen-negative pregnancies with a typical first-trimester profile (AcFTS < 80%), the risk of chromosomal aberrations was significantly reduced (0.28%) compared with the overall risk. The risk of chromosomal aberrations increased with higher atypicality index to 0.49% (AcFTS [80-90%)), 1.52% (AcFTS [90-99%)) and 4.44% (AcFTS ≥ 99%) and was significantly increased in the two most atypical subgroups. The same applied for the second-trimester atypicality index, with risks of chromosomal aberrations of 0.76% and 4.16% in the two most atypical subgroups (AcFTS + EFW [90-99%) and AcFTS + EFW ≥ 99%, respectively). CONCLUSIONS: As an add-on to cFTS, the atypicality index identifies women with typical measurement profiles, which may provide reassurance, whereas atypical profiles may warrant specialist referral and further investigation. In pregnancies identified as low risk on cFTS but with a highly atypical distribution of NT, PAPP-A and ß-hCG, the risk of a chromosomal aberration is substantially increased. The atypicality index optimizes the interpretation of pre-existing prenatal screening profiles and is not limited to cFTS markers or EFW. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Uterine fibroids and non-informative cell-free DNA screening results.

OBJECTIVE: Uterine fibroids are monoclonal tumors, which are often genetically abnormal and associated with false-positive genome-wide cell-free DNA (cfDNA) screening results, particularly when large. It is plausible that fibroids may also increase the risk of cfDNA failure by affecting fetal fraction or due to their genetic anomalies confounding cfDNA algorithms. We aimed to investigate a possible association between fibroids and cfDNA non-informative results. METHODS: This was a retrospective cohort study of women undergoing cfDNA screening for fetal chromosomal abnormalities between 2013 and 2020, comparing pregnancies with vs without uterine fibroids recorded on any obstetric ultrasound before 24 weeks' gestation. Univariable and multivariable logistic regression models were used to investigate the association between fibroids and cfDNA failure, adjusting for gestational age, maternal age, weight and height at blood sampling, mode of conception, multiple gestation and test platform (chromosome-selective or genome-wide). Analyses were stratified according to the number of fibroids and total fibroid volume. The impact of fibroids on fetal fraction was assessed using linear regression, adjusting for the same covariates. RESULTS: Among 19 818 pregnancies undergoing cfDNA screening, fibroids were reported in 2038 (10.28%) and cfDNA failure at the first screening attempt occurred in 228 (1.15%) pregnancies. Non-informative results occurred in 1.96% of pregnancies with fibroids and 1.06% of pregnancies without fibroids (adjusted odds ratio (aOR), 2.40 (95% CI, 1.65-3.48)). The risk of failure in the first screening attempt increased progressively with the number of fibroids (aOR, 5.05 (95% CI, 2.29-11.13) in women with four or more fibroids) and total fibroid volume, with greater than a 5-fold and 14-fold increase in risk among women with fibroid volumes of 100.1-400 mL (aOR, 5.52 (95% CI, 2.30-13.25)) and > 400 mL (aOR, 14.80 (95% CI, 4.50-48.69)), respectively. Although test failure was more common with chromosome-selective than genome-wide screening, fibroids similarly increased the risk of failure of both screening platforms. Compared to pregnancies without fibroids, those with fibroids had a fetal fraction on average 0.61% lower (adjusted mean difference, -0.61% (95% CI, -0.77% to -0.45%)). CONCLUSION: Uterine fibroids are associated with lower fetal fraction and an increased risk of cfDNA screening failure. The strength of this association increases with increasing fibroid number and volume. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Decoding 22q11.2: prenatal profiling and first-trimester risk assessment in Danish nationwide cohort.

OBJECTIVES: To examine the distribution of nuchal translucency thickness (NT), free ß-human chorionic gonadotropin (ß-hCG) and pregnancy-associated plasma protein-A (PAPP-A) in pregnancies with a fetal 22q11.2 aberration. Furthermore, the performance of combined first-trimester screening (cFTS) and a new risk algorithm targeting 22q11.2 deletions in detecting affected pregnancies was evaluated. Finally, prenatal malformations and pregnancy outcome were assessed. METHODS: This was a nationwide registry-based cohort study of all pregnancies that underwent prenatal screening with a due date between January 2008 and December 2018 in Denmark. All cases with a fetal 22q11.2 deletion or duplication (hg19 chr22:18.9mio-25.0mio) diagnosed pre- or postnatally or following pregnancy loss or termination of pregnancy were retrieved from the Danish Cytogenetic Central Register and linked with pregnancy data from the Danish Fetal Medicine Database. Fetal and maternal characteristics, including cFTS results and pregnancy outcome, of pregnancies with any 22q11.2 deletion or duplication (LCR22-A to -H) and pregnancies with a classic deletion or duplication (LCR22-A to -D) diagnosed by chromosomal microarray were compared with those of a chromosomally normal reference group. A risk algorithm was developed for assessing patient-specific risks for classic 22q11.2 deletions based on NT, PAPP-A and ß-hCG. Detection rates and false-positive rates at different risk cut-offs were calculated. RESULTS: We included data on 143 pregnancies with a fetal 22q11.2 aberration, of which 97 were deletions (54 classic) and 46 were duplications (32 classic). NT was significantly increased in fetuses with a classic deletion (mean, 1.89 mm), those with any deletion (mean, 1.78 mm) and those with any duplication (mean, 1.86 mm) compared to the reference group (mean, 1.65 mm). ß-hCG multiples of the median (MoM) was decreased in all 22q11.2 subgroups compared with the reference group (mean, 1.02) and reached significance in pregnancies with a classic deletion and those with any deletion (mean, 0.77 and 0.71, respectively). PAPP-A MoM was significantly decreased in pregnancies with a classic duplication and those with any duplication (mean, 0.57 and 0.63, respectively), and was significantly increased in pregnancies with a classic deletion and those with any deletion (mean, 1.34 and 1.16, respectively), compared to reference pregnancies (mean, 1.01). The screen-positive rate by cFTS was significantly increased in pregnancies with a classic deletion (13.7%), any deletion (12.5%), a classic duplication (46.9%) or any duplication (37.8%) compared to the reference group (4.5%). A risk algorithm targeting classic 22q11.2 deletions more than doubled the prenatal detection rate of classic 22q11.2 deletions, but with a substantial increase in the false-positive rate. Structural malformations were detected in 41%, 35%, 17% and 25% of the pregnancies with a classic deletion, any deletion, classic duplication or any duplication, respectively. Pregnancy loss occurred in 40% of pregnancies with a classic deletion and 5% of those with a classic duplication diagnosed prenatally or following pregnancy loss. CONCLUSIONS: The distribution of cFTS markers in pregnancies with a classic 22q11.2 duplication resembles that of the common trisomies, with decreased levels of PAPP-A. However, classic 22q11.2 deletions are associated with increased levels of PAPP-A, which likely limits early prenatal detection using the current cFTS risk algorithm. The scope for improving early detection of classic 22q11.2 deletions using targeted risk algorithms based on NT, PAPP-A and ß-hCG is limited. This demonstrates the capability, but also the limitations, of cFTS markers in detecting atypical chromosomal anomalies, which is important knowledge when designing new prenatal screening programs. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Cost-utility analysis of prenatal diagnosis of congenital cardiac diseases using deep learning.

BACKGROUND: Deep learning (DL) is a new technology that can assist prenatal ultrasound (US) in the detection of congenital heart disease (CHD) at the prenatal stage. Hence, an economic-epidemiologic evaluation (aka Cost-Utility Analysis) is required to assist policymakers in deciding whether to adopt the new technology. METHODS: The incremental cost-utility ratios (CUR), of adding DL assisted ultrasound (DL-US) to the current provision of US plus pulse oximetry (POX), was calculated by building a spreadsheet model that integrated demographic, economic epidemiological, health service utilization, screening performance, survival and lifetime quality of life data based on the standard formula: CUR = Increase in Intervention Costs - Decrease in Treatment costs Averted QALY losses of adding DL to US & POX US screening data were based on real-world operational routine reports (as opposed to research studies). The DL screening cost of 145 USD was based on Israeli US costs plus 20.54 USD for reading and recording screens. RESULTS: The addition of DL assisted US, which is associated with increased sensitivity (95% vs 58.1%), resulted in far fewer undiagnosed infants (16 vs 102 [or 2.9% vs 15.4%] of the 560 and 659 births, respectively). Adoption of DL-US will add 1,204 QALYs. with increased screening costs 22.5 million USD largely offset by decreased treatment costs (20.4 million USD). Therefore, the new DL-US technology is considered "very cost-effective", costing only 1,720 USD per QALY. For most performance combinations (sensitivity > 80%, specificity > 90%), the adoption of DL-US is either cost effective or very cost effective. For specificities greater than 98% (with sensitivities above 94%), DL-US (& POX) is said to "dominate" US (& POX) by providing more QALYs at a lower cost. CONCLUSION: Our exploratory CUA calculations indicate the feasibility of DL-US as being at least cost-effective.

Disparities in integrating non-invasive prenatal testing into antenatal healthcare in Australia: a survey of healthcare professionals.

BACKGROUND: Non-invasive prenatal testing (NIPT) has been clinically available in Australia on a user-pays basis since 2012. There are numerous providers, with available tests ranging from targeted NIPT (only trisomies 21, 18, and 13 +/- sex chromosome aneuploidy) to genome-wide NIPT. While NIPT is being implemented in the public health care systems of other countries, in Australia, the implementation of NIPT has proceeded without public funding. The aim of this study was to investigate how NIPT has been integrated into antenatal care across Australia and reveal the successes and challenges in its implementation in this context. METHODS: An anonymous online survey was conducted from September to October 2022. Invitations to participate were sent to healthcare professionals (HCPs) involved in the provision of NIPT in Australia through professional society mailing lists and networks. Participants were asked questions on their knowledge of NIPT, delivery of NIPT, and post-test management of results. RESULTS: A total of 475 HCPs responded, comprising 232 (48.8%) obstetricians, 167 (35.2%) general practitioners, 32 (6.7%) midwives, and 44 (9.3%) genetic specialists. NIPT was most commonly offered as a first-tier test, with most HCPs (n = 279; 60.3%) offering it to patients as a choice between NIPT and combined first-trimester screening. Fifty-three percent (n = 245) of respondents always offered patients a choice between NIPT for the common autosomal trisomies and expanded (including genome-wide) NIPT. This choice was understood as supporting patient autonomy and informed consent. Cost was seen as a major barrier to access to NIPT, for both targeted and expanded tests. Equitable access, increasing time demands on HCPs, and staying up to date with advances were frequently reported as major challenges in delivering NIPT. CONCLUSIONS: Our findings demonstrate substantial variation in the clinical implementation of NIPT in Australia, including in the offers of expanded screening options. After a decade of clinical use, Australian clinicians still report ongoing challenges in the clinical and equitable provision of NIPT.

Outcomes of pregnancies with varying levels of nuchal translucency measurements: A population-based retrospective study in Ontario, Canada.

INTRODUCTION: Nuchal translucency prenatal ultrasound is widely used to screen for chromosomal abnormalities. An elevated nuchal translucency has been associated with adverse outcomes such as pregnancy loss; however, extant studies investigating these associations have had important limitations, including selection bias. This study aimed to investigate the association between nuchal translucency measurements and pregnancy outcome, specifically, a composite of pregnancy loss, termination, stillbirth, or neonatal death. MATERIAL AND METHODS: This was a population-based retrospective cohort study conducted with data from the prescribed perinatal registry in Ontario, Canada, Better Outcomes Registry & Network. All singleton pregnancies with an estimated date of delivery from September 1, 2016, to March 31, 2021, and multiple marker screening including a nuchal translucency were included. Pregnancies with measurements 2.0- < 2.5 mm, 2.5- < 3.0 mm, 3.0- < 3.5 mm, 3.5- < 5.0 mm, 5.0- < 6.5 mm, and ≥6.5 mm were compared to a reference group with measurements <2.0 mm. We used multivariable modified Poisson regression models with robust variance estimation to estimate associations between nuchal translucency measurement and pregnancy outcome, with adjustment for age at estimated date of delivery and gestational age at screening. RESULTS: There were 414 268 singleton pregnancies included in the study. The risk of pregnancy loss, termination, stillbirth, or neonatal death increased with increasing levels of nuchal translucency measurements, with an adjusted risk ratio (aRR) of 11.9 (95% confidence interval (CI) 9.9, 14.3) in the group with measurements 3.5- < 5.0 mm. When pregnancies with diagnosed chromosomal abnormalities were excluded, this association remained strong, with an aRR of 6.4 (95% CI 4.8, 8.5). Among pregnancies with a live birth, those with a higher nuchal translucency measurement (>5.0 mm vs. <2.0 mm) were also at increased risk of adverse perinatal outcomes such as admission to the neonatal intensive care unit and APGAR score <7. CONCLUSIONS: In this population-based study using robust methods to reduce the risk of selection bias, we found that pregnancies with increased nuchal translucency measurements are less likely to result in a live birth, even with the exclusion of chromosomal abnormalities. Pregnancies with increased nuchal translucency measurements that resulted in a live birth may also be at increased risk of adverse perinatal outcomes.

Pregnancies with 'double-positive' multiple marker screening results: a population-based study in Ontario, Canada.

BACKGROUND: Multiple marker screening is offered to pregnant individuals in many jurisdictions to screen for trisomies 21 and 18. On occasion, the result is 'double-positive'-a screening result that is unexpectedly positive for both aneuploidies. Although this occurs rarely, the paucity of available evidence about the outcomes of these pregnancies hinders patient counselling. This study aimed to investigate the association of double-positive results with preterm birth and other adverse perinatal outcomes. METHODS: We conducted a population-based retrospective cohort study of pregnancies with an estimated date of delivery from September 1, 2016, to March 31, 2021, using province-wide perinatal registry data in Ontario, Canada. Pregnancies with double-positive screening results where trisomies 21 and 18 were ruled-out were compared to pregnancies with screen negative results for both aneuploidies. We used modified Poisson regression models with robust variance estimation to examine the association of double positive results with preterm birth and secondary outcomes. RESULTS: From 429 540 pregnancies with multiple marker screening, 863 (0.2%) had a double-positive result; trisomies 21 and 18 were ruled out in 374 pregnancies, 203 of which resulted in a live birth. Among the pregnancies in the double-positive group resulting in a live birth, the risk of preterm birth was increased compared to pregnancies with a screen negative result: adjusted risk ratio (aRR) 2.6 (95%CI 2.0-3.6), adjusted risk difference (aRD) 10.5% (95%CI 5.4-15.7). In a sensitivity analysis excluding all diagnosed chromosomal abnormalities, the risk of preterm birth remained elevated to a similar degree: aRR 2.6 (95%CI 1.9-3.7), aRD 10.0% (95%CI 4.8-15.3). The risk of other adverse perinatal outcomes was also higher, including the risk of chromosomal abnormalities other than trisomies 21 and 18: aRR 81.1 (95%CI 69.4-94.8), aRD 34.0% (95%CI 29.2-38.8). Pregnancies with double-positive results were also less likely to result in a live birth, even when excluding all diagnosed chromosomal abnormalities; and at increased risk of adverse perinatal outcomes for those resulting in a live birth. CONCLUSION: Although rare, double-positive multiple marker screening results are associated with an increased risk of preterm birth and other adverse perinatal outcomes, even when excluding all identified chromosomal abnormalities.

"We're Going to Book This for You": Threats to Informed Decision-Making in the Down Syndrome Determination Experience.

OBJECTIVES: To identify and describe threats to informed decision-making at key junctures of the Down syndrome (DS) determination experience. METHODS: We conducted 32 narrative interviews with 42 participants (10 couples and 22 individuals). Participants relayed their stories of receiving their child's or a prospective child's DS determination. Interviews were recorded, transcribed verbatim, and analyzed thematically. RESULTS: We identified the following 5 threats to informed decision-making: routinization of screening, screening for reassurance's sake, equating an openness to screening with an openness to testing and termination, misunderstanding and miscommunicating about probability, and a lack of up-to-date, accurate, neutral information. CONCLUSIONS: The results contribute to an existing body of literature on the DS determination experience with a uniquely Canadian lens. The threats outline how well-intended counselling can ultimately undermine reproductive autonomy and informed decision-making. With knowledge of how these seemingly harmless behaviours threaten informed decision-making and reproductive autonomy, care providers can modify their counselling to lessen their impact.

Implementation of Multiple Marker Screening for Preterm Preeclampsia in a Single Tertiary Obstetric Centre.

OBJECTIVES: Early assessment of pregnant individuals for risk of preterm preeclampsia (PE) is possible at the 11-14 week ultrasound visit using a validated multiple marker algorithm, allowing timely use of preventative low-dose acetylsalicylic acid (LDA) in high-risk patients. With no established early screening program for preterm PE in Canada, our objectives were to assess the acceptability and operational impact of routine screening for preterm PE during the 11-14 week ultrasound visit, evaluate uptake and adherence to LDA when recommended, and assess screening performance. METHODS: A prospective implementation study of preterm PE screening among pregnant patients at the ultrasound unit of a tertiary obstetric centre in Toronto, Canada. RESULTS: A total of 1057 patients were screened, with an acceptance rate of 87.1%. First-trimester ultrasound appointment time increased by a median time of 7 minutes (Interquartile range 6-9). By 16 weeks gestation, 88.7% of high-risk patients had started LDA, with adherence of 88.7%‒94.6% from 16‒36 weeks. Satisfaction with counselling was ≥7/10 in more than 95% of patients. There were 7 cases of preterm PE (0.73%), 3 in the low-risk group (0.35%), and 4 in the high-risk group (4.1%). When accounting for LDA use, the treatment-adjusted detection rate was 78.6%. CONCLUSIONS: We demonstrate successful implementation of a validated, effective screening and prevention program for preterm PE as a first step in the implementation of a broader program adaptable for cultural, access/equity considerations, and marker availability.

NIPT for adult-onset conditions: Australian NIPT users' views.

Noninvasive prenatal testing (NIPT) has become widely available in recent years. While initially used to screen for trisomies 21, 18, and 13, the test has expanded to include a range of other conditions and will likely expand further. This paper addresses the ethical issues that arise from one particularly controversial potential use of NIPT: screening for adult-onset conditions (AOCs). We report data from our quantitative survey of Australian NIPT users' views on the ethical issues raised by NIPT for AOCs. The survey ascertained support for NIPT for several traits and conditions including AOCs. Participants were then asked about their level of concern around implications of screening for AOCs for the future child and parent(s). Descriptive and comparative data analyses were conducted. In total, 109 respondents were included in data analysis. The majority of respondents expressed support for NIPT screening for preventable (70.9%) and nonpreventable AOCs (80.8%). Most respondents indicated concern around potential harmful impacts associated with NIPT for AOCs, including the psychological impact on the future child and on the parent(s). Despite this, the majority of participants thought that continuation of a pregnancy known to be predisposed to an AOC is ethically acceptable. The implications of these data are critically discussed and used to inform the normative claim that prospective parents should be given access to NIPT for AOCs. The study contributes to a body of research debating the ethical acceptability and regulation of various applications of NIPT as screening panels expand.

Is intermediate risk really intermediate? Comparison of karyotype and non-invasive prenatal testing results of pregnancies at intermediate risk of trisomy 21 on maternal serum screening.

The purpose of this study was to assess the additional contribution of karyotyping compared with genome-wide non-invasive prenatal testing (NIPT) for pregnancies at intermediate risk for trisomy 21 (T21), calculated using the maternal serum screening without major structural anomalies detected through sonography. Karyotype results of all pregnancies undergoing invasive prenatal diagnostic testing between January 2013 and March 2022 were obtained from a large hospital-based laboratory. Pregnancies with no major structural anomalies on ultrasound (including soft markers) and an intermediate risk for T21 on maternal serum screening were included in this study. The additional contribution of karyotyping for abnormal karyotype results was calculated after excluding results that could theoretically be identified with genome-wide NIPT. Among the 511 pregnancies analyzed, 13 (2.54%) were found to have abnormal karyotype results, 9 (1.76%) of which could theoretically have been detected with genome-wide NIPT. Within the cohort, 6/263 (2.28%) of women aged 35 years and older, and 3/248 (1.20%) of women younger than 35 years had results that could have been detected with genome-wide NIPT. After excluding results detectable using genome-wide NIPT, the additional contribution of karyotyping was found as 4/502 (0.79%) for the entire cohort, 2/257 (0.77%) for women aged 35 years and older, 2/245 (0.81%) for women younger than 35 years. Of the 511 examined pregnancies at intermediate risk for T21 by maternal serum screening, genome-wide NIPT would have failed to detect 4 of 13 abnormal karyotype results. The findings hold importance in guiding couples' informed decision-making processes regarding their choice of genetic screening and diagnostic testing in case of intermediate risk for T21.