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.

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.

Confined Placental Mosaicism Detected With Non-Invasive Prenatal Testing: Is There an Association Between Mosaic Ratio and Pregnancy Outcome?

OBJECTIVE: Confined placental mosaicism (CPM) is associated with an increased risk for pregnancy complications, such as fetal growth restriction (FGR), preterm birth and hypertensive disorders. Pregnancies with possible CPM can be identified with non-invasive prenatal testing (NIPT). We performed a retrospective cohort study to investigate whether the mosaic ratio, as calculated with the Veriseq v2 used for NIPT, can predict adverse pregnancy outcomes in cases of CPM. METHOD: A mosaic ratio for trisomies detected by NIPT and obstetric data such as fetal growth, structural fetal anomalies and birthweight were retrospectively studied in a cohort of patients with CPM diagnosed between February 2021 and October 2023. Structural and sex chromosomal aberrations were not included in this study. RESULTS: Of 122 CPM cases, 52 cases (42.6%) showed adverse perinatal outcomes, including FGR, low birthweight, hypertensive disorders, or preterm birth. A significantly higher mosaic ratio was found in the adverse outcome group compared to those with normal outcome, but a clear-cut threshold could not be set, except potentially for trisomy 16. CONCLUSION: There is an association between the mosaic ratio and adverse pregnancy outcomes in cases of CPM. However, without a clear-cut threshold, it cannot be used for the individual patient for differentiation between CPM with and without clinical consequences.

Fetal Speckle Tracking Echocardiography Measured Global Longitudinal Strain and Strain Rate in Congenital Heart Disease: A Systematic Review and Meta-Analysis.

Fetal two-dimensional speckle tracking echocardiography (2D-STE) is a novel technique that provides information on fetal heart function by measuring global longitudinal strain (GLS) and global longitudinal strain rate (GLSR). These features assess the longitudinal deformity of the fetal cardiac wall. 2D-STE is shown to be of prognostic value in children and adults with congenital heart disease (CHD). Therefore, its importance in fetal life should also be considered. This systematic review and meta-analysis provides an overview of the literature on 2D-STE (GLS/GLSR) in fetuses with CHD, focusing on the left and right ventricles (LV/RV). Findings indicated that LV-GLS was significantly lower in fetuses with coarctation of the aorta (CoA) and Tetralogy of Fallot (ToF) compared to controls. Conversely, fetuses with a single left ventricle exhibited higher LV-GLS. RV-GLS was significantly lower in fetuses with hypoplastic left heart syndrome (HLHS) and ToF compared to controls. LV-GLSR was significantly lower in fetuses with CoA. Overall, considerable heterogeneity was observed, possibly due to differences in study design. More prospective longitudinal studies on 2D-STE in fetuses with CHD, considering heterogeneity parameters, could offer better insights into this promising technique.

The role of confined placental mosaicism in fetal growth restriction: A retrospective cohort study.

OBJECTIVE: To evaluate which cytogenetic characteristics of confined placental mosaicism (CPM) detected in the first trimester chorionic villi and/or placentas in terms of chromosome aberration, cell lineage involved and trisomy origin will lead to fetal growth restriction and low birthweight. METHODS: Cohort study using routinely collected perinatal data and cytogenetic data of non-invasive prenatal testing, the first trimester chorionic villi sampling and postnatal placentas. RESULTS: 215 CPM cases were found. Fetal growth restriction (FGR) and low birthweight below the 10th percentile (BW < p10) were seen in 34.0% and 23.1%, respectively. Excluding cases of trisomy 16, 29.1% showed FGR and 17.9% had a BW < p10. The highest rate of FGR and BW < p10 was found in CPM type 3, but differences with type 1 and 2 were not significant. FGR and BW < p10 were significantly more often observed in cases with meiotic trisomies. CONCLUSION: There is an association between CPM and FGR and BW < p10. This association is not restricted to trisomy 16, neither to CPM type 3, nor to CPM involving a meiotic trisomy. Pregnancies with all CPM types and origins should be considered to be at increased risk of FGR and low BW < p10. A close prenatal fetal monitoring is indicated in all cases of CPM.

The High Diagnostic Yield of Prenatal Exome Sequencing Followed by 3400 Gene Panel Analysis in 629 Ongoing Pregnancies With Ultrasound Anomalies.

BACKGROUND: The aim of this study was to evaluate the diagnostic yield of routine exome sequencing (ES) in fetuses with ultrasound anomalies. METHODS: We performed a retrospective analysis of the ES results of 629 fetuses with isolated or multiple anomalies referred in 2019-2022. Variants in a gene panel consisting of approximately 3400 genes associated with multiple congenital anomalies and/or intellectual disability were analyzed. We used trio analysis and filtering for de novo variants, compound heterozygous variants, homozygous variants, X-linked variants, variants in imprinted genes, and known pathogenic variants. RESULTS: Pathogenic and likely pathogenic variants (class five and four, respectively) were identified in 14.0% (88/629, 95% CI 11.5%-16.9%) of cases. In the current cohort, the probability of detecting a monogenetic disorder was ∼1:7 (88/629, 95% CI 1:8.7-1:5.9), ranging from 1:9 (49/424) in cases with one major anomaly to 1:5 (32/147) in cases with multiple system anomalies. CONCLUSIONS: Our results indicate that a notable number of fetuses (1:7) with ultrasound anomalies and a normal chromosomal microarray have a (likely) pathogenic variant that can be detected through prenatal ES. These results warrant implementation of exome sequencing in selected cases, including those with an isolated anomaly on prenatal ultrasound.

Periconceptional maternal folate status and the impact on embryonic head and brain structures: the Rotterdam Periconceptional Cohort.

RESEARCH QUESTION: Does periconceptional maternal folate status influence the size of human embryonic head and brain structures? DESIGN: The study population was selected from the Rotterdam Periconceptional Cohort conducted at the Erasmus MC. Three-dimensional (3D) ultrasound scans were performed at 9 and 11 weeks of gestational age. Using 3D ultrasound datasets, head volume, head circumference, diencephalon (DTD), mesencephalon (MTD) and left/right telencephalon (TTL/TTR) measurements were performed offline using a virtual reality technique and specialized 3D software. Maternal venous blood samples were taken at study entry to determine red blood cell (RBC) folate. Linear regression models were applied to investigate associations between RBC folate status and embryonic head and brain structures adjusted for gestational age, alcohol use, smoking, maternal age and mode of conception. RESULTS: RBC folate measurements were available for 144 of the 166 singleton pregnancies eligible for analysis. RBC folate quartiles were defined: 466-1078 nmol/l (Q1), 1079-1342 nmol/l (Q2), 1343-1594 nmol/l (Q3), 1595-2919 nmol/l (Q4), with Q3 being used as reference. At 11 weeks of gestational age, head volume was largest in Q1 (ß = 0.866; P = 0.004) and Q4 (ß = 0.764; P = 0.007). In addition, head circumference at 11 weeks of gestational age was significantly larger in Q4 (ß = 2.745; P = 0.03). There were no statistical significantly associations between the RBC folate quartiles and the sizes of the DTD, MTD, TTL and TTR. CONCLUSIONS: U-shaped associations were shown between the periconceptional maternal RBC folate status and embryonic head volume and head circumference. The clinical implication of these findings needs further investigation.

How to deal with uncertainty in prenatal genomics: A systematic review of guidelines and policies.

Exome sequencing (ES) enhanced the diagnostic yield of genetic testing, but has also increased the possibility of uncertain findings. Prenatal ES is increasingly being offered after a fetal abnormality is detected through ultrasound. It is important to know how to handle uncertainty in this particularly stressful period. This systematic review aimed to provide a comprehensive overview of guidelines available for addressing uncertainty related to prenatal chromosomal microarray (CMA) and ES. Ten uncertainty types associated with prenatal ES and CMA were identified and defined by an international multidisciplinary team. Medline (all) and Embase were systematically searched. Laboratory scientists, clinical geneticists, psychologists, and a fetal medicine specialist screened the papers and performed the data extraction. Nineteen papers were included. Recommendations generally emphasized the importance of trio analysis, clinical information, data sharing, validation and re-analysis, protocols, multidisciplinary teams, genetic counselling, whether to limit the possible scope of results, and when to report particular findings. This systematic review helps provide a vocabulary for uncertainties, and a compass to navigate uncertainties. Prenatal CMA and ES guidelines provide a strong starting point for determining how to handle uncertainty. Gaps in guidelines and recommendations were identified and discussed to provide direction for future research and policy making.

IVF with or without ICSI and the impact on human embryonic brain development: the Rotterdam Periconceptional Cohort.

STUDY QUESTION: Does IVF with or without ICSI (IVF/ICSI) treatment impact the development of embryonic brain structures? SUMMARY ANSWER: Our results show associations between IVF/ICSI treatment, smoking and slightly increased sizes of early human embryonic brain structures. WHAT IS KNOWN ALREADY: The number of IVF/ICSI procedures is increasing worldwide and is associated with higher risks of obstetric and perinatal complications in pregnancies. STUDY DESIGN, SIZE, DURATION: One hundred seventy-five women with a singleton pregnancy were included in the Rotterdam Periconceptional Cohort (Predict study). PARTICIPANTS/MATERIALS, SETTING, METHODS: Self-reported questionnaires, verified by a research assistant at enrollment, provided information on periconceptional maternal characteristics and mode of conception. Three-dimensional ultrasound (3D-US) examinations were performed at 9 and 11 weeks of gestational age (GA). Diencephalon total diameter (DTD), mesencephalon total diameter (MTD) and telencephalon thickness on the left and right site (TTL/TTR) were measured offline in standardized planes using 4D View software. Linear regression models with adjustment for GA, maternal age, body mass index, moment of initiation of folic acid supplement use and smoking were used to study associations between mode of conception and embryonic brain measurements at 9 and 11 weeks of GA. MAIN RESULTS AND ROLE OF CHANCE: A total of 276 3D-US scans of 166 participants, of which 50 conceived through IVF/ICSI, were included for embryonic brain measurements. Success rates of the DTD and MTD measurements were between 67% and 73% and of the TTL/TTR between 52% and 57%. In the fully adjusted model, we found that at 11 weeks of GA, the MTD (ß = 0.264, 95% CI = 0.101; 0.427, P < 0.01) and TTR (ß = 0.075, 95% CI = 0.001; 0.149, P < 0.05) sizes were larger in IVF/ICSI pregnancies. In addition, smoking also resulted in larger TTL measurements at 11 weeks of GA (ß = 0.095, 95% CI= 0.005; 0.186, P < 0.05). LIMITATIONS, REASONS FOR CAUTION: The implications of these small deviations on brain functioning need further investigation. WIDER IMPLICATIONS OF THE FINDINGS: Enlargement of attention for prenatal brain development and postnatal neurodevelopmental outcome after IVF/ICSI treatment. STUDY FUNDING/COMPETING INTERESTS: This study was funded by the Department of Obstetrics and Gynecology, Erasmus MC, and Sophia research foundation for Medical Research, Rotterdam, the Netherlands (SSWO grant number 644). No competing interests are declared. TRIAL REGISTRATION NUMBER: N/A.

The potential diagnostic yield of whole exome sequencing in pregnancies complicated by fetal ultrasound anomalies.

INTRODUCTION: The aim of this retrospective cohort study was to determine the potential diagnostic yield of prenatal whole exome sequencing in fetuses with structural anomalies on expert ultrasound scans and normal chromosomal microarray results. MATERIAL AND METHODS: In the period 2013-2016, 391 pregnant women with fetal ultrasound anomalies who received normal chromosomal microarray results, were referred for additional genetic counseling and opted for additional molecular testing pre- and/or postnatally. Most of the couples received only a targeted molecular test and in 159 cases (40.7%) whole exome sequencing (broad gene panels or open exome) was performed. The results of these molecular tests were evaluated retrospectively, regardless of the time of the genetic diagnosis (prenatal or postnatal). RESULTS: In 76 of 391 fetuses (19.4%, 95% CI 15.8%-23.6%) molecular testing provided a genetic diagnosis with identification of (likely) pathogenic variants. In the majority of cases (91.1%, 73/76) the (likely) pathogenic variant would be detected by prenatal whole exome sequencing analysis. CONCLUSIONS: Our retrospective cohort study shows that prenatal whole exome sequencing, if offered by a clinical geneticist, in addition to chromosomal microarray, would notably increase the diagnostic yield in fetuses with ultrasound anomalies and would allow early diagnosis of a genetic disorder irrespective of the (incomplete) fetal phenotype.

Implementing non-invasive prenatal testing (NIPT) in the Netherlands: An interview study exploring opinions about and experiences with societal pressure, reimbursement, and an expanding scope.

The noninvasive prenatal test (NIPT) as the first trimester prenatal screening (FTS) for trisomies 21, 18, and 13 is offered to all pregnant women in the Netherlands. NIPT using genome sequencing allows for an expansion of the scope of FTS and the introduction of NIPT gives rise to ethical and societal concerns about deliberated decision-making, pressure to engage in screening, and possible lack of equal access due to the financial contribution (€175) to NIPT. We explored the opinions and experiences of pregnant women, who were offered FTS, about these concerns, and the possibility of a broadened scope. Nineteen pregnant women representing a diversity of backgrounds were interviewed using a semi-structured interview guide. Eight women did not opt for prenatal screening while 11 did (NIPT = 4, combined test = 7). Women experienced a free choice to accept or decline prenatal screening, despite sometimes receiving advice from others. Prior to pretest counseling, some women had already deliberated about what an abnormal test result would mean to them. Others accepted or declined FTS without deliberation. The current Dutch policy of requiring a co-payment was acceptable to some, who believed that it functioned as a threshold to think carefully about FTS. Others were concerned that a financial threshold would lead to unequal access to screening. Finally, pregnant women found it difficult to formulate opinions on the scope of FTS, because of lack of knowledge. Life expectancy, severity, and treatability were considered important criteria for the inclusion of a condition in NIPT.

Termination of pregnancy for fetal anomalies: Parents' preferences for psychosocial care.

OBJECTIVE: To investigate, from the perspective of women and partners, at what stage of a termination of pregnancy (TOP) for fetal anomalies psychosocial care (PSC) is most meaningful, what topics should be discussed, and who should provide PSC. METHOD: A cross-sectional retrospective cohort study was conducted with a consecutive series of 76 women and 36 partners, who completed a semi-structured online questionnaire. RESULTS: Overall, women expressed a greater need for PSC than their partners. Parents expressed a preference for receiving support from a maternal-fetal medicine specialist to help them understand the severity and consequences of the anomalies found and to counsel them in their decision regarding termination. Parents showed a preference for support from mental healthcare providers to help with their emotional responses. Forty-one percent of the women visited a psychosocial professional outside of the hospital after the TOP, indicating a clear need for a well-organised aftercare. CONCLUSION: Different disciplines should work together in a complementary way during the diagnosis, decision making, TOP, and aftercare stages. Parents' need for PSC should be discussed at the beginning of the process. During aftercare, attention should be paid to grief counselling, acknowledgement of the lost baby's existence, and possible future pregnancies.

Placental studies elucidate discrepancies between NIPT showing a structural chromosome aberration and a differently abnormal fetal karyotype.

OBJECTIVE: Placental cytogenetic studies may reveal the origin of discordant noninvasive prenatal testing (NIPT). We performed placental studies to elucidate discordances between NIPT showing a structural chromosome aberration and the fetus having a different chromosome aberration in three cases. METHOD: Diagnostic testing with genomic SNP microarray was performed in three cases with NIPT showing a duplication on 4q (case 1), a terminal deletion of 13q (case 2), and a terminal deletion of 15q (case 3). Placental studies involved SNP array analysis of cytotrophoblast and mesenchymal core of chorionic villi of four placental quadrants. Clinical follow-up was performed as well. RESULTS: Amniotic fluid revealed a different structural chromosome aberration than predicted by NIPT: a terminal 2q deletion (case 1), a segmental uniparental isodisomy of 13q (case 2), and a terminal duplication of 15q and of 13q (case 3). Placental studies revealed the aberration detected with NIPT in the cytotrophoblast, whereas the fetal karyotype was confirmed in the placental mesenchymal core. CONCLUSION: Our study shows that targeted cytogenetic investigations for confirmation of NIPT showing a microscopically visible structural chromosome aberration should be avoided, since another aberration, even a submicroscopic one or one involving another chromosome, may be present in the fetus.

Unexpected finding of uniparental disomy mosaicism in term placentas: Is it a common feature in trisomic placentas?

OBJECTIVE: Non-invasive prenatal testing (NIPT) detects placental chromosome aberrations. When amniocentesis reveals a normal karyotype, confined placental mosaicism (CPM) may be assumed. In order to confirm this, placental cytogenetic studies were performed. METHOD: NIPT was conducted in the course of the Dutch TRIDENT study. Placentas of 10 cases with NIPT results indicating an autosomal trisomy and showing a normal (N = 9) or low mosaic karyotype (N = 1) in amniotic fluid (AF) were investigated. The cytotrophoblast as well as the mesenchymal core of two to four placental chorionic villi biopsies were studied with single nucleotide polymorphism (SNP) array. Clinical outcome data were collected. RESULTS: In 10/10 cases, CPM was proven. In 3/10 cases trisomy/uniparental disomy (UPD)/biparental disomy (BPD) mosaicism was discovered. In 2/3 cases, all three cell lines were present in the placenta, whereas BPD was found in AF. In 1/3 cases trisomy 22/UPD22 was present in AF while trisomy 22/BPD22 mosaicism was found in the placenta. Five of 10 pregnancies were affected with pre-eclampsia, low birth weight, preterm delivery, and/or congenital malformations. CONCLUSION: The presence of trisomy/UPD/BPD mosaicism in 3/10 cases that we investigated proves that trisomic zygote rescue may involve multiple rescue events during early embryogenesis. UPD mosaicism, when present in crucial fetal tissues, may explain the abnormal phenotype in undiagnosed cases.

Accuracy of fetal sex determination in the first trimester of pregnancy using 3D virtual reality ultrasound.

PURPOSE: Early detection of fetal sex is becoming more popular. The aim of this study was to evaluate the accuracy of fetal sex determination in the first trimester, using 3D virtual reality. METHODS: Three-dimensional (3D) US volumes were obtained in 112 pregnancies between 9 and 13 weeks of gestational age. They were offline projected as a hologram in the BARCO I-Space and subsequently the genital tubercle angle was measured. Separately, the 3D US aspect of the genitalia was examined for having a male or female appearance. RESULTS: Although a significant difference in genital tubercle angles was found between male and female fetuses, it did not result in a reliable prediction of fetal gender. Correct sex prediction based on first trimester genital appearance was at best 56%. CONCLUSION: Our results indicate that accurate determination of the fetal sex in the first trimester of pregnancy is not possible, even using an advanced 3D US technique.

The influence of SNP-based chromosomal microarray and NIPT on the diagnostic yield in 10,000 fetuses with and without fetal ultrasound anomalies.

Prenatal diagnostics has been impacted by technological changes in the past decade, which have affected the diagnostic yield. The aim of this study was to evaluate the impact of SNP array and noninvasive prenatal testing (NIPT) on the diagnostic yield and the number of invasive tests in our center. The frequency of pathogenic fetal unbalanced chromosome aberrations was studied in 10,005 cases referred for prenatal testing in 2009-2015. Chromosomal SNP microarray analysis replaced karyotyping in all invasively tested pregnancies and since 2014 a choice between NIPT and diagnostic testing with microarray was offered to women with an increased risk for common aneuploidy. The introduction of microarray led to an additional yield of submicroscopic pathogenic chromosome aberrations: 3.6% in fetuses with ultrasound anomalies and 1.9% in fetuses without ultrasound anomalies. The introduction of NIPT led to a decrease of invasive tests and of diagnostic yield. Moreover, a diagnostic delay in about 1:350 cases was observed. Since 20%-33% of pathogenic fetal chromosome aberrations are different from the common aneuploidies and triploidy, whole-genome analysis should be offered after invasive sampling. Because NIPT (as a second screening) has led to a decreased diagnostic yield, it should be accompanied by an appropriate pretest counseling.

Prenatal influence of congenital heart defects on trajectories of cortical folding of the fetal brain using three-dimensional ultrasound.

OBJECTIVE: The objective of the study is to investigate the prenatal influence of congenital heart defects (CHD) on trajectories of fetal cortical folding using three-dimensional ultrasound (3D US). METHOD: We included 20 CHD fetuses and 193 controls for studying the fetal brain at 22, 26 and 32 weeks' gestational age (GA). The Sylvian, insula and parieto-occipital fissure (POF) depths were measured using 3D US, and reliability was evaluated. Doppler indices of the umbilical artery and middle cerebral artery were measured to calculate the cerebro-placental ratio. Associations between CHD and cortical folding were estimated using linear mixed models. RESULTS: Brain fissure measurements were successful in over 80% of 3D US scans, except for the POF at 32 weeks' GA (65%). All measurements showed a good reliability (intraclass correlation coefficients > 0.84). Growth trajectories of the left insula depth (ß = -2.753, 95% CI = -5.375; -0.130, p = 0.040) and right POF (ß = -3.762, 95% CI = -7.178; -0.346, p = 0.031) were decreased in CHD compared with controls, whereas growth rates were increased (ß = 0.014, 95% CI = 0.001; 0.027, p = 0.036 and ß = 0.024, 95% CI = 0.007; 0.041, p = 0.006). In contrast to controls, we found no associations between cerebro-placental ratio and cortical folding in CHD. CONCLUSION: Fetal cortical folding can be evaluated reliably by measuring brain fissure depths. Trajectories of cortical folding between 22 and 32 weeks' GA seem to be influenced by CHD. © 2017 John Wiley & Sons, Ltd.

Size-based molecular diagnostics using plasma DNA for noninvasive prenatal testing.

Noninvasive prenatal testing using fetal DNA in maternal plasma is an actively researched area. The current generation of tests using massively parallel sequencing is based on counting plasma DNA sequences originating from different genomic regions. In this study, we explored a different approach that is based on the use of DNA fragment size as a diagnostic parameter. This approach is dependent on the fact that circulating fetal DNA molecules are generally shorter than the corresponding maternal DNA molecules. First, we performed plasma DNA size analysis using paired-end massively parallel sequencing and microchip-based capillary electrophoresis. We demonstrated that the fetal DNA fraction in maternal plasma could be deduced from the overall size distribution of maternal plasma DNA. The fetal DNA fraction is a critical parameter affecting the accuracy of noninvasive prenatal testing using maternal plasma DNA. Second, we showed that fetal chromosomal aneuploidy could be detected by observing an aberrant proportion of short fragments from an aneuploid chromosome in the paired-end sequencing data. Using this approach, we detected fetal trisomy 21 and trisomy 18 with 100% sensitivity (T21: 36/36; T18: 27/27) and 100% specificity (non-T21: 88/88; non-T18: 97/97). For trisomy 13, the sensitivity and specificity were 95.2% (20/21) and 99% (102/103), respectively. For monosomy X, the sensitivity and specificity were both 100% (10/10 and 8/8). Thus, this study establishes the principle of size-based molecular diagnostics using plasma DNA. This approach has potential applications beyond noninvasive prenatal testing to areas such as oncology and transplantation monitoring.

Trial by Dutch laboratories for evaluation of non-invasive prenatal testing. Part I-clinical impact.

OBJECTIVE: To evaluate the clinical impact of nationwide implementation of genome-wide non-invasive prenatal testing (NIPT) in pregnancies at increased risk for fetal trisomies 21, 18 and 13 (TRIDENT study). METHOD: Women with elevated risk based on first trimester combined testing (FCT ≥ 1:200) or medical history, not advanced maternal age alone, were offered NIPT as contingent screening test, performed by Dutch University Medical laboratories. We analyzed uptake, test performance, redraw/failure rate, turn-around time and pregnancy outcome. RESULTS: Between 1 April and 1 September 2014, 1413/23 232 (6%) women received a high-risk FCT result. Of these, 1211 (85.7%) chose NIPT. One hundred seventy-nine women had NIPT based on medical history. In total, 1386/1390 (99.7%) women received a result, 6 (0.4%) after redraw. Mean turn-around time was 14 days. Follow-up was available in 1376 (99.0%) pregnancies. NIPT correctly predicted 37/38 (97.4%) trisomies 21, 18 or 13 (29/30, 4/4 and 4/4 respectively); 5/1376 (0.4%) cases proved to be false positives: trisomies 21 (n = 2), 18 (n = 1) and 13 (n = 2). Estimated reduction in invasive testing was 62%. CONCLUSION: Introduction of NIPT in the Dutch National healthcare-funded Prenatal Screening Program resulted in high uptake and a vast reduction of invasive testing. Our study supports offering NIPT to pregnant women at increased risk for fetal trisomy. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.