Risk of miscarriage following amniocentesis or chorionic villus sampling: systematic review of literature and updated meta-analysis

Guideline No. 456: Prenatal Screening for Fetal Chromosomal Anomalies

OBJECTIVE

To review the available prenatal aneuploidy screening options and to provide updated clinical guidelines for reproductive care providers.

TARGET POPULATION

All pregnant persons receiving counselling and providing informed consent for prenatal screening.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline should increase clinician competency to offer counselling for prenatal screening options and provide appropriate interventions. Given the variety of available options for prenatal screening with different performance, cost, and availability across Canada, appropriate counselling is of paramount importance to offer the best individual choice to Canadian pregnant persons. Prenatal screening may cause anxiety, and the decisions about prenatal diagnostic procedures are complex given the potential risk of fetal loss.

EVIDENCE

Published literature was retrieved through searches of Medline, PubMed, and the Cochrane Library in and prior to July 2023, using an appropriate controlled vocabulary (prenatal diagnosis, amniocentesis, chorionic villi sampling, non-invasive prenatal screening) and key words (prenatal screening, prenatal genetic counselling). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies written in English and published from January 1995 to July 2023.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See Appendix A (Tables A1 for definitions and A2 for interpretations).

INTENDED AUDIENCE

Health care providers involved in prenatal screening, including general practitioners, obstetricians, midwives, maternal-fetal medicine specialists, geneticists, and radiologists.

SOCIAL MEDIA ABSTRACT

Non-invasive prenatal screening is the most accurate method for detecting major aneuploidies. It is not universally available in the public health system and has some limitations.

Directive clinique N° 456 : Dépistage prénatal des anomalies chromosomiques fœtales

OBJECTIF

Examiner les possibilités de dépistage prénatal des aneuploïdies et fournir des lignes directrices cliniques actualisées aux prestataires de soins de la reproduction.

POPULATION CIBLE

Personnes enceintes qui reçoivent des conseils sur le dépistage prénatal et qui donnent leur consentement éclairé. BéNéFICES, RISQUES ET COûTS: La mise en application des recommandations de la présente directive devrait améliorer la compétence des cliniciens pour conseiller les patientes sur les options de dépistage prénatal et leur donner accès aux interventions indiquées. Compte tenu de la diversité des options disponibles pour le dépistage prénatal, dont la fiabilité, le coût et la disponibilité varient d'un bout à l'autre du Canada, il est primordial d'offrir des conseils appropriés pour permettre aux personnes enceintes canadiennes de faire un choix éclairé. Le dépistage prénatal peut être source d'anxiété, et les décisions relatives aux examens de diagnostic prénatal sont complexes compte tenu du risque de perte fœtale. DONNéES PROBANTES: La littérature publiée avant la fin de juillet 2023 a été colligée par des recherches dans les bases de données Medline, PubMed et Cochrane Library au moyen de termes (prenatal diagnosis, amniocentesis, chorionic villi sampling, non-invasive prenatal screening) et mots clés (prenatal screening, prenatal genetic counselling) pertinents et validés. Les seuls résultats retenus proviennent de revues systématiques, d'essais cliniques randomisés ou comparatifs et d'études observationnelles publiés en anglais entre janvier 1995 et juillet 2023. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Voir l'annexe A (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et faibles). PROFESSIONNELS CONCERNéS: Professionnels de la santé impliqués dans le dépistage prénatal, y compris les omnipraticiens, les obstétriciens, les sages-femmes, les spécialistes en médecine fœto-maternelle, les généticiens et les radiologues. RéSUMé DES MéDIAS SOCIAUX: Le test génomique prénatal non invasif est la méthode la plus fiable pour détecter les aneuploïdies majeures. Il n'est pas universellement disponible dans le système de santé publique et comporte certaines limites.

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.

Ethical considerations in prenatal genomic testing

This paper discusses ethical issues arising in the context of prenatal genomic testing. While genomic information in the prenatal context might increase reproductive choice, e.g. to better understand a phenotype detected during screening, the availability of ever broader screens, even in the absence of a suspicion of abnormality, will generate increasingly complex and uncertain information. This raises questions of how much and what information should be provided prior to testing and what information should be returned (and to whom) once testing has been performed. As prenatal genomic testing becomes broader and more routine, the information generated will have more often implications not only for the fetus, but also for the parents, siblings and the wider family, raising questions about professionals' responsibilities. Further challenges discussed in this paper include access to genomic testing and justice, as well as ongoing management and post-pregnancy follow-up. The paper highlights the importance of taking into account the particular difficulties that arise in the context of prenatal genomic testing: the uncertainty of the information while choices are binary (to continue with or to terminate pregnancy); the time pressure due to the statutory limits on the availability of termination; and the impact the testing of the fetus has on the woman's body and life.

Chapter 2: Non-invasive prenatal diagnosis

Non-invasive prenatal diagnosis of monogenic disorders is becoming integrated into routine clinical care for many indications. This is carried out by testing cell-free DNA extracted from the plasma portion of a maternal blood sample. The cell-free DNA is low in concentration, and consists of a mixture of maternal and fetally-derived DNA which are not easy to separate. Methods used therefore need to be rapid, sensitive and specific, including real-time PCR, digital PCR and next generation sequencing with complex algorithms. Testing may be required for pregnancies with an increased chance of a monogenic disorder due to family history or carrier status, or where there are specific abnormalities identified by ultrasound scan. In these situations, testing is considered to be diagnostic and therefore does not require confirmation by invasive testing. With increased access to genomic technologies, and more diagnoses for rare disease patients, future demand for NIPD and possibilities during pregnancy will continue.

Comparative analysis of the application with the combination of CMA and karyotype in routine and late amniocentesis

PURPOSE

This is a retrospective comparative study. We aimed to analyze the results of karyotype and chromosomal microarray analysis (CMA) of amniotic fluid across different gestational weeks and evaluate the clinical value in prenatal diagnosis, particularly in the late pregnancies.

METHODS

Samples from 580 pregnant women of 18-23 weeks of gestation (mid-gestation group) and 196 pregnant women of 24-32 weeks of gestation (late group) were performed both standard G-band karyotype analysis and CMA.

RESULTS

Among the 580 pregnant women in the routine group, the most common indications were positive Down's screening (213/580, 36.7%), followed by advanced maternal age (196/580, 33.8%); while fetal structural anomalies on ultrasonography were the top reason for amniocentesis in the late group (56/196, 28.6%). In the routine group, the total detection rate was 12.1% (70/580), of which 4.1% (24/580) were identified by karyotype analysis and 11.2% (65/580) by CMA. The total detection rate was 15.3% (30/196) in the late group, of which 5.1% (10/196) were detected by karyotype analysis, and 14.3% (28/196) by CMA.

CONCLUSION

Karyotype analysis and CMA are complementary in detecting chromosomal abnormalities. Amniotic cavity puncture in the karyotype analysis in 18-23 weeks of gestation and 24-32 weeks of gestation is safe and effective, more obvious effect on the latter.

Prenatal Diagnosis of Cleft Lip and Palate: A Retrospective Study

Cleft lip and/or palate are prevalent congenital anomalies. Early and accurate diagnosis allows proper case management. The Objective: This retrospective cohort study aimed to investigate the association between cleft lip and palate and other congenital anomalies. Methods: This study analyzed 17 pregnancies prenatally diagnosed with cleft lip and palate. The investigations consisted of ultrasound examination, fetal karyotyping through amniocentesis, and family tree analysis. In the presence of an abnormal fetal karyotype, the parental karyotype was also indicated. Results: Of the 17 cases identified, 9 (52.94%) were syndromic and 8 (47.06%) were non-syndromic. The genetic syndromes identified in association with cleft lip and palate in this study included translocation syndrome (one case), Patau syndrome, trisomy 13 (seven cases), and Edwards syndrome, mosaic trisomy 18 (one case). Conclusions: A comprehensive approach ensures a thorough assessment and accurate diagnosis. Early detection and a multidisciplinary approach allow appropriate case management.

Mothers' reflections on the diagnosis and birth of their child with Down syndrome: Variability based on the timing of the diagnosis

Previous research has examined parents' reflections on their child's Down syndrome diagnosis based on whether the diagnosis was provided prenatally or after birth, revealing few significant differences; by comparison, few studies have examined parents' reflections on the birth of the child in relation to the timing of the diagnosis. This study was conducted to examine whether mothers differentially reported on and rated the diagnosis, birth, and most recent birthday of their child with DS based on when the diagnosis was provided. Forty-four American mothers of children with DS discussed the birth of their child, when they learned of their child's DS diagnosis, and their child's most recent birthday with a researcher. Participants also completed online questionnaires on which they rated the events and indicated how they felt about the events at the time of their occurrence and at the time of the study. The results revealed that participants who received a prenatal diagnosis of DS for their child reflected differently-and seemingly more positively-on their child's birth relative to participants who received a postnatal diagnosis. These differences were evident when considering participant ratings, emotion language used when discussing the events, and feeling states characterizing how participants felt about the events at the time of their occurrence and at the time of the study. Given these group differences, medical professionals should carefully consider the conditions under which they provide mothers with diagnostic information and support services after a child is born.

Potential efficacy of digital polymerase chain reaction for non-invasive prenatal screening of autosomal aneuploidies: a systematic review and meta-analysis

BACKGROUND

Digital Polymerase Chain Reaction (dPCR) presents a promising approach for quantifying DNA and analyzing copy number variants, particularly in non-invasive prenatal testing. This method offers a streamlined and time-efficient procedure in contrast to the widely used next-generation sequencing for non-invasive prenatal testing. Studies have reported encouraging results for dPCR in detecting fetal autosomal aneuploidies. Consequently, this systematic review aimed to evaluate the effectiveness of dPCR in screening for trisomy 21, 18, and 13.

METHODS

A systematic search was conducted in PubMed, Web of Sciences, and Embase for relevant articles published up to December 30, 2023. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was utilized for the quality assessment of the included articles. Furthermore, a bivariate random-effect regression model was used to conduct a meta-analysis on the utility of dPCR for trisomy 21 screening.

RESULTS

A total of 9 articles were included in this review, with all of them assessing the utility of dPCR in trisomy 21 screening, and 2 and 1 studies conducting additional analysis on the screening abilities of dPCR for trisomy 18 and 13, respectively. A bivariate random-effects model calculated pooled sensitivity and specificity with a 95% confidence interval (CI). Meta-analysis of 6 studies comparing trisomy-21 screening with karyotyping demonstrated dPCR's pooled sensitivity of 98% [95% CI: 94 -100] and specificity of 99% [95% CI: 99 -100]. While conducting a meta-analysis for trisomy 13 and 18 proved impractical, reported values for sensitivity and specificity were favorable.

CONCLUSIONS

These findings suggest that dPCR holds promise as an effective tool for non-invasive prenatal testing, presenting a less time-consuming and intricate alternative to next-generation sequencing. However, further research is necessary to evaluate dPCR's applicability in clinical settings and to delineate its specific advantages over next-generation sequencing. This study contributes valuable insights into the potential of dPCR for enhancing prenatal screening methodologies.

TRIAL REGISTRATION

The protocol of this study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on 7/3/2024, with a registration code of CRD42024517523.

Brain Metabolite Differences in Fetuses With Cytomegalovirus Infection: A Magnetic Resonance Spectroscopy Study

BACKGROUND

Cytomegalovirus (CMV) is the most common intrauterine infection and may be associated with unfavorable outcomes. While some CMV-infected fetuses may show gross or subtle brain abnormalities on MRI, their clinical significance may be unclear. Conversely, normal development cannot be guaranteed in CMV-infected fetuses with normal MRI.

PURPOSE

To assess brain metabolite differences in CMV-infected fetuses using magnetic resonance spectroscopy (MRS).

STUDY TYPE

Retrospective.

SUBJECTS

Out of a cohort of 149 cases, 44 with maternal CMV infection, amniocentesis results, and good-quality MRS were included. CMV-infected fetuses with positive polymerase chain reaction (PCR) (N = 35) were divided based on MRI results as follows: typical brain abnormalities (gross findings, N = 8), exclusive white matter hyperintense signal (WMHS) on T2-weighted images (subtle findings, N = 7), and normal MRI (N = 20). Uninfected fetuses (negative PCR) with normal MRI were included as controls (N = 9).

FIELD STRENGTH

3 T, T2-weighted half Fourier single-shot turbo spin-echo (HASTE), T2-weighted true fast imaging with steady-state free precession (TrueFISP), T1- and T2*-weighted fast low angle shot (FLASH), and 1H-MRS single-voxel point resolved spectroscopy (PRESS) sequences.

ASSESSMENT

MRI findings were assessed by three radiologists, and metabolic ratios within the basal ganglia were calculated using LCModel.

STATISTICAL TESTS

Analysis of covariance test with Bonferroni correction for multiple comparisons was used to compare metabolic ratios between groups while accounting for gestational age. A P-value <0.05 was deemed significant.

RESULTS

MRS was successfully acquired in 63% of fetuses. Substantial agreement was observed between radiologists (Fleiss' kappa [k] = 0.8). Infected fetuses with gross MRI findings exhibited significantly reduced tNAA/tCr ratios (0.64 ± 0.08) compared with infected fetuses with subtle MRI findings (0.85 ± 0.19), infected fetuses with normal MRI (0.8 ± 0.14) and controls (0.81 ± 0.15). No other significant differences were detected (P ≥ 0.261).

CONCLUSION

Reduced tNAA/tCr within the apparently normal brain tissue was detected in CMV-infected fetuses with gross brain abnormalities, suggesting extensive brain damage. In CMV-infected fetuses with isolated WMHS, no damage was detected by MRS.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 3.

The impact of confined placental mosaicism on prenatal cell-free DNA screening: Insights from a monocentric study of 99 cases

INTRODUCTION

Confined placental mosaicism (CPM) is thought to be one of the main sources of false-positive prenatal cell-free DNA (cfDNA) screening results, but extensive and systematic studies to prove this statement are limited. We evaluate the contribution of CPM to false-positive prenatal cfDNA screening results in the largest cohort published to date.

METHOD

We systematically offered postnatal analysis on placenta and umbilical cord to women who had a negative amniocentesis following a positive prenatal cfDNA screening result. A standardized protocol was used in which (when available) biopsies were taken at five locations in the placenta and umbilical cord.

RESULTS

We analyzed a series of 99 placentas. CPM could be confirmed in 32.3 % of cases (32/99). CPM was detected across all subtypes of chromosomal aberrations (common and rare autosomal trisomies, sex chromosome abnormalities, copy number variations and autosomal monosomies). A lower detection rate was present in umbilical cord biopsies in comparison with placental biopsies. When comparing different sections of the placenta, no clear difference could be observed with regard to the probability of CPM being present nor to the grade of mosaicism.

DISCUSSION

We confirm an important role for CPM in explaining false-positive prenatal cfDNA screening results. Placental regional differences are common. Given its limited clinical relevance, we do however not advocate placental studies in a diagnostic setting.

Comparative analysis of obstetric, perinatal, and neurodevelopmental outcomes following chorionic villus sampling and amniocentesis

Background

The risks of invasive prenatal tests are reported in previous studies such as miscarriage, fetal anomalies, and bleeding. However, few compare short-term and long-term outcomes between invasive tests. This study aims to investigate obstetric, perinatal, and children's neurodevelopmental outcomes following chorionic villus sampling (CVS) or amniocentesis in singleton pregnancy.

Methods

This retrospective cohort study included healthy singleton pregnancies underwent transabdominal CVS (gestational age [GA] at 10-13 weeks) or amniocentesis (GA at 15-21 weeks) at a single medical center between 2012 and 2022. Only cases with normal genetic results were eligible. Short-term and long-term neurodevelopmental outcomes were evaluated.

Results

The study included 200 CVS cases and 498 amniocentesis cases. No significant differences were found in body mass index, parities, previous preterm birth, conception method, and cervical length (CL) before an invasive test between the groups. Rates of preterm labor, preterm premature rupture of the membranes, preterm birth, neonatal survival, neonatal short-term morbidities, and long-term neurodevelopmental delay were similar. However, the CVS group had a higher rate of cervical cerclage due to short CL before 24 weeks (7.0%) compared to the amniocentesis group (2.4%). CVS markedly increased the risk of cervical cerclage due to short CL (adjusted odd ratio [aOR] = 3.17, 95%CI [1.23-8.12], p = 0.016), after considering maternal characteristics.

Conclusion

Performing CVS resulted in a higher incidence of cerclage due to short cervix or cervical dilatation compared to amniocentesis in singleton pregnancies. This highlights the importance of cautious selection for CVS and the necessity of informing women about the associated risks beforehand.

Amniocentesis in pregnancies at or beyond 24 weeks: an international multicenter study

BACKGROUND

Amniocentesis for genetic diagnosis is most commonly done between 15 and 22 weeks of gestation but can be performed at later gestational ages. The safety and genetic diagnostic accuracy of amniocentesis have been well-established through numerous large-scale multicenter studies for procedures before 24 weeks, but comprehensive data on late amniocentesis remain sparse.

OBJECTIVE

To evaluate the indications, diagnostic yield, safety, and maternal and fetal outcomes associated with amniocentesis performed at or beyond 24 weeks of gestation.

STUDY DESIGN

We conducted an international multicenter retrospective cohort study examining pregnant individuals who underwent amniocentesis for prenatal diagnostic testing at gestational ages between 24w0d and 36w6d. The study, spanning from 2011 to 2022, involved 9 referral centers. We included singleton or twin pregnancies with documented outcomes, excluding cases where other invasive procedures were performed during pregnancy or if amniocentesis was conducted for obstetric indications. We analyzed indications for late amniocentesis, types of genetic tests performed, their results, and the diagnostic yield, along with pregnancy outcomes and postprocedure complications.

RESULTS

Of the 752 pregnant individuals included in our study, late amniocentesis was primarily performed for the prenatal diagnosis of structural anomalies (91.6%), followed by suspected fetal infection (2.3%) and high-risk findings from cell-free DNA screening (1.9%). The median gestational age at the time of the procedure was 28w5d, and 98.3% of pregnant individuals received results of genetic testing before birth or pregnancy termination. The diagnostic yield was 22.9%, and a diagnosis was made 2.4 times more often for fetuses with anomalies in multiple organ systems (36.4%) compared to those with anomalies in a single organ system (15.3%). Additionally, the diagnostic yield varied depending on the specific organ system involved, with the highest yield for musculoskeletal anomalies (36.7%) and hydrops fetalis (36.4%) when a single organ system or entity was affected. The most prevalent genetic diagnoses were aneuploidies (46.8%), followed by copy number variants (26.3%) and monogenic disorders (22.2%). The median gestational age at delivery was 38w3d, with an average of 59 days between the procedure and delivery date. The overall complication rate within 2 weeks postprocedure was 1.2%. We found no significant difference in the rate of preterm delivery between pregnant individuals undergoing amniocentesis between 24 and 28 weeks and those between 28 and 32 weeks, reinforcing the procedure's safety across these gestational periods.

CONCLUSION

Late amniocentesis, at or after 24 weeks of gestation, especially for pregnancies complicated by multiple congenital anomalies, has a high diagnostic yield and a low complication rate, underscoring its clinical utility. It provides pregnant individuals and their providers with a comprehensive diagnostic evaluation and results before delivery, enabling informed counseling and optimized perinatal and neonatal care planning.

Is Amniocentesis after CVS Risky?

OBJECTIVE

Approximately, 2% of women who undergo chorionic villi sampling (CVS) will subsequently undergo amniocentesis due to placental mosaicism or sampling/laboratory issues. Our objective was to compare obstetric outcomes in women who underwent both procedures with those who had CVS alone.

STUDY DESIGN

Retrospective case-control study of patients with singleton pregnancies undergoing invasive testing from 2010 to 2020 was performed. All women who underwent CVS followed by amniocentesis were compared with a control group who underwent CVS alone matched (2:1) for age and year of pregnancy. Women with pregnancy loss at <16 weeks were excluded from the control group. Pregnancies terminated for genetic abnormalities were excluded. Obstetric outcomes were compared between cases and controls. Student t-test and Fisher's exact test were used for statistical comparison.

RESULTS

During the study period 2,539 women underwent CVS, and 66 (2.6%) subsequently underwent amniocentesis. The 66 cases were compared with 132 age-matched controls who underwent CVS alone. Mean maternal age was 36.8 ± 3.4 years, and 43% of women were nulliparous. Amniocentesis was performed due to sampling or laboratory issues in 33% of cases, placental mosaicism in 44%, and further diagnostic testing in 23%. There were no pregnancy losses or stillbirths in either group. Those who had two invasive procedures delivered at similar gestational ages and birthweights and did not have higher rates of adverse outcomes compared with those who underwent CVS alone.

CONCLUSION

Patients considering CVS who are concerned about the possibility that a second invasive procedure could be required should be reassured that this does not appear to be associated with higher rates of adverse outcomes. Due to study size, we cannot exclude the possibility of small differences in uncommon outcomes, such as pregnancy loss or stillbirth.

KEY POINTS

· Amniocentesis may be recommended after CVS due to mosaicism, sampling issues, or further testing.. · Amniocentesis after CVS is not associated with pregnancy loss or other adverse outcomes compared.. · Patients who have both CVS and amniocentesis deliver at similar gestational ages and birthweights..

Prenatal delivery of a therapeutic antisense oligonucleotide achieves broad biodistribution in the brain and ameliorates Angelman syndrome phenotype in mice

Angelman syndrome (AS), an early-onset neurodevelopmental disorder characterized by abnormal gait, intellectual disabilities, and seizures, occurs when the maternal allele of the UBE3A gene is disrupted, since the paternal allele is silenced in neurons by the UBE3A antisense (UBE3A-AS) transcript. Given the importance of early treatment, we hypothesized that prenatal delivery of an antisense oligonucleotide (ASO) would downregulate the murine Ube3a-AS, resulting in increased UBE3A protein and functional rescue. Using a mouse model with a Ube3a-YFP allele that reports on-target ASO activity, we found that in utero, intracranial (IC) injection of the ASO resulted in dose-dependent activation of paternal Ube3a, with broad biodistribution. Accordingly, in utero injection of the ASO in a mouse model of AS also resulted in successful restoration of UBE3A and phenotypic improvements in treated mice on the accelerating rotarod and fear conditioning. Strikingly, even intra-amniotic (IA) injection resulted in systemic biodistribution and high levels of UBE3A reactivation throughout the brain. These findings offer a novel strategy for early treatment of AS using an ASO, with two potential routes of administration in the prenatal window. Beyond AS, successful delivery of a therapeutic ASO into neurons has implications for a clinically feasible prenatal treatment for numerous neurodevelopmental disorders.

Assessing Recommendations for Determining Fetal Risk in Alloimmunized Pregnancies in the United States: Is It Time to Update a Decades-Old Practice?

The current recommended testing algorithm for assessing the alloimmunized pregnancy utilized by many obstetricians in the United States (US) fails to consider the most recent evidence, placing fetuses, and mothers at unnecessary risk of poor outcome or death. This narrative review of the current landscape of fetal red blood cell (RBC) antigen testing evaluates the history of hemolytic disease of the fetus and newborn (HDFN) and how its discovery has continued to influence practices in the US today. We compare current US-based HDFN practice guidelines with those in Europe. We also provide transfusion medicine and hematology perspectives and recommendations addressing the limitations of US practice, particularly regarding paternal RBC antigen testing, and discuss the most valuable alternatives based on decades of data and evidence-based recommendations from Europe.

Effect of cannula insertion site during fetal endoscopic tracheal occlusion for congenital diaphragmatic hernia on preterm prelabor rupture of membranes

OBJECTIVE

To assess whether the cannula insertion site on the maternal abdomen during fetal endoscopic tracheal occlusion (FETO) for congenital diaphragmatic hernia (CDH) was associated with preterm prelabor rupture of membranes (PPROM) before balloon removal.

METHODS

This was a multicenter retrospective study of consecutive pregnancies with isolated left- or right-sided CDH that underwent FETO in four centers between January 2009 and January 2021. The site for balloon insertion was categorized as above or below the umbilicus. One propensity score was analyzed in both groups to calculate an average treatment effect (ATE) by inverse probability of treatment weighting. Logistic regression and Cox proportional hazard regression including the ATE weights were performed to examine the effect size of entry point on the frequency and timing of PPROM before balloon removal.

RESULTS

A total of 294 patients were included. The mean ± SD gestational age at PPROM was 33.45 ± 2.01 weeks and the mean rate of PPROM before balloon removal was 25.9% (76/294). Gestational age at FETO was later in the below-umbilicus group (mean ± SD, 29.47 ± 1.29 weeks vs 29.00 ± 1.25 weeks; P = 0.002) and the duration of FETO was longer in the above-umbilicus group (median, 14.49 min (interquartile range (IQR), 8.00-21.00 min) vs 11.00 min (IQR, 7.00-14.49 min); P = 0.002). After balancing for possible confounding factors, trocar entry point below the umbilicus did not increase the risk of PPROM before balloon removal (adjusted odds ratio, 1.56 (95% CI, 0.89-2.74); P = 0.120) and had no effect on the timing of PPROM before balloon removal (adjusted hazard ratio, 1.56 (95% CI, 0.95-2.55); P = 0.080).

CONCLUSION

There was no evidence that uterine entry site for FETO was correlated with the risk of PPROM before balloon removal. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Congenital anomalies of the kidney and urinary tract: antenatal diagnosis, management and counselling of families

Congenital anomalies of the kidney and urinary tract are collectively one of the most commonly diagnosed antenatal conditions. Clinicians have several tools available to diagnose anomalies, including imaging, biomarkers, family history and genetic studies. In certain cases, antenatal interventions such as vesico-amniotic shunting may be considered to improve postnatal outcomes.Congenital kidney anomalies detected antenatally can vary in clinical significance from almost no impact postnatally to significant morbidity and perinatal mortality. Prognosis broadly depends on kidney size, structure and amount of amniotic fluid, alongside genetics and family history, and progression on subsequent scans. It is important to counsel parents appropriately using a parent-focused and personalised approach. The use of a multidisciplinary team should always be considered.

Chromosome balanced translocation in newborn fetus founded during prenatal diagnosis: Three cases reports

RATIONALE

Because of the normal phenotype, carriers of specific chromosomal translocations are often diagnosed only after their development of associated malignancies, recurrent miscarriages, and reproductive difficulties. In this paper, we report primary balanced fetal chromosomal translocations by performing the necessary invasive prenatal diagnosis in couples with previous malformations coupled with prenatal testing suggesting a high risk for trisomy 21.

PATIENT CONCERNS

Case 1 and Case 2 couples had malformed children, and Case 3 couples had a high risk of trisomy 21 on noninvasive preconception serological testing.

DIAGNOSIS AND INTERVENTION

A balanced chromosomal translocation diagnosis was confirmed by karyotyping of fetal cells obtained by amniocentesis.

OUTCOMES

All 3 couples decided to continue their pregnancies after learning about the consequences of the chromosomal abnormalities. Approximately a year after the children were born, the staff of the Prenatal Diagnostic Center followed up with a phone call and found that the children physical development and intelligence were normal.

LESSON

This case report reports healthy chromosomal balanced translocation newborns born to couples with poor maternal history and couples with abnormalities suggested by preconception testing, and followed up with the newborns to provide some experience in prenatal diagnosis and genetic counseling for chromosomal balanced translocations.

Noninvasive single-cell-based prenatal genetic testing: A proof of concept clinical study

OBJECTIVE

To clinically assess a cell-based noninvasive prenatal genetic test using sequence-based copy number analysis of single trophoblasts from maternal blood.

METHODS

Blood was obtained from 401 (243 + 158) individuals (8-22 weeks) and shipped overnight. Red cells were lysed, and nucleated cells stained for cytokeratin (CK) and CD45 and enriched for positive CK staining. Automated scanning was used to identify and pick single CK+ /CD45- trophoblasts which were subjected to next-generation sequencing.

RESULTS

Blood was obtained from 243 pregnancies scheduled for CVS or amniocentesis. Luna results were normal for 160 singletons while 15 cases were abnormal (14 aneuploidy and one monozygotic twin with Williams syndrome deletion). The deletion was confirmed in both fetuses. Placental mosaicism occurred in 7 of 236 (3.0%) Luna cases and in 3 of 188 (1.6%) CVS cases (total 4.6%). No scorable trophoblasts were recovered in 32 of 236 usable samples. Additionally, 158 low-risk pregnancies not undergoing CVS/amniocentesis showed normal results in 133 cases. Seven had aneuploidy results, and there were three likely pathogenic deletions/duplications, including one15q11-q13 deletion.

CONCLUSION

Although the sample size is modest and statistically accurate measures of test performance are not possible, the Luna test detected aneuploidy and deletions/duplications based on concordance with CVS/amniocentesis.

How I diagnose and treat antiphospholipid syndrome in pregnancy

ABSTRACT

Antiphospholipid syndrome (APS) is a rare autoimmune disease characterized by arterial, venous, or microvascular thrombosis, pregnancy morbidities, or nonthrombotic manifestations in patients with persistently positive antiphospholipid antibodies. These antibodies bind cellular phospholipids and phospholipid-protein complexes resulting in cellular activation and inflammation that lead to the clinical features of APS. Our evolving understanding of APS has resulted in more specific classification criteria. Patients meeting these criteria should be treated during pregnancy according to current guidelines. Yet, despite treatment, those positive for lupus anticoagulant have at least a 30% likelihood of adverse pregnancy outcomes. Patients with recurrent early miscarriage or fetal death in the absence of preeclampsia or placental insufficiency may not meet current classification criteria for APS. Patients with only low titer anticardiolipin or anti-β(2)-glycoprotein I antibodies or immunoglobulin M isotype antibodies will not meet current classification criteria. In such cases, clinicians should implement management plans that balance potential risks and benefits, some of which involve emotional concerns surrounding the patient's reproductive future. Finally, APS may present in pregnancy or postpartum as a thrombotic microangiopathy, a life-threatening condition that may initially mimic preeclampsia with severe features but requires a very different treatment approach.

State of the Science and Ethical Considerations for Preimplantation Genetic Testing for Monogenic Cystic Kidney Diseases and Ciliopathies

There is a broad phenotypic spectrum of monogenic polycystic kidney diseases (PKDs). These disorders often involve cilia-related genes and lead to the development of fluid-filled cysts and eventual kidney function decline and failure. Preimplantation genetic testing for monogenic (PGT-M) disorders has moved into the clinical realm. It allows prospective parents to avoid passing on heritable diseases to their children, including monogenic PKD. The PGT-M process involves embryo generation through in vitro fertilization, with subsequent testing of embryos and selective transfer of those that do not harbor the specific disease-causing variant(s). There is a growing body of literature supporting the success of PGT-M for autosomal-dominant and autosomal-recessive PKD, although with important technical limitations in some cases. This technology can be applied to many other types of monogenic PKD and ciliopathies despite the lack of existing reports in the literature. PGT-M for monogenic PKD, like other forms of assisted reproductive technology, raises important ethical questions. When considering PGT-M for kidney diseases, as well as the potential to avoid disease in future generations, there are regulatory and ethical considerations. These include limited government regulation and unstandardized consent processes, potential technical errors, high cost and equity concerns, risks associated with pregnancy for mothers with kidney disease, and the impact on all involved in the process, including the children who were made possible with this technology.

Residual risk of clinically significant copy number variations in fetuses with nasal bone absence or hypoplasia after excluding non-invasive prenatal screening-detectable findings

BACKGROUND

It remains controversial whether prenatal screening or diagnostic testing should be offered to fetuses with nasal bone (NB) absence or hypoplasia, and there are no studies comparing the yield of chromosomal microarray analysis (CMA) to non-invasive prenatal screening (NIPS). The aim of this study was to evaluate the residual risk of clinically significant copy number variations (CNVs) in fetuses with NB absence or hypoplasia after excluding theoretically NIPS-detectable abnormalities, and to assess their clinical outcomes.

METHODS

This prospective study encompassed 400 fetuses with NB absence or hypoplasia undergoing CMA testing between 2015 and 2022. Clinically significant CMA findings were categorized into three subgroups, including three-NIPS-detectable (trisomies 21, 18 and 13), five-NIPS-detectable (trisomies 21, 18 and 13 and sex chromosome aneuploidies) and genome-wide NIPS-detectable (variants over 7 Mb). We calculated the theoretical residual risk and compared it with the results of a control cohort of low-risk pregnancies. We further evaluated their clinical outcomes.

RESULTS

The overall diagnostic yield in our cohort was 7.8% (31/400). The detection rate of clinically significant CMA findings in fetuses with non-isolated NB absence or hypoplasia was significantly higher than that in fetuses with isolated NB absence or hypoplasia (20.0% vs. 6.6%, P =.005). The theoretical residual risks in all NIPS models were significantly higher when compared with the control cohort. The normal infant rate in fetuses with normal CMA results was 97.9% (323/330), and a significant higher incidence was observed in fetuses with isolated NB absence or hypoplasia compared with non-isolated NB absence or hypoplasia (98.4% vs. 91.7%, P =.028).

CONCLUSIONS

The residual risk of clinically significant CNVs in fetuses with NB absence or hypoplasia following the exclusion of theoretically NIPS-detectable findings was higher than that in low-risk pregnancies. This risk should be considered in genetic counseling to make a more comprehensive and precise choice regarding prenatal genetic testing.

Exploring factors impacting haplotype-based noninvasive prenatal diagnosis for single-gene recessive disorders

Haplotype-based noninvasive prenatal diagnosis (NIPD) is applicable for various recessive single-gene disorders in proband families. However, a comprehensive exploration of critical factors influencing the assay performance, such as fetal fraction, informative single nucleotide polymorphism (SNP) count, and recombination events, has yet to be performed. It is critical to identify key factors affecting NIPD performance, including its accuracy and success rate, and their impact on clinical diagnostics to guide clinical practice. We conducted a prospective study, recruiting 219 proband families with singleton pregnancies at risk for eight recessive single-gene disorders (Duchenne muscular dystrophy, spinal muscular atrophy, phenylketonuria, methylmalonic acidemia, hemophilia A, hemophilia B, non-syndromic hearing loss, and congenital adrenal hyperplasia) at 7-14 weeks of gestation. Haplotype-based NIPD was performed by evaluating the relative haplotype dosage (RHDO) in maternal circulation, and the results were validated via invasive prenatal diagnosis or newborn follow-ups. Among the 219 families, the median gestational age at first blood draw was 8+5 weeks. Initial testing succeeded for 190 families and failed for 29 due to low fetal fraction (16), insufficient informative SNPs (9), and homologous recombination near pathogenic variation (4). Among low fetal fraction families, successful testing was achieved for 11 cases after a redraw, while 5 remained inconclusive. Test failures linked to insufficient informative SNPs correlated with linkage disequilibrium near the genes, with F8 and MMUT exhibiting the highest associated failure rates (14.3% and 25%, respectively). Homologous recombination was relatively frequent around the DMD and SMN1 genes (8.8% and 4.8%, respectively) but led to detection failure in only 44.4% (4/9) of such cases. All NIPD results from the 201 successful families were consistent with invasive diagnostic findings or newborn follow-up. Fetal fraction, informative SNPs count, and homologous recombination are pivotal to NIPD performance. Redrawing blood effectively improves the success rate for low fetal fraction samples. However, informative SNPs count and homologous recombination rates vary significantly across genes, necessitating careful consideration in clinical practice. We have designed an in silico method based on linkage disequilibrium data to predict the number of informative SNPs. This can identify genomic regions where there might be an insufficient number of SNPs, thereby guiding panel design. With these factors properly accounted for, NIPD is highly accurate and reliable.

A cost-effectiveness analysis of pre-pregnancy genetic screening for deafness: an empirical study in China

Objectives

This research aims to assess the effectiveness and cost-effectiveness of pre-pregnancy deafness screening policies.

Methods

Married couples from Shanghai, Beijing, and Suzhou in China were enrolled. We conducted high-throughput, pre-pregnancy genetic screenings for deafness in women and their partners. We compared the cost-effectiveness of deafness genetic screening with the status quo. The two-step screening (wife then partner) and following treatments and interventions were included in the decision tree model. We conducted a cost-effectiveness analysis based on the decrease in deaf newborns, healthy newborn births, and cost-utility analysis of pre-pregnancy deafness genetic screening separately. Cost, utility, and probability data used in the three models were collected from a survey combined with literature and expert consultants. A 5% discount rate and a series of one-way sensitivity analyses along with a Monte Carlo simulation were used to test the reliability of this research.

Results

Between Jan 1, 2019, and Dec 31, 2021, we recruited 6,200 females and 540 male spouses from community health service centers in Shanghai, Beijing, and Suzhou. The incremental cost-effectiveness ratio (ICER) for reducing deaf newborn births was USD 32,656 per case and USD 1,203,926 per case for increasing one healthy newborn birth. This gap exists because of the overall decrease of newborn births. From the perspective of the whole society, deafness genetic screening is not cost-effective for reducing the overall quality-adjusted life years (QALY) in the population.

Discussion

Pre-pregnancy genetic testing is effective in decreasing the occurrence of congenital deafness. It is a cost-saving measure when compared with the costs of future medical expenditure and income loss for the affected families. However, such screening and preventive avoidance of pregnancy will decrease the population size and QALY. Only post-screening ART with PGT was shown to increase the birth of healthy newborns. Focusing on key groups such as premature births or consanguineous couples may improve the societal effects of screening.

Prevalence of high-penetrant copy number variants in 7734 low-risk pregnancies

BACKGROUND

The rate of clinically significant copy number variants in chromosomal microarray analysis in low-risk pregnancies is approximately 1%. However, these results include copy number variants with low and variable penetrance, although some patients might be interested only in the detection of high-penetrant variants.

OBJECTIVE

This study aimed to calculate the prevalence of high-penetrant copy number variants in a large cohort of low-risk pregnancies.

STUDY DESIGN

This retrospective study was performed using microarray results of pregnancies with normal ultrasound and maternal serum screening. All clinically significant (pathogenic and likely pathogenic) copy number variants were recorded. Of these, only high-penetrant findings were selected. Findings with low and medium penetrance and copy number variants with unknown clinical penetrance, including uniparental disomy of segments not related to known imprinted syndromes, mosaic aneuploidy of <50%, and segmental mosaicism, were excluded. The calculation was performed for the overall cohort, for women aged >35 years and women aged <35 years, and after omission of noninvasive prenatal screening theoretically detectable findings (trisomies 13, 18, and 21).

RESULTS

Clinically significant copy number variants were detected in 118 of 7734 cases (1.50% or 1:65), and high-penetrant copy number variants were detected in 33 of 7734 cases (0.43% or 1:234). In women aged ≥35 years, the rates of high-penetrant copy number variants were 29 of 5734 cases (0.51% or 1:198) and 4 of 2000 cases (0.20% or 1:500) in women aged <35 years (P=.0747). Following the omission of 12 theoretically noninvasive prenatal screening-detectable findings, the rates of high-penetrant copy number variants declined to 21 of 7722 cases (0.27% or 1:368) in the whole cohort-18 of 5723 cases (0.31% or 1:318) in woman aged ≥35 years and 3 of 1999 cases (0.15% or 1:666) in younger women (P=.319).

CONCLUSION

The risk of high-penetrant copy number variants in low-risk pregnancies exceeds the risk of miscarriage after invasive testing, even after normal noninvasive prenatal screening results. These results are of importance to genetic counselors and obstetricians, to facilitate maternal informed decision-making when considering invasive prenatal testing in low-risk pregnancies.

Toxoplasma gondii Infection in Pregnancy - Recommendations of the Working Group on Obstetrics and Prenatal Medicine (AGG - Section on Maternal Disorders)

Aim The AGG (Working Group for Obstetrics and Prenatal Diagnostics, Section Maternal Diseases) has issued these recommendations to improve the detection and management of Toxoplasma gondii infection in pregnancy. Methods Members of the Task Force developed the recommendations and statements presented here using recently published literature. The recommendations were adopted after a consensus process by members of the working group. Recommendations This article focuses on the epidemiology and pathophysiology of Toxoplasma gondii infection in pregnancy and includes recommendations for maternal and fetal diagnosis, transmission prophylaxis, therapy, prevention, screening, and peripartum management.

Bringing precision medicine to the management of pregnancy in women with glucokinase-MODY: a study of diagnostic accuracy and feasibility of non-invasive prenatal testing

AIMS/HYPOTHESIS

In pregnancies where the mother has glucokinase-MODY (GCK-MODY), fetal growth is determined by fetal genotype. When the fetus inherits a maternal pathogenic GCK variant, normal fetal growth is anticipated, and insulin treatment of maternal hyperglycaemia is not recommended. At present, fetal genotype is estimated from measurement of fetal abdominal circumference on ultrasound. Non-invasive prenatal testing of fetal GCK genotype (NIPT-GCK) using cell-free DNA in maternal blood has recently been developed. We aimed to compare the diagnostic accuracy of NIPT-GCK with that of ultrasound, and determine the feasibility of using NIPT-GCK to guide pregnancy management.

METHODS

We studied an international cohort of pregnant women with hyperglycaemia due to GCK-MODY. We compared the diagnostic accuracy of NIPT-GCK with that of measurement of fetal abdominal circumference at 28 weeks' gestation (n=38) using a directly genotyped offspring sample as the reference standard. In a feasibility study, we assessed the time to result given to clinicians in 43 consecutive pregnancies affected by GCK-MODY between July 2019 and September 2021.

RESULTS

In terms of diagnostic accuracy, NIPT-GCK was more sensitive and specific than ultrasound in predicting fetal genotype (sensitivity 100% and specificity 96% for NIPT-GCK vs sensitivity 53% and specificity 61% for fetal abdominal circumference 75th percentile). In terms of feasibility, a valid NIPT-GCK fetal genotype (≥95% probability) was reported in all 38 pregnancies with an amenable variant and repeated samples when needed. The median time to report was 5 weeks (IQR 3-8 weeks). For the 25 samples received before 20 weeks' gestation, results were reported at a median gestational age of 20 weeks (IQR 18-24), with 23/25 (92%) reported before 28 weeks.

CONCLUSIONS/INTERPRETATION

Non-invasive prenatal testing of fetal genotype in GCK-MODY pregnancies is highly accurate and is capable of providing a result before the last trimester for most patients. This means that non-invasive prenatal testing of fetal genotype is the optimal approach to management of GCK-MODY pregnancies.

Chorioamnionitis: An Update on Diagnostic Evaluation

Chorioamnionitis remains a major cause of preterm birth and maternal and neonatal morbidity. We reviewed the current evidence for the diagnostic tests of chorioamnionitis and how this relates to clinical practice today. A comprehensive literature search and review was conducted on chorioamnionitis and intra-uterine inflammation. Data from randomized control trials and systematic reviews were prioritized. This review highlights that sterile inflammation plays an important role in chorioamnionitis and that the current tests for chorioamnionitis including clinical criteria, maternal plasma and vaginal biomarkers lack diagnostic accuracy. Concerningly, these tests often rely on detecting an inflammatory response after damage has occurred to the fetus. Care should be taken when interpreting current investigations for the diagnosis of chorioamnionitis and how they guide obstetric/neonatal management. There is an urgent need for further validation of current diagnostic tests and the development of novel, accurate, minimally invasive tests that detect subclinical intra-uterine inflammation.

Identification of Fetuses at Increased Risk of Trisomies in the First Trimester Using Axial Planes

INTRODUCTION

The measurement of nuchal translucency (NT) is crucial for assessing risk of aneuploidies in the first trimester. We investigate the ability of NT assessed by a transverse view of the fetal head to detect fetuses at increased risk of common aneuploidies at 11-13 weeks of gestation.

METHODS

We enrolled a nonconsecutive series of women who attended our outpatient clinic from January 2020 to April 2021 for aneuploidy screening by means of a first trimester combined test. All women were examined by operators certified by the Fetal Medicine Foundation. In each patient, NT measurements were obtained both from the median sagittal view and transverse view. We calculated the risk of aneuploidy using NT measurements obtained both with sagittal and axial scans, and then we compared the results.

RESULTS

A total of 1,023 women were enrolled. An excellent correlation was found between sagittal and transverse NT measurements. The sensitivity and specificity of the axial scan to identify fetuses that were deemed at risk of trisomy 21 using standard sagittal scans were 40/40 = 100.0% (95% confidence interval [CI]: 91.2-100.0) and 977/983 = 99.4% (95% CI: 98.7-99.7), respectively. The sensitivity and specificity of the axial scan to identify fetuses at risk of trisomy 13 or 18 were 16/16 = 100.0% (95% CI: 80.6-100.0) and 1,005/1,007 = 99.8% (95% CI: 99.3-99.9).

CONCLUSIONS

When the sonogram, a part of combined test screening, is performed by an expert sonologist, axial views can reliably identify fetuses at increased risk of trisomies without an increase in false negative results.

Obstetrical outcomes following amniocentesis performed after 24 weeks of gestation: A systematic review and meta-analysis

To evaluate obstetrical outcomes for women having late amniocentesis (on or after 24 weeks). Electronic databases were searched from inception to January 1st, 2023. The obstetrical outcomes evaluated were gestational age at delivery, preterm birth (PTB) < 37 weeks, PTB within 1 week from amniocentesis, premature prelabor rupture of membranes (pPROM), chorionamnionitis, placental abruption, intrauterine fetal demise (IUFD) and termination of pregnancy (TOP). The incidence of PTB <37 weeks was 4.85% (95% CI 3.48-6.56), while the incidence of PTB within 1 week was 1.42% (95% CI 0.66-2.45). The rate of pPROM was 2.85% (95% CI 1.21-3.32). The incidence of placental abruption was 0.91% (95% CI 0.16-2.25), while the rate of IUFD was 3.66% (95% CI 0.00-14.04). The rate of women who underwent TOP was 6.37% (95%CI 1.05-15.72). When comparing amniocentesis performed before or after 32 weeks, the incidence of PTB within 1 week was 1.48% (95% CI 0.42-3.19) and 2.38% (95% CI 0.40-5.95). Amniocentesis performed late after 24 weeks of gestation is an acceptable option for patients needing prenatal diagnosis in later gestation.

[Towards a generalization of non-invasive prenatal diagnosis of single-gene disorders? Assesment and outlook]

OBJECTIVES

The screening of fetal aneuploidies and non-invasive prenatal diagnosis of monogenic diseases (NIPD-MD) both rely on the study of free fetal DNA in maternal circulation, but their respective rise was unequal. Development of NIPD-MD has taken longer as it represents a less attractive commercial dynamic for industry, but also because it usually involves the development of tailored tests specific to each pathogenic variant.

METHODS

We have carried out a review of the literature on the various indications and technologies involved in the use of NIPD-MM. We present its current implementation and its development in France.

RESULTS

To date, NIPD-MD has been routinely offered in France for several years by the laboratories of the French NIPD-MD network but remains mostly limited to the exclusion of paternal or de novo variants, the exclusion DPNI-MD. Indeed, it is still difficult to study the transmission of maternal variants from circulating free DNA analysis, due to its biological complexity: coexistence and predominance of similar DNA sequences of maternal origin. Different strategies, either direct or indirect, are being evaluated to establish fetal status regardless of the parental origin of the disease or its transmission mode. The emergence of commercial screening solutions for monogenic diseases complements the arsenal of prenatal exploration tools for these diseases.

CONCLUSION

The multitude of existing technologies and protocols may complicate the information provided during antenatal consultations, but mastery of know-how and knowledge of ethical issues of NIPD-MD will ensure optimal service and better management of pregnancies at risk of transmitting monogenic disease.

Clinical interpretation of cell-based non-invasive prenatal testing for monogenic disorders including repeat expansion disorders: potentials and pitfalls

Introduction: Circulating fetal cells isolated from maternal blood can be used for prenatal testing, representing a safe alternative to invasive testing. The present study investigated the potential of cell-based noninvasive prenatal testing (NIPT) for diagnosing monogenic disorders dependent on the mode of inheritance. Methods: Maternal blood samples were collected from women opting for prenatal diagnostics for specific monogenic disorders (N = 7). Fetal trophoblasts were enriched and stained using magnetic activated cell sorting and isolated by fluorescens activated single-cell sorting. Individual cells were subject to whole genome amplification, and cells of fetal origin were identified by DNA-profiling using short tandem repeat markers. The amplified fetal DNA was input for genetic testing for autosomal dominant-, autosomal recessive-, X-linked and repeat expansion disorders by direct variant analysis and haplotyping. The cell-based NIPT results were compared with those of invasive testing. Results: In two cases at risk of skeletal dysplasia, caused by variants in the FGFR3 gene (autosomal dominant disorders), cell-based NIPT correctly stated an affected fetus, but allelic dropout of the normal alleles were observed in both cases. Cell-based NIPT gave an accurate result in two cases at risk of autosomal recessive disorders, where the parents carried either different diastrophic dysplasia causing variants in the SLC26A2 gene or the same cystic fibrosis disease-causing variant in the CFTR gene. Cell-based NIPT accurately identified an affected male fetus in a pregnancy at risk of Duchenne muscular dystrophy (DMD gene, X-linked recessive disorders). In two cases at risk of the myotonic dystrophy type 1 (DMPK gene, repeat expansion disorder), cell-based NIPT correctly detected an affected and an unaffected fetus, respectively. Discussion: Circulating fetal cells can be used to detect both maternally- and paternally inherited monogenic disorders irrespective of the type of variant, however, the risk of allelic dropout must be considered. We conclude that the clinical interpretation of the cell-based NIPT result thus varies depending on the disorders' mode of inheritance.

Severe maternal thrombocytopenia and prenatal invasive procedures: still a grey zone

Management of severe thrombocytopenia, particularly of ITP, in pregnancy is mainly based on expert consensus and clinical experience while there are no clear indications about the minimum platelet count requested for prenatal diagnosis invasive procedures. Since the lack of specific recommendations we reported our clinical management of a patient suffering from severe thrombocytopenia, undergoing amniocentesis. Due to the anecdotic possibility of maternal and fetal bleeding in case of severe thrombocytopenia, prophylaxis with IVIG or even corticosteroids could be considered as a safer strategy to prevent post-procedural adverse outcomes.

Application of non-invasive prenatal testing to 91,280 spontaneous pregnancies and 3477 pregnancies conceived by in vitro fertilization

BACKGROUND

Many clinical studies based on spontaneous pregnancies (SPs) have demonstrated the superiority of non-invasive prenatal testing (NIPT), and the question of whether this technology is suitable for offspring conceived by assisted reproductive technology has attracted attention. This study aimed to evaluate the application value of NIPT in screening for trisomy (T)21, T18, T13 and sex chromosome aneuploidy (SCA) in pregnant women who conceived by in vitro fertilization (IVF).

RESULTS

In total, there were 804 high-risk cases [0.88% (804/91280), singleton = 795, twin = 9] in the SP group. Among the 558 invasive prenatal diagnosis (IPD) cases (singleton = 556, twin = 2), 343 (singleton = 342, twin = 1) were true positive, including 213 cases of T21, 28 of T18, 5 of T13 and 97 (singleton = 96, twin = 1) of SCA. The positive predictive values (PPVs) of T21, T18, T13, SCA and T21/T18/T13 combined in singleton pregnancy were 89.12% (213/239), 51.85% (28/54), 21.74% (5/23), 40.00% (96/240), and 77.85% (246/316), respectively, and the PPV of SCA in twin pregnancy was 100.00%. In the IVF group, IPD was performed in 19 (singleton = 16, twin = 3) of the 27 high-risk cases [0.78% (27/3477), singleton = 16, twin = 3], of which 9 (singleton = 8, twin = 1) were true positive, including 5 cases (singleton = 4, twin = 1) of T21 and 4 of SCA. The PPVs of singleton T21, SCA and T21/T18/T13 combined were 66.67% (4/6), 50.00% (4/8) and 57.14% (4/7), respectively, and the PPV of twin T21 was 100.00% (1/1). There were no significant differences in PPV among T21, SCA and T21/T18/T13 combined in singletons between the groups (89.12% vs. 66.67%, p = 0.09; 40.00% vs. 50.00%, p = 0.57; 77.85% vs. 57.14%, p = 0.20). The sensitivity and specificity were higher for singleton and twin pregnancies in the two groups. Based on follow-up results, 1 case of false negative T21 was found in the singleton SP group. Additionally, the mean foetal fraction (FF) of the IVF group was lower than that of the SP group (11.23% vs. 10.51%, p < 0.05).

CONCLUSION

NIPT has high sensitivity and specificity in screening chromosomal aneuploidies in both IVF pregnancy and spontaneous pregnancy, so it is an ideal screening method for IVF pregnancy.

Prenatal diagnosis after high chance non-invasive prenatal testing for trisomies 21, 18 and 13, chorionic villus sampling or amniocentesis? - Experience at a district general hospital in the United Kingdom

The non-invasive prenatal testing (NIPT) analyses cell-free DNA (cfDNA) derived from the placental tissue in the maternal circulation. Though highly sensitive and specific, a major limitation is in cases of confined placental mosaicism (CPM). Whether to perform chorionic villus sampling (CVS) or amniocentesis to confirm a positive NIPT result is controversial. One major drawback of CVS is that cytogenetic diagnosis may not always reflect the true chromosomal make-up of the fetus. This work, therefore, proposes the use of amniocentesis in the presence of normal ultrasound findings, and the option of either CVS or amniocentesis when there are abnormal USS findings.

Non-invasive prenatal testing (NIPT): Combination of copy number variant and gene analyses using an "in-house" target enrichment next generation sequencing-Solution for non-centralized NIPT laboratory?

OBJECTIVE

Recent studies have integrated copy number variant (CNV) and gene analysis using target enrichment. Here, we transferred this concept to our routine genetics laboratory, which is not linked to centralized non-invasive prenatal testing (NIPT) facilities.

METHOD

From a cohort of 100 pregnant women, 22 were selected for the analysis of maternal genomic DNA (gDNA) along with fetal cell-free DNA. Using targeted enrichment, 135 genes were analyzed, combined with aberrations of chromosomes 21, 18, 13, X, and Y. The data were subjected to specificity and sensitivity analyses, and correlated with the results from invasive testing methods.

RESULTS

The sensitivity/specificity was determined for the CNV analysis of chromosomes: 21 (80%/75%), 18 (-/82%), 13 (100%/67%), and Y (100%/100%). The gene detection was valid for maternal gDNA. However, for cell-free fetal DNA, it was not possible to determine the boundary between an artifact and a real sequence variant.

CONCLUSION

The target enrichment method combining CNV and gene detection seems feasible in a regular laboratory. However, this method can only be responsibly optimized with a sufficient number of controls and further validation on a strong bioinformatic background. The present results showed that NIPT should be performed in specialized centers, and that its introduction to isolated laboratories may not provide valid data.

Creation of a novel synthetic amniotic fluid for use in fetal therapy with in vitro testing on human amniotic membranes

BACKGROUND

Normal saline or lactated Ringer's solutions are usually infused at the time of fetal interventions; however, the effect of these fluids on the amniotic membranes has never been assessed. Given both the significant differences between the composition of normal saline solution, lactated Ringer's solution, and amniotic fluid and the significant risk of prematurity after fetal interventions, an investigation is warranted.

OBJECTIVE

This study aimed to evaluate the effect of current amnioinfusion fluids on the human amnion compared with a novel synthetic amniotic fluid.

STUDY DESIGN

Amniotic epithelial cells from term placentas were isolated and cultured per protocol. A synthetic amniotic fluid was created with similar electrolyte, pH, albumin, and glucose concentrations to human amniotic fluid, termed "Amnio-well." The cultured human amniotic epithelium was exposed to normal saline solution, lactated Ringer's solution, and Amnio-well. As a control, 1 group of cells remained in culture media. Cells were evaluated for apoptosis and necrosis. A second analysis to examine if cells could be "rescued" was performed, wherein the cells were allowed to remain in the culture media for an additional 48 hours after amnioinfusion. Subsequently, tissue testing with human amniotic membrane explants was evaluated similarly. Immunofluorescent intensity studies were undertaken to evaluate reactive oxygen species-mediated cell damage. Real-time quantitative polymerase chain reaction was used to evaluate gene expression in apoptotic pathways.

RESULTS

With simulated amnioinfusion, 44%, 52%, and 89% of amniotic epithelial cells were alive after exposure to normal saline solution, lactated Ringer's solution, and Amnio-well, respectively, compared with 85% in control (P<.001). After amnioinfusion and attempted cell rescue, 21%, 44%, 94%, and 88% of cells were alive after exposure to normal saline solution, lactated Ringer's solution, Amnio-well, and control, respectively (P<.001). In simulated amnioinfusion with full-thickness tissue explants, 68%, 80%, 93%, and 96% of cells were viable in normal saline solution, lactated Ringer's solution, Amnio-well, and control, respectively (P<.001). In culture, reactive oxygen species production was higher in normal saline solution, lactated Ringer's solution, and Amnio-well than in control (4.9-, 6.6-, and 1.8-fold higher, respectively, P<.001); however, this could be mitigated in Amnio-well by adding ulin-A-statin and ascorbic acid. Gene expression data revealed abnormal signaling in the p21 and BCL2/BAX pathways with normal saline solution compared with control (P=.006 and P=.041); changes were not seen with Amnio-well.

CONCLUSION

In vitro, normal saline and lactated Ringer's solutions caused increased amniotic membrane reactive oxygen species and cell death. The use of a novel fluid similar to human amniotic fluid led to the normalization of cellular signaling and less cell death.

Cell-based Noninvasive Prenatal Testing (cbNIPT)-A Review on the Current Developments and Future Prospects

Considering the diagnostic limitations of cfDNA-based noninvasive prenatal testing (NIPT), scientists have long been interested in isolating and analyzing rare intact fetal and trophoblast cells from maternal blood or endocervical samples to diagnose fetal genetic conditions. These cells may be scarce and difficult to isolate, but they are a direct source of pure fetal genetic material. In this review, we summarize the history of cell-based NIPT, present an updated review on its current developments, evaluate its genetic diagnostic potential, and discuss its future prospects for clinical use.

Late amniocentesis: better late than never? A single referral centre experience

INTRODUCTION

Several congenital abnormalities present late in pregnancy necessitating invasive testing to rule out genetic/infectious causes at late gestation. Not many studies have described the indications/safety of a late gestation amniocentesis.

METHODS

All records of amniocentesis performed beyond 24 weeks were reviewed and evaluated for indications, positive yield and complications.

RESULTS

About 187 women had an amniocentesis after 24 weeks for various indications with CNS abnormalities being the commonest. The total yield of positive findings was 14.60% (22/150; excluding 2 VOUS). CNS, multiple system involvement and skeletal system anormalities yielded maximum results. About 32.05% abnormalities could have potentially been detected at the time of a routine anomaly scan. Amongst all the deliveries, 2.1%  delivered spontaneously within a week of the procedure and about 5.4% delivered spontaneously within a month of the procedure.

CONCLUSION

The study emphasises the need for additional accreditation (FMF, ISUOG) of sonographers to ensure the detection of anomalies at the routine 18-20 weeks scan. Inspite of a normal mid-trimester scan, central nervous system and gastrointestinal abnormalities presented more commonly after 24 weeks. The high positive yield in our study highlights the importance of testing even in late pregnancy beyond the legal age of termination. The test could clearly stratify the pregnancies with a poor outcome whilst reassuring the others. The procedure itself did not lead to a neonatal death due to prematurity.

Evaluation of noninvasive prenatal screening for copy number variations among screening laboratories

OBJECTIVE

To evaluate the current situation of expanded noninvasive prenatal screening (NIPS) for copy number variations (CNVs) in laboratories in China, the National Center of Clinical Laboratories conducted an externalqualityassessment (EQA) program.

METHODS

The EQA panel consisted of 12 artificial samples associated with different syndromes, which were mixed with maternal plasma collected from pregnant women and enzyme-digested cell-free DNA (cfDNA) from cell lines with different fetal fractions (FFs) ranging from 5% to 15%. The panel was validated by next-generation sequencing and distributed to laboratories, along with questionnaires and case scenarios.

RESULTS

Sixty-nine laboratories participated in the EQA program, and 91.30% (63/69) of laboratories correctly identified all samples. A total of 7.25% (5/69) of the laboratories reported false-negative results, and 2.90% (2/69) of the laboratories reported unexpected CNVs. The correct rates of the 22q11.2 deletion syndrome, Cri-du-chat syndrome, 1p36 deletion syndrome and Angelman/Prader-Willi syndrome samples were 97.46%, 98.55%, 100%, and 100%, respectively. With the increase in the FF, deletion size, and read depth, the detection rate increased. For results reports, only five laboratories reported FF values, one laboratory reported the CNV classification type, and none reported sensitivity, specificity, positive predictive values, and negative predictive values.

CONCLUSION

The detection capabilities of NIPS for CNVs still need to be improved and standardized, and FF, deletion size, and read depth are factors that affect the detection rate.

Intra-amniotic sildenafil treatment improves lung blood flow and pulmonary hypertension in congenital diaphragmatic hernia rats

Pulmonary hypertension associated with congenital diaphragmatic hernia (CDH) is a critical factor in determining prognosis. We propose that intra-amniotic sildenafil administration is an effective prenatal therapy for CDH-induced pulmonary hypertension. To assess the efficacy of this treatment, we administered sildenafil to nitrofen-induced congenital diaphragmatic hernia fetuses and control fetuses via an intra-amniotic injection after a laparotomy on the pregnant dam at either E13.5 or E15.5. Intra-amniotic sildenafil treatment attenuated peripheral vascular muscularization, enhanced pulmonary blood flow, and increased the ratio of pulmonary artery size to aortic size in congenital diaphragmatic hernia fetuses after both E13.5 and E15.5 treatments. E13.5-treated congenital diaphragmatic hernia fetuses showed a higher and more prolonged expression of cyclic guanosine monophosphate (cGMP)-dependent protein kinase and more production of vascular endothelial growth factor, resulting in a significant improvement in lung architecture. The E13.5-treated congenital diaphragmatic hernia fetuses also had an increase in lung weight-to-body weight ratio and an improved fetal survival. Intra-amniotic sildenafil treatment did not show any detectable negative effects in control fetuses. Intra-amniotic sildenafil treatment for rats attenuates CDH-induced pulmonary hypertension and enhanced peripheral pulmonary blood flow. Moreover, early intervention may be preferable to better accelerate lung development and improve prognosis. Direct sildenafil administration via an intra-amniotic injection may be a promising option in congenital diaphragmatic hernia prenatal therapy.

Laboratory performance of genome-wide cfDNA for copy number variants as compared to prenatal microarray

BACKGROUND

Noninvasive prenatal testing (NIPT) allows for screening of fetal aneuploidy and copy number variants (CNVs) from cell-free DNA (cfDNA) in maternal plasma. Professional societies have not yet embraced NIPT for fetal CNVs, citing a need for additional performance data. A clinically available genome-wide cfDNA test screens for fetal aneuploidy and CNVs larger than 7 megabases (Mb).

RESULTS

This study reviews 701 pregnancies with "high risk" indications for fetal aneuploidy which underwent both genome-wide cfDNA and prenatal microarray. For aneuploidies and CNVs considered 'in-scope' for the cfDNA test (CNVs ≥ 7 Mb and select microdeletions), sensitivity and specificity was 93.8% and 97.3% respectively, with positive and negative predictive values of 63.8% and 99.7% as compared to microarray. When including 'out-of-scope' CNVs on array as false negatives, the sensitivity of cfDNA falls to 48.3%. If only pathogenic out-of-scope CNVs are treated as false negatives, the sensitivity is 63.8%. Of the out-of-scope CNVs identified by array smaller than 7 Mb, 50% were classified as variants of uncertain significance (VUS), with an overall VUS rate in the study of 2.29%.

CONCLUSIONS

While microarray provides the most robust assessment of fetal CNVs, this study suggests that genome-wide cfDNA can reliably screen for large CNVs in a high-risk cohort. Informed consent and adequate pretest counseling are essential to ensuring patients understand the benefits and limitations of all prenatal testing and screening options.

Financial contribution as reason to opt out of non-invasive prenatal testing

OBJECTIVE

First trimester non-invasive prenatal testing (NIPT) provides pregnant women with a reliable, non-invasive method to screen for fetal aneuploidies. In the Netherlands, there is a nationwide prenatal screening program in which pregnant women and their partners are counseled about their options around 10 weeks of pregnancy. The first trimester and second trimester scan are fully reimbursed but the NIPT has an own financial contribution of €175 per participant, irrespective of type of insurance. The arguments for this own contribution are fear of uncritical use of NIPT or routinization. NIPT has a relatively stable uptake of 51%, against over 95% for second trimester anomaly scan. We aimed to explore the effect of this financial contribution on the decision to opt out of NIPT.

STUDY DESIGN

We performed a survey among 350 pregnant women undergoing a second trimester anomaly scan in our center, Amsterdam UMC, between January 2021 and April 2022. All pregnant women who declined NIPT in the first trimester, were asked to participate and answered 11-13 questions about the decision-making process, the reasons to opt out and the financial contribution.

RESULTS

Information about NIPT was desired in 92% of women and 96% felt sufficiently informed. Most women took the decision not to perform NIPT with their partner and did not experience difficulties in taking this decision. The most important reason to decline NIPT was: "Every child is welcome" (69%). "The test was too expensive" was answered in 12% and was significantly correlated with lower maternal age. Additionally, one in five women (19%) said they would have done NIPT if it had been for free, which was significantly higher in younger women.

CONCLUSIONS

The own financial contribution plays a role in the decision-making to decline NIPT and partly explains the low uptake in the Netherlands. This suggests that there is no equal access to fetal aneuploidy screening. To overcome this inequality, this own contribution should be abandoned. We speculate that this will have a positive effect on the uptake, which will increase to at least 70% and potentially 94%.

"Overestimated technology - underestimated consequences" - reflections on risks, ethical conflicts, and social disparities in the handling of non-invasive prenatal tests (NIPTs)

New technologies create new complexities. Since non-invasive prenatal tests (NIPTs) were first introduced, keeping pace with complexity constitutes an ongoing task for medical societies, politics, and practice. NIPTs analyse the chromosomes of the fetus from a small blood sample. Initially, NIPTs were targeted at detecting trisomy 21 (Down syndrome): meanwhile there are sequencing techniques capable of analysing the entire genome of the unborn child. These yield findings of unclear relevance for the child's future life, resulting in new responsibility structures and dilemmas for the parents-to-be.The industry's marketing strategies overemphasize the benefits of the tests while disregarding their consequences. This paper chooses the opposite path: starting with the underestimated consequences, it focuses on adverse developments and downsides. Disparities, paradoxes, and risks associated with NIPTs are illustrated, ethical conflicts described. Indications that new technologies developed to solve problems create new ones are examined. In the sense of critical thinking, seemingly robust knowledge is scrutinized for uncertainties and ambiguities. It analyses how the interplay between genetic knowledge and social discourse results in new dimensions of responsibility not only for parents-to-be, but also for decision-makers, authorities, and professional societies, illustrated by a review of different national policies and implementation programmes. As shown by the new NIPT policy in Norway, the consequences can be startling. Finally, a lawsuit in the United States illustrates how an agency can risk forfeiting its legitimation in connection with the inaccuracy of NIPTs.

DEGUM Recommendations on Diagnostic Puncture in Prenatal Medicine

Diagnostic puncture (amniocentesis, chorionic villus sampling, and fetal blood sampling) is an essential part of prenatal diagnostics and the only established and sufficiently scientifically evaluated possibility of diagnosing genetic diseases from pregnancy-specific cells. The number of diagnostic punctures in Germany, as in other countries, has fallen significantly. This is largely due to the introduction of first-trimester screening with further detailed ultrasound examination of the fetus and the analysis of cf-DNA (cell-free DNA) from maternal blood (noninvasive prenatal test - NIPT). On the other hand, knowledge about the incidence and appearance of genetic diseases has increased. The development of modern molecular genetic techniques (microarray and exome analysis) makes a differentiated investigation of these diseases increasingly possible. The requirements for education and counseling regarding these complex correlations have thus increased. The studies performed in recent years make it clear that diagnostic puncture performed in expert centers is associated with a low risk of complications. In particular, the procedure-related miscarriage risk hardly differs from the background risk for spontaneous abortion. In 2013, the Section of Gynecology and Obstetrics of the German Society for Ultrasound in Medicine (DEGUM) published recommendations on diagnostic puncture in prenatal medicine 1. The developments described above and new findings in recent years make it necessary to revise and reformulate these recommendations. The aim of this review is to compile important and current facts regarding prenatal medical puncture (including technique, complications, genetic examinations). It is intended to provide basic, comprehensive, and up-to-date information on diagnostic puncture in prenatal medicine. It replaces the publication from 2013 1.

Evaluation of Fetal and Maternal Outcomes in Chorion Villus Sampling (CVS)

Background

Chorionic villus sampling (CVS) is one of the invasive diagnostic methods used to diagnose chromosomal, genetic, and metabolic diseases in the embryonic period. The use of this method is associated with maternal and fetal consequences, the most serious of which is abortion. Therefore, the present study was conducted to investigate the incidence of these consequences and the factors affecting the incidence of abortion.

Materials and Methods

A cross-sectional study was performed on 98 pregnant women with CVS indications. Maternal and fetal outcomes including abortion, vaginal bleeding, subchorionic hematoma, premature rupture of membrane (PROM), chorioamnionitis, preterm delivery, limb abnormality, fetal growth retardation, and preeclampsia were recorded.

Results

The results of the present study showed that the incidence of fetal outcomes including fetal growth failure, premature rupture of membranes, abortion, and limb abnormalities was 4.1%, 7.1%, 3.1%, and 1%, and the incidence of maternal outcomes including preterm delivery, subchorionic hematoma, preeclampsia, and hemorrhage was 14.3%, 3.1%, 6.1%, and 10.2%, respectively. In addition, a decrease in free BHCG and an increase in NT were significantly associated with the occurrence of abortion (OR: 0.11 and 4.25, respectively, P value < 0.05).

Conclusion

It should be noted that due to a long time between placental sampling and the occurrence of vaginal bleeding, premature rupture of membrane, and preterm delivery, it seems that placental sampling has no effect. In addition, only a decrease in free BHCG or an increase in NT significantly increased the chance of miscarriage.