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

The path winds along isolation and analyses of fetal nucleated red blood cells in maternal peripheral blood: Past, present, and future toward non-invasive prenatal diagnosis

Traditional prenatal diagnosis detects fetal disorders through invading uterus to access fetal cells, which may cause maternal complications, fetal injury, or even miscarriage. Safe and convenient non-invasive prenatal testing (NIPT) by analyzing fetal materials (cell-free DNA/RNA, cells, and extracellular vesicles) that circulate in maternal peripheral blood attracts great attention and has been applied in risk evaluation of several fetal disorders. Among those fetal analytes, fetal nucleated red blood cells (fNRBCs) comprise entire fetal genome, possess distinct membrane antigens, and have a lifespan limited in every single gestation. They were once expected to be an ideal biomarker for NIPT and even definitive prenatal diagnosis. However, recent advances of fNRBC-based NIPT are limited and their applications toward clinical practices are still challenging. Herein, we comprehensively overview research on fNRBCs in maternal peripheral blood, trying to dissect current predicament and inspire potential solutions. The source and lineage of fNRBCs, their entrance into maternal peripheral blood, and their physiochemical characteristics are discussed, and various strategies of label-free or immuno-affinitive isolation and subsequential identification of fNRBCs from maternal blood cells are summarized. Although proof-of-concept analyses toward detecting a few fetal disorders are demonstrated, current fNRBC-based NIPT still suffers many challenges when applied to clinical practices. Nevertheless, via thorough investigation and new analytical technologies, it is believed fNRBC-based NIPT will provide a promising platform to supplement the insufficiency of current strategies.

Intra-amniotic antisense oligonucleotide treatment improves phenotypes in preclinical models of spinal muscular atrophy

Neurological disorders with onset before or at birth are a leading cause of morbidity and mortality in infants and children. Prenatal treatment has the potential to reduce or prevent irreversible neuronal loss and facilitate normal neurodevelopment. We hypothesized that antisense oligonucleotides (ASOs) delivered to the amniotic fluid by intra-amniotic (IA) injection could safely distribute to the fetal central nervous system (CNS) and provide therapeutic benefit in the motor neuron disease spinal muscular atrophy (SMA), caused by mutations of the survival of motor neuron 1 gene (SMN1), leading to deficiency of SMN protein. Although the splice-switching ASO nusinersen ameliorates SMA when delivered postnatally, substantial deficits can remain in severely affected infants. Here, IA injection of ASOs into two mouse models of severe SMA increased SMN expression in the CNS. In SMAΔ7 mice, which manifest pathology in utero, prenatal treatment improved motor neuron numbers, motor axon development, motor behavioral tests, and survival when compared with those in mice treated postnatally (between P1 and P3). To assess the feasibility of prenatal treatment in a large-animal model, ASOs were delivered midgestation to fetal sheep by IA or intracranial injection. ASOs delivered by IA injection distributed to the spinal cord at therapeutic concentrations and to multiple peripheral tissues without evidence of substantial toxicity to the fetus or mother. These data demonstrated that IA delivery of ASOs holds potential as a minimally invasive approach for prenatal treatment of SMA and possibly other severe, early-onset neurological disorders.

Functionalized Interventional System for in Situ Hematologic Cell Capture

Noninvasive prenatal diagnosis based on fetal cells (cell-based NIPD) offers a safer alternative to traditional invasive procedures but remains limited by the low abundance of fetal nucleated red blood cells (FNRBCs) in maternal circulation and the inefficiency of current isolation techniques. Here, we present a functionalized interventional system for in situ hematologic cell capture (FISHC) directly from peripheral blood, eliminating the need for blood withdrawal and ex vivo processing. FISHC features a carboxybetaine methacrylate (CBMA)-functionalized medical wire with immobilized FNRBC-specific antibodies, enabling high-specificity cell capture under physiological conditions. In vivo validation in a pregnant monkey model confirms its feasibility for efficient and minimally invasive fetal cell retrieval. FISHC represents a paradigm shift in cell-based NIPD and holds promise for broader biomedical applications, including circulating tumor cell detection and real-time liquid biopsy technologies.

Opportunities and Challenges of Fetal Gene Therapy

OBJECTIVE

Fetal gene therapy represents a promising approach to treat severe congenital disorders by intervening during a critical developmental period. This review aims to explore the unique advantages, specific applications, and challenges of this early intervention strategy.

METHOD

We reviewed preclinical and emerging clinical studies evaluating the biological rationale, feasibility, and therapeutic potential of gene therapy administered in utero.

RESULTS

The fetal window offers unique advantages, including enhanced tissue accessibility and biodistribution, immune tolerance to new therapeutic molecules, and has the potential to prevent irreversible organ damage before birth. However, this approach requires ethical considerations including risks to both the fetus and mother, complexities of informed consent, and broad societal implications.

CONCLUSION

Although substantial challenges remain, fetal gene therapy has the potential to improve outcomes in early-onset severe disorders that currently lack effective postnatal treatments.

Prenatal Screening for CMV Primary Infection: A Cost-Utility Model

OBJECTIVE

Congenital cytomegalovirus (CMV) infection is a major cause of deafness and neurodevelopmental disability in children. Our objective was to assess the cost utility of first-trimester serological CMV screening, compared to screening of high-risk pregnancies and no serological screening.

DESIGN

A decision-analytic model was created to compare the cost utility of three strategies from a healthcare sector perspective: universal first-trimester serological screening, screening only of high-risk pregnant women (both including antiviral prophylaxis in cases of primary infection) and serological testing triggered by foetal morphological ultrasound (no CMV serological screening).

SETTING

Canada.

POPULATION

Hypothetical population of 80 000 pregnant women.

METHODS

Probability, expected values and cost estimates were derived from published literature and local hospital and national insurance data.

MAIN OUTCOME MEASURE

Cost per maternal and infant quality-adjusted life year (QALY) lost.

RESULTS

Universal serological screening was superior to both screening of high-risk women and no screening (utility of -0.42, -0.63 and - 0.87 QALY lost, respectively). Sensitivity analysis demonstrated that universal screening was the most cost-effective strategy regardless of the incidence of primary infection, the acceptability of amniocentesis and the efficacy of antiviral prophylaxis. In the Monte Carlo analyses, universal serological screening was the most cost-effective option in 96.36% of simulations. Universal serological screening would allow detection of 152 cases of primary maternal CMV infection and would prevent 29 cases of congenital CMV infection annually.

CONCLUSION

Our findings support the adoption of a population-based prenatal screening programme for the prevention of congenital CMV infection.

Empowering Patients' Knowledge, Attitude, and Practices in Low Resource Settings: A Study of Pictorial Tools for Pretest Counseling of Invasive Prenatal Diagnostic Procedures

OBJECTIVE

This study aimed to evaluate the effectiveness of a bilingual (English-Telugu) poster in enhancing pregnant individuals' knowledge, attitudes, and practices regarding invasive prenatal diagnosis procedures.

METHODS

A cross-sectional survey involving 100 pregnant individuals attending prenatal diagnostic counseling was conducted. Participants reviewed the bilingual poster and completed a questionnaire assessing their understanding, satisfaction, and anxiety levels.

RESULTS

Quantitative analysis revealed that 83% of participants were unaware of the procedures prior to viewing the poster, while 97% found the poster to be "easy" or "very easy" to understand. Anxiety levels decreased for 90% of participants, with many expressing reassurances about procedure safety. Thematic analysis highlighted the importance of clarity, safety reassurance, and uncertainty reduction in patient education. Suggestions for improvement included adding more language options and enhancing visual elements.

CONCLUSION

The study concludes that culturally tailored visual aids, such as bilingual posters, are valuable tools in improving patient education and alleviating anxiety during prenatal diagnostic counseling. These findings emphasize the need for accessible, patient-centered educational resources to foster informed decision-making.

A systematic review of first-trimester blood biomarkers associated with preterm prelabor rupture of the fetal membranes

Background: Preterm prelabor rupture of the fetal membranes (PPROM) increases the risk of neonatal mortality and morbidity. The etiology behind the condition is multifactorial but believed to result from an overactivation of inflammatory pathways. This systematic review aimed to synthesize the literature behind first-trimester biomarkers associated with PPROM and compare it to literature within the same area for preterm birth.

Methods: A search strategy was performed in PubMed, Embase, and CINAHL from 1993 to 2024 resulting in 14,889 articles screened by two independent authors and presented according to PRISMA guidelines. The biomarkers from the included articles were categorized into four medical headings: The immune system, metabolism and endocrinology, hematology, and reproduction.

Results: Biomarkers associated with PPROM were primarily related to the immune system. C-reactive protein (CRP) and white blood cells (WBC) were often investigated for an association with PPROM but displayed divergent results of varying quality. Decreased concentrations of placental growth factor (PlGF) were associated with PPROM and spontaneous preterm birth, potentially highlighting a shared etiology, making soluble fms-like tyrosine kinase-1 (sFlt-1) interesting to investigate as well.

Conclusion: Most biomarkers were examined in single studies, providing limited data to make significant conclusions about each biomarker. This review encourages further investigation of CRP, WBC, PlGF, and sFlt-1.

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.

Towards a Responsible Implementation of NIPT as a First-Tier Test in Canada: Decision-Makers' Perspectives

OBJECTIVE

To explore decision makers' perspectives on the conditions for a responsible implementation of non-invasive prenatal testing (NIPT) as a first-tier test in Canadian provinces' healthcare systems.

METHOD

A qualitative study was conducted with 16 Canadian decision makers who were interviewed between February 2021 and July 2022. After anonymization and transcription, interviews were coded inductively using thematic analysis.

RESULTS

Our interviews showed the complexity of the decision making environment regarding prenatal screening funding. Participants agreed that NIPT is superior to maternal serum screening as a first-tier test, but they also recognized that first-tier NIPT has limits and barriers. They described the following conditions for its responsible implementation: (1) need for time and evidence; (2) taking stakeholders' perspectives into account; (3) limit costs for the healthcare system; (4) ensure appropriate logistical conditions and harmonize the test offer; (5) ensure appropriate clinical services; (6) ensure informed consent; (7) ensure the test is presented as an individual choice to avoid eugenic concerns.

CONCLUSION

Multiple barriers and issues need to be addressed before moving NIPT from second- to first-tier. Decision makers' perspectives should be contrasted with those of other important stakeholders, including pregnant people, disability advocates and healthcare professionals.

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.

Evaluating the Cost-Effectiveness of Antenatal Screening for Major Structural Anomalies During the First Trimester of Pregnancy: A Decision Model

OBJECTIVE

To assess the cost-effectiveness of modifying current antenatal screening by adding first trimester structural anomaly screening to standard of care second trimester anomaly screening.

DESIGN

Health economic decision model.

SETTING

National Health Service (NHS) in England and Wales.

POPULATION

Pregnant women attending for first trimester antenatal screening.

METHODS

The decision model estimated pregnancy outcomes (maternal and foetal) and 20-year costs for current screening practice and for a policy adding a protocol screening for eight major structural anomalies to the current first trimester ultrasound scan. Event probabilities, costs, and outcomes for the model were informed by meta-analyses, published literature, and expert opinion.

MAIN OUTCOMES MEASURES

Expected numbers of pregnancy outcomes, healthcare costs, and maternal quality-adjusted life years (QALYs). Estimation of the incremental cost-effectiveness ratio (ICER), likelihood of cost-effectiveness, and a value of information (VoI) analysis assessing if further research is needed before making a decision about screening.

RESULTS

First trimester anomaly screening increased mean per woman costs by £11 (95% CI £1-£29) and maternal QALYs by 0.002065 (95% CI 0.00056-0.00358). The ICER was £5270 per QALY and the probability of cost-effectiveness at a willingness to pay value for a QALY of £20 000, exceeded 95%. VoI analysis showed further research would be unlikely to represent value for money. The protocol would likely lead to a reduction in infant healthcare costs and QALYs.

CONCLUSIONS

A protocol to screen for eight major structural anomalies during the first trimester appears to represent value for money for the NHS. The opposing implications for mothers and infants, however, raise complex, challenging, and sensitive issues.

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.

CRISPR/Cas-Based Prenatal Screening for Aneuploidy: Challenges and Opportunities for Early Diagnosis

Aneuploidy is increasingly recognized globally as a common cause of miscarriage among expectant mothers. The existing prenatal screening techniques for detecting aneuploidy have several limitations. The ability to diagnose aneuploidy early in a non-invasive manner is not feasible with the current screening methods, as they may produce false positive or false negative results. Recently, the widely used gene editing tool CRISPR/Cas has shown great promise in diagnostics. This review summarizes the prenatal screening tests used in the first trimester to assess aneuploidy conditions. Additionally, we discuss the advantages and disadvantages of molecular diagnostic tests, including the benefits and challenges of CRISPR/Cas-based trisomy detection. Thus, the proposed prenatal screening using CRISPR/Cas could provide significant benefits to expectant mothers by potentially enabling the early diagnosis of trisomy, helping to prevent miscarriage and birth defects. Furthermore, it opens new avenues for research, allowing clinicians and researchers to develop, optimize, and implement CRISPR/Cas-based prenatal screening assays in the future.

Has the Era of Individualized Intrauterine Treatment for Congenital Adrenal Hyperplasia Arrived?

BACKGROUND

Congenital adrenal hyperplasia (CAH) is a common metabolic genetic disease. Early diagnosis and intervention are crucial to improve the prognosis. Noninvasive prenatal diagnosis (NIPD) is an early, safe, and accurate method. This study aimed to evaluate the NIPD of CAH while guiding individualized intrauterine treatment.

METHODS

Twenty families with a 25% risk of having a baby with 21-hydroxylase deficiency (21-OHD) were included. Haplotypes were constructed based on targeted sequencing and family linkage analysis. Relative haplotype dosage (RHDO) combined with Bayes factor was used to infer fetal genotypes. Invasive prenatal diagnosis was performed to verify the reliability of NIPD. For affected-female fetuses, intrauterine treatment was applied until delivery.

RESULTS

In 20 families, NIPD successfully identified one female-affected fetus, four male-affected fetuses, nine heterozygotes, and five normal fetuses. The first-pass success rate of NIPD was 90% (18/20), the reporting rate was 95% (19/20), and the accuracy was 100% (19/19). Individualized intrauterine treatment avoided 88.9% (8/9) of unnecessary treatment of unaffected female fetuses. Moreover, no significant virilization was observed in the newborn of CAH16, which underwent intrauterine treatment.

CONCLUSION

NIPD has far-reaching implications for the early treatment and clinical management of pregnancy in families with 21-OHD.

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.

Feasibility of multimodal magnetic resonance imaging to assess maternal hyperoxygenation in sheep pregnancy

An adequate supply of oxygen is crucial for optimal fetal growth and development. Estimation of quantitative indices that reflect tissue diffusivity and oxygenation have been enabled by advances in magnetic resonance imaging (MRI) technology. However, the current diagnostic tools in clinical obstetrics, such as Doppler ultrasound measurements of umbilical blood flow and cardiotocography, do not offer direct information about the oxygen supply to the fetus, nor placental function in vivo. Although MRI provides an opportunity to identify critical changes in fetal oxygenation, exact tissue oxygen content cannot be established in humans. Preclinical models such as pregnant sheep allow the use of invasive methods to validate MRI measurements. The present study investigates the relationship between changes in MRI signal and conventional blood gas analyser measurements during normoxic and hyperoxic conditions in pregnant sheep. Several studies have reported an increase in human fetal oxygenation during 100% maternal oxygen inhalation. We investigated the physiological impact of maternal hyperoxygenation on the placenta in normal pregnant sheep using multimodal functional MRI. Using a multicompartment MRI signal model, we observed the expected increase in feto-placental oxygen saturation with maternal hyperoxygenation. In addition, maternal hyperoxygenation resulted in a significant increase in blood-oxygenation-level-dependent (BOLD) signal intensities, suggesting that BOLD MRI allows non-invasive assessment of the feto-placental response to maternal hyperoxygenation in sheep. Our data suggest that diffusion and relaxation-based MRI is sensitive to acute changes in maternal and feto-placental oxygenation and demonstrate a link between MRI-parameter estimated and reference oxygen saturation. KEY POINTS: Quantification of feto-placental oxygenation and function are important for correct differential diagnosis of placental insufficiency. The only current method for obtaining information about fetal oxygen delivery is cordocentesis. However, there is a risk of inducing preterm birth and/or fetal loss associated with the procedure. Magnetic resonance imaging (MRI) can estimate changes in oxygenation in specific areas of placental and fetal tissue. Using the DECIDE (i.e. diffusion-relaxation combined imaging for detailed placental evaluation) multicompartment model that is sensitive to changes in maternal and feto-placental oxygenation and the blood-oxygenation-level-dependent (BOLD) MRI technique in the sheep fetus, we have demonstrated that maternal hyperoxygenation increases oxygenation of fetal tissue in the placenta. There was a differential effect according to placentome morphological type. This study shows a link between MRI estimated parameters and reference maternal and fetalS O 2 ${{S}_{{{{\mathrm{O}}}_2}}}$ andP O 2 ${{P}_{{{{\mathrm{O}}}_2}}}$ by blood gas analyser, supporting the possibility of using multimodal MRI for measuring regional changes in tissue oxygenation in vivo.

Consecutive 5-year outcomes of chorionic villus sampling at a tertiary center

This study shares our 5-year experience with chorionic villus sampling (CVS) and analyzes the indications, results, and complications of this procedure. We conducted a retrospective analysis of data from singleton pregnancies that underwent CVS between 2015 and 2020 at the Maternal-Fetal Medicine Unit of Health Science University, Izmir Tepecik Research, and Training Hospital. Maternal demographics, indications, karyotype results, and pregnancy outcomes were recorded. We retrospectively analyzed data from 468 CVS procedures, conducted between 2015 and 2020. The most common indications for CVS were positive screening test results in the first trimester, fetal structural abnormalities, and increased nuchal translucency (NT) observed during ultrasound. Fetal structural abnormalities had the highest detection rate, at 34.5% for chromosomal abnormalities, followed by increased NT and first-trimester screen-positive test results (26.9% and 11.3%), respectively. The culture success rate was 96.3% (451 out of 468). The most prevalent chromosomal abnormalities were numerical, including Trisomy 21 (10.9%), Trisomy 18 (4.2%), and Trisomy 13 (1.9%). Results could not be obtained in 17 patients (3.6%); 12 (2.5%) were due to insufficient samples and culture failure, while 5 (1.06%) were due to maternal contamination. Amniocentesis was required as a secondary sampling in 24 cases (5.1%) and performed in 17 cases (3.6%). This study emphasizes the significance of CVS in prenatal diagnosis and the management of high-risk pregnancies. However, we must be aware of the associated risks and limitations, which include culture success rates, inconclusive results, and the occasional need for secondary sampling.

Noninvasive prenatal diagnosis (NIPD) of non-syndromic hearing loss (NSHL) for singleton and twin pregnancies in the first trimester

BACKGROUND

Noninvasive prenatal diagnosis (NIPD) has been proven feasible for non-syndromic hearing loss (NSHL) in singleton pregnancies. However, previous research is limited to the second trimester and the application in twin pregnancies is blank. Here we provide a novel algorithmic approach to assess singleton and twin pregnancies in the first trimester.

METHODS

A 324.614 kb capture panel was designed to selectively enrich target regions. Parental haplotypes were constructed by target sequencing of blood samples from the parents and the proband. Then single nucleotide polymorphisms (SNP) within target regions were classified into four and six categories in singleton and twin pregnancy, respectively. Combining relative haplotype dosage change (RHDO) and the Bayes factor (BF), fetal fraction (FF) and fetal genotype were deduced in singleton and twin pregnancies. The pregnant women's NIPD results were validated by invasive prenatal diagnosis and Sanger sequencing.

RESULTS

Sixteen women with singleton pregnancies and one woman with a twin pregnancy were recruited. Among the 16 singleton pregnancies, NIPD was successfully applied in 15 families and the coincidence rate with invasive prenatal diagnosis was 100% (15/15). Only one family NIPD result is "no call" because the imbalance distribution of SNP sites makes it difficult to estimate recombination events. Most (13/15) of pregnant women were diagnosed in the first trimester and the earliest gestation week was the 7th week. The twin pregnancy was a dichorionic diamniotic twin (DCDA). NIPD confirmed one fetus is affected, and another is a carrier with c.299_300delAT of GJB2 gene.

CONCLUSION

This study represents the pioneering evidence in the field, demonstrating the feasibility of NIPD for NSHL in twin pregnancies. Moreover, it provides a novel and advanced diagnostic approach for families at high risk of NSHL during pregnancy, offering earlier detection, enhanced safety, and improved accuracy.

Decisional conflict, anxiety, and social support among Chinese pregnant women making further prenatal testing decisions

OBJECTIVE

This study aimed to examine decisional conflict and identify its predictors in Chinese pregnant women who were making decisions about further prenatal testing after receiving a screening result of high-risk for Down syndrome.

METHOD

A cross-sectional study was conducted from September 2020 to July 2021 in Guangzhou, China. Two-hundred and sixty pregnant women receiving a screening result of high-risk for Down syndrome completed a questionnaire comprising the Decisional Conflict Scale, Self-rating Anxiety Scale, and Social Support Rating Scale.

RESULTS

The mean decisional conflict score was 28.8 ± 13.6, representing a moderate level. Advanced age (≥35 years), having a religious belief, not knowing about non-invasive or invasive prenatal testing, choosing NIPT for further prenatal testing, high levels of anxiety, and low levels of social support were significant predictors of decisional conflict, explaining 28.4% of its variance (F = 18.115, p < 0.001).

CONCLUSIONS

The results highlighted the necessity of assessing patients' decisional conflict and providing adequate interventions along the prenatal care trajectory. The results also showed that providing good support has an essential value for women by relieving their decisional conflict.

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.

Non-invasive prenatal detection of dominant single-gene disorders in fetal structural abnormalities: a clinical feasibility study

OBJECTIVE

This study evaluated the accuracy of non-invasive prenatal testing (NIPT-SGDs) for dominant monogenic genetic diseases associated with fetal structural abnormalities and to assess the feasibility of clinical application.

METHODS

Pregnant women requiring prenatal diagnosis due to fetal structural abnormalities were enrolled. Maternal peripheral blood was analyzed for cell-free DNA (cfDNA) using coordinative allele-aware target enrichment sequencing (COATE-seq). This assessed fetal allele depth distribution, fraction and variation ratio. The variation's origin was then determined to obtain fetal variation information. Finally, NIPT-SGDs results were confirmed via invasive prenatal diagnosis (IPD).

RESULTS

Upon examination of 113 samples using NIPT-SGDs, COATE-seq successfully analyzed 112 for fetal variation, excluding one due to hemolysis. The study detected six positive cases, yielding a 5.36% detection rate. These disorders included tuberous sclerosis complex (TSC1 and TSC2 being its causative genes), Noonan syndrome (PTPN11), polycystic kidney disease (PKD1), and Kabuki syndrome (KMT2D), occurring twice each, except for Noonan and polycystic kidney disease. Two false positives were due to the mother being a genetic mosaicism. Compared to invasive whole-exome sequencing (WES), NIPT-SGDs did not detect nine positive cases of IPD dominant monogenic diseases, accurately identifying 90.18% (101/112) of the actual positive and negative cases.

CONCLUSION

Our findings demonstrate the clinical utility of NIPT-SGDs using COATE-seq in effectively identifying fetuses with dominant single-gene disorders. Furthermore, this method can be applied to all fetuses.

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.

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 online 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.

SUMMARY STATEMENTS

RECOMMENDATIONS.

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.

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.

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.

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.

Informal Prenatal Genetic Screening Education: What can you learn from Google and YouTube?

Introduction

The goal of this paper is to explore what online education and decision support tools are freely available to patients about prenatal screening.

Materials and Methods

We 1) conducted an environmental scan using Google Trends to identify and evaluate prenatal screening search terms, 2) created a list of websites and YouTube videos that would be easily accessed by a searcher and 3) characterized the information within those websites and videos, including an examination of their qualities as a decision support tool and a readability analysis.

Results

Fifty websites, containing 62 unique educational resources, and 39 YouTube videos were analyzed. The websites were primarily educational, though the education was provided by a range of sources including non-profit and for-profit organizations, universities, and governments (i.e., public health departments). Readability scores (PEMAT-P) for the sites ranged from 50% to 92%, with a median score of 74%. Two of the websites we evaluated met all of the limited decision support standards we applied; four of the websites included patient stories or experiences and eight included some element of values clarification. Videos were more likely to include values clarification.

Discussion

The information available to patients online is variable. While most is balanced and informative, much is difficult to read and missing key decision-making factors. Healthcare providers should work with patients to ensure they have basic comprehension of the prenatal genetic screening materials, possible result outcomes, and expected steps following a positive screening result.

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.