Procedure-related risk of miscarriage following amniocentesis and chorionic villus sampling: a systematic review and meta-analysis

Non-invasive prenatal testing of pregnancies at risk for phenylketonuria

BACKGROUND

Phenylketonuria (PKU) is a common metabolic disorder caused predominately by mutations in the phenylalanine hydroxylase (PAH) gene. The aim of the study was to design and validate the performance of a non-invasive prenatal test (NIPT) for PKU using circulating single molecule amplification and resequencing technology (cSMART).

METHODS

A total of 18 couples at genetic risk for having a child with PKU were recruited to the study. Gold standard invasive prenatal diagnosis (IPD) was performed on amniocyte or villus cell DNA by Sanger sequencing, targeting the known parental PAH mutations. Retrospectively, NIPT was also performed on stored maternal plasma samples from the 18 pregnancies by a multiplex cSMART assay designed to target all known DNA variants in the PAH gene.

RESULTS

Benchmarking against IPD results, NIPT correctly genotyped all fetuses, including six compound heterozygotes with PKU, four normal non-carriers of PKU and eight heterozygote carriers of PKU comprising five cases of a maternally inherited mutation and three cases of a paternally inherited mutation.

CONCLUSIONS

The NIPT cSMART PKU assay was highly sensitive and specific for mutation detection and correct assignment of fetal genotypes. Based on comprehensive mutation coverage across the PAH gene, the assay may initially have clinical utility as a pregnancy screening test for high-risk carrier couples.

Chorionic villous sampling-related complications: a cohort study

Purpose: To compare the adverse pregnancy outcomes between the pregnant women undergoing chorionic villous sampling (CVS) and those without CVS.Materials and methods: A cohort study was conducted on low risk pregnancies attending Chiang Mai University Hospital between years 2003 and 2017 and identify the database of women undergoing CVS (study group) and control group. Each case in study group was matched for 10 cases of the control by maternal age and year of procedure.Results and conclusions: Of 1384 pregnancies undergoing CVS, 776 cases met criteria and were matched with 7760 controls. The gestational age at delivery and actual birth weight were significantly different between two groups (38.02 versus 38.96 weeks, p value <.001 and 3025 versus 3092 g, p value .001). Moreover, CVS group had significantly higher preterm birth (9.4 versus 7.3%, p value .037; RR 1.287, 95% CI 1.017-1.629). However, there was no significant difference in fetal loss rate before 24 weeks (1.16 versus 1.9%, p value .14), small for gestational age (SGA); SGA (4 versus 4%, p value .948) and low birth weight (LBW); LBW (8.9 versus 8.0%, p value .41). Pregnancies undergoing CVS tend to deliver earlier and has significantly higher preterm birth. However, the incidences of fetal loss, SGA and LBW are not significantly increased.

Intra-amniotic Sildenafil Treatment Modulates Vascular Smooth Muscle Cell Phenotype in the Nitrofen Model of Congenital Diaphragmatic Hernia

The etiology of pulmonary vascular abnormalities in CDH is incompletely understood. Studies have demonstrated improvement in pulmonary vasculature with prenatal therapy in animal models. We hypothesize that prenatal sildenafil may attenuate defective pulmonary vascular development via modulation of vSMC phenotype from undifferentiated, proliferative phenotype to differentiated, contractile phenotype. We utilized the nitrofen model of CDH to examine the effect of IA sildenafil on pulmonary vSMC phenotype during lung development. Timed-pregnant CD-1 mice were gavage fed 25 mg nitrofen or olive oil (control) at E8.5 of gestation. Single IA injections of Sildenafil (Revatio; 10 µL of 4 mg/4 ml solution) or dextrose control were performed at E12.5. Mice were sacrificed on various gestational days for embryonic lung harvest. Markers of vSMC development of undifferentiated and differentiated phenotypes were analyzed by immunostaining and western blot. Across all time points in gestation, nitrofen-treated embryonic lungs demonstrated increased vSMC expression of NOTCH3, Hes-5, PDGFR-β, desmin and α-SMA and decreased expression of calponin and SMMHC, compared to oil controls. IA dextrose treatment had no effect on expression levels. However, IA Sildenafil treatment resulted in down-regulation of NOTCH3, Hes-5, PDGFR-β, desmin and α-SMA and upregulation of calponin and SMMHC, comparable to oil controls. In the nitrofen model, vSMC express markers consistent with more undifferentiated proliferative phenotype, resulting in hypermuscularization of intrapulmonary arterioles in CDH. A single dose of IA Sildenafil treatment early in gestation, results in sustained normalization of vSMC phenotype. Pharmacologic modulation of the vSMC phenotype at key gestational points may have therapeutic potential.

Single Nucleotide Polymorphism-Based Noninvasive Prenatal Testing: Experience in India

INTRODUCTION

Noninvasive prenatal testing (NIPT) has revolutionized prenatal screening for chromosomal aneuploidies in some countries. Its implementation has been sporadic in developing countries. Given the genetic variation of the people in different countries, we evaluated the performance of the SNP-based NIPT in India .

MATERIALS AND METHODS

The Panorama™ NIPT was performed in 516 pregnancies, which had tested intermediate-to-high risk on conventional first and second trimester screening. Results were confirmed either by invasive diagnostic testing or by clinical evaluation after birth.

RESULTS

Of 511 samples analyzed, results were obtained in 499 (97.7%). Of these, 480 (98.2%) were low risk and 19 were high risk. A sensitivity of 100% was obtained for detection of trisomies 21, 18, 13 and sex chromosomal abnormalities. The specificity ranged from 99.3 to 100% for abnormalities tested. Taken together, the positive predictive value for trisomies 21, 18, 13 and monosomy X was 85.7%. The average fetal fraction was 8.2%, which is lower than the average observed elsewhere.

CONCLUSION

This is the first report of detailed experience with NIPT in India and demonstrates comparable performance in all aspects of testing to the results elsewhere.

A Reappraisal of Circulating Fetal Cell Noninvasive Prenatal Testing

New tools for higher-resolution fetal genome analysis including microarray and next-generation sequencing have revolutionized prenatal screening. This article provides commentary on this rapidly advancing field and a future perspective emphasizing circulating fetal cell (CFC) utility. Despite the tremendous technological challenges associated with their reliable and cost-effective isolation from maternal blood, CFCs have a strong potential to bridge the gap between the diagnostic sensitivity of invasive procedures and the desirable noninvasive nature of cell-free fetal DNA (cffDNA). Considering the rapid advances in both rare cell isolation and low-input DNA analysis, we argue here that CFC-based noninvasive prenatal testing is poised to be implemented clinically in the near future.

A Practical Guide to the Management of the Fetus and Newborn With Hemophilia

Newborns with hemophilia are at risk of intracranial hemorrhage, extracranial hemorrhage, and other bleeding complications. The safe delivery of a healthy newborn with hemophilia is a complex process that can begin even before conception, and continues throughout pregnancy, birth, and the newborn period. This process involves the expectant parents and a wide variety of health-care professionals: genetic counselors, obstetricians, neonatologists, pediatricians, radiologists, adult and pediatric hematologists, and nurses with expertise in hemophilia. Because of this multidisciplinary complexity, the relative rarity of births of newborns with hemophilia, and the lack of high-quality evidence to inform decisions, there is considerable variation in practice in this area. We present a comprehensive multidisciplinary approach, from preconception counseling to discharge planning after birth, and describe available options for management decisions. We highlight a number of areas of important uncertainty and controversy, including the preferred mode of delivery, the appropriate use and timing of neuroimaging tests, and the appropriate use of clotting factor concentrates in the newborn period. While the approach presented here will aid clinicians in planning and providing care, further research is required to optimize the care of newborns with hemophilia.

Prenatal diagnosis by chromosomal microarray analysis

Chromosomal microarray analysis (CMA) is performed either by array comparative genomic hybridization or by using a single nucleotide polymorphism array. In the prenatal setting, CMA is on par with traditional karyotyping for detection of major chromosomal imbalances such as aneuploidy and unbalanced rearrangements. CMA offers additional diagnostic benefits by revealing sub-microscopic imbalances or copy number variations that are too small to be seen on a standard G-banded chromosome preparation. These submicroscopic imbalances are also referred to as microdeletions and microduplications, particularly when they include specific genomic regions that are associated with clinical sequelae. Not all microdeletions/duplications are associated with adverse clinical phenotypes and in many cases, their presence is benign. In other cases, they are associated with a spectrum of clinical phenotypes that may range from benign to severe, while in some situations, the clinical significance may simply be unknown. These scenarios present a challenge for prenatal diagnosis, and genetic counseling prior to prenatal CMA greatly facilitates delivery of complex results. In prenatal diagnostic samples with a normal karyotype, chromosomal microarray will diagnose a clinically significant subchromosomal deletion or duplication in approximately 1% of structurally normal pregnancies and 6% with a structural anomaly. Pre-test counseling is also necessary to distinguish the primary differences between the benefits, limitations and diagnostic scope of CMA versus the powerful but limited screening nature of non-invasive prenatal diagnosis using cell-free fetal DNA.

Managing pain and anxiety during transabdominal chorionic villus sampling. A noninferiority randomized trial of nitrous oxide vs local anesthesia

INTRODUCTION

Transabdominal chorionic villus sampling (CVS) is an invasive procedure for prenatal diagnosis reported to be associated with anxiety and pain. In this context, the need for analgesia during CVS has been considered useful. Even though several authors have been interested in pain management during amniocentesis, no study has been published on pain reduction during CVS. Our objective was to evaluate pain and anxiety management during transabdominal CVS using nitrous oxide (N₂ O) and local anesthesia.

MATERIAL AND METHODS

In a randomized controlled noninferiority trial, self-administered nitrous oxide (N₂ O) inhalation (equimolar premix of oxygen and nitrous oxide) was compared with local anesthesia (1% lidocaine) before CVS. Primary outcome was pain and secondary outcome was anxiety, both measured on a visual analog scale 30-60 minutes before, immediately after (5-10 minutes) and 30-60 minutes after CVS. With a statistical power of 90%, type I error of 5% and two-sided test and potential exclusions, a sample size of 96 patients per group was enrolled and randomized. No patient was enrolled before the trial registration date.

RESULTS

From 13 March 2013 through 10 February 2015, 192 patients (96 per group) were screened and randomized. Most characteristics were similar across groups. Pain in the N₂ O group was 2.65 ± 0.22 vs 3.32 ± 0.26 in local anesthesia group [mean ± standard error of mean  (SEM)]. Mean anxiety in the N₂ O group was 3.17 ± 0.27 vs 5.19 ± 0.30 in the local anesthesia group.

CONCLUSION

N₂ O was as efficient and even superior to local anesthesia for both pain and anxiety reduction during CVS, as the 95% confidence intervals were both below the prespecified noninferiority margin of 0.8 and below zero.

Strategies to minimize false positives and interpret novel microdeletions based on maternal copy-number variants in 87,000 noninvasive prenatal screens

BACKGROUND

Noninvasive prenatal screening (NIPS) of common aneuploidies using cell-free DNA from maternal plasma is part of routine prenatal care and is widely used in both high-risk and low-risk patient populations. High specificity is needed for clinically acceptable positive predictive values. Maternal copy-number variants (mCNVs) have been reported as a source of false-positive aneuploidy results that compromises specificity.

METHODS

We surveyed the mCNV landscape in 87,255 patients undergoing NIPS. We evaluated both previously reported and novel algorithmic strategies for mitigating the effects of mCNVs on the screen's specificity. Further, we analyzed the frequency, length, and positional distribution of CNVs in our large dataset to investigate the curation of novel fetal microdeletions, which can be identified by NIPS but are challenging to interpret clinically.

RESULTS

mCNVs are common, with 65% of expecting mothers harboring an autosomal CNV spanning more than 200 kb, underscoring the need for robust NIPS analysis strategies. By analyzing empirical and simulated data, we found that general, outlier-robust strategies reduce the rate of mCNV-caused false positives but not as appreciably as algorithms specifically designed to account for mCNVs. We demonstrate that large-scale tabulation of CNVs identified via routine NIPS could be clinically useful: together with the gene density of a putative microdeletion region, we show that the region's relative tolerance to duplications versus deletions may aid the interpretation of microdeletion pathogenicity.

CONCLUSIONS

Our study thoroughly investigates a common source of NIPS false positives and demonstrates how to bypass its corrupting effects. Our findings offer insight into the interpretation of NIPS results and inform the design of NIPS algorithms suitable for use in screening in the general obstetric population.

Risk of congenital toxoplasmosis in women with low or indeterminate anti-Toxoplasma IgG avidity index in the first trimester of pregnancy: an observational retrospective study

OBJECTIVES

Congenital toxoplasmosis (CT) affects one to ten fetuses per 10 000 live newborns in western countries. Without knowing pre-conception serostatus, it is hard to date the infection when anti-Toxoplasma IgG and IgM antibodies are positive at first screening. Although a high IgG avidity index (AI) in the first trimester excludes CT, the same cannot be said of intermediate and low AI. The aim of this study was to estimate the risk of CT when intermediate or low AI is detected in the first trimester of pregnancy.

METHODS

Our observational retrospective study enrolled women with positive anti-Toxoplasma IgG and IgM, and low/intermediate AI in the first trimester of gestation seen at two reference centres in northern Italy between 2006 and 2015. All women received spiramycin. When requested by women, a sample of fluid obtained through amniocentesis was tested with a commercial real-time PCR. CT was defined by positive PCR result confirmed on aborted materials or by newborn follow up.

RESULTS

Overall, 778 first-trimester pregnant women were included; AI was low in 532/778 (68%) and intermediate in 246/778 (32%). Amniocenteses were performed in 528/778 (67.9%), with no fetal loss. In all, 19/778 (2.4%) miscarriages and 15/778 (1.9%) pregnancy terminations were recorded; 9/778 (1.6%) were lost to follow up. In two women, PCR on amniotic fluid was positive, but CT was confirmed in only 1/747 cases (0.13%, 95% CI 0.02%-0.75%).

CONCLUSION

In our study, the risk of CT was much lower than anticipated. These data must be considered when counselling these women.

Prenatal screening for genetic disorders: Suggested guidelines for the Indian Scenario

Prenatal testing is the best strategy for reducing the burden of genetic disorders and congenital disabilities that cause significant postnatal functional impairment. Universal prenatal screening is advisable for common genetic disorders and congenital anomalies such as Down syndrome, beta-thalassaemia and neural tube defects. Several prenatal-screening tests are now available for Down syndrome, but knowledge about the appropriate timing of the test and the need for pre- and post-test counselling may not be updated among the primary care physicians. There is also a considerable degree of confusion regarding the prenatal screening test to be chosen in each case, due to the availability of a number of new and advanced screening techniques. At present, there is no nation-wide consensus regarding the nature and timing of these prenatal-screening protocols. Due to the absence of any definite guidelines and the additional lacunae in the awareness regarding the appropriate prenatal screening in the country, the optimum benefits of these screening protocols are not reaching the population. This review focuses on the various prenatal screening and diagnostic tests that are available for common genetic conditions and congenital disabilities and attempts to outline the most cost-effective and gestational age-appropriate strategies for prenatal screening for the Indian healthcare set-up. The recommendations suggested would serve as a source guide for formulating prenatal-screening guidelines for reducing the incidence of common genetic disorders and congenital disabilities in India.

Use of a novel computerized decision aid for aneuploidy screening: a randomized controlled trial

Purpose:

To assess whether knowledge following use of a decision aid (DA) for aneuploidy screening and testing is inferior to knowledge in women who saw a genetic counselor (GC) only.

Methods:

This is a randomized controlled noninferiority trial of pregnant women at ≤22 weeks. Women who were scheduled for GC were randomly allocated to use a DA before GC or to GC alone. The primary outcome was knowledge score, comparing women who had used the DA only to those who saw GC alone. Analysis was by intent to treat.

Results:

Between 01–10/2017, 197 women were randomized, 105 to GC only and 92 to DA use before GC. Demographics and baseline knowledge were similar between groups. Mean knowledge score following DA use was not inferior to mean knowledge score following GC only (10.4 vs 10.6, p=0.306). Decisional conflict was similar following completion of the DA to following GC only, but was reduced following completion of both the DA and GC compared to GC only (0.22 vs. 1.74, p=0.003).

Conclusion:

Knowledge surrounding aneuploidy screening in women who used a DA was not inferior to knowledge in women who underwent GC. Use of the DA in addition to GC reduced decisional conflict.

Noninvasively diagnosing for fetal trisomy 21 by examining heterozygous single nucleotide polymorphisms in the placental specific genes on chromosome 21

OBJECTIVE

Noninvasive prenatal diagnosing for fetal trisomy 21 could help to avoid unnecessary amniocentesis. It is feasible to target the cell-free placental-specific mRNA in maternal plasma, thus eliminating the interference from the maternal genetic background.

STUDY DESIGN

In this study, placental-specific genes on chromosome 21 were identified by searching the TiGER database and reviewing the published literature. These cell-free placental-specific mRNA fragments in maternal plasma were amplified and sequenced. Then, the allelic ratio of heterozygous single-nucleotide polymorphisms(SNPs) was analyzed.

RESULTS

Four placental-specific genes (DNMT3L, KRTAP26-1, PLAC4, DSCR4) were identified. This study included 42 cases of normal pregnancies and 19 cases of trisomy 21 pregnancies. The probability density function showed that the allelic ratio of heterozygous SNPs in normal pregnancy reached a peak at 1.0, and that in the trisomy 21 pregnancy was a double-peaked curve in both 0.5 and 2.0. However, the allelic ratio of heterozygous SNPs demonstrated no statistical difference between the normal and trisomy 21 pregnancies.

CONCLUSION

Fetal trisomy 21 could not be diagnosed by examining the heterozygous SNPs of cell-free placental-specific mRNA on chromosome 21. This might be because the low quantity and quality of cell-free placental-specific mRNA fragments in maternal plasma, and the limited available heterozygous SNPs on the placental-specific genes.

Frequency-enhanced transferrin receptor antibody-labelled microfluidic chip (FETAL-Chip) enables efficient enrichment of circulating nucleated red blood cells for non-invasive prenatal diagnosis

Fetal aneuploidy and other chromosomal aberrations affect 9 in 1000 live births. Unlike the invasive diagnosis with high risk of miscarriage, non-invasive prenatal diagnosis (NIPD) sampling from maternal blood becomes a promising way for fetal genetic screening. However, fetal cell-based NIPD has a major challenge due to the small number of fetal cells present in maternal blood. We designed a frequency-enhanced transferrin receptor antibody-labelled microfluidic chip (FETAL-Chip) for efficient enrichment and identification of circulating fetal cells, i.e., circulating nucleated red blood cells (cNRBCs) from maternal blood. The FETAL-Chip can dramatically enhance the interaction of fetal cells with antibody-coated microposts to increase the capture efficiency while minimizing nonspecific adsorption. With the help of immunostaining, we can identify cNRBCs from as little as 2 milliliter maternal blood. Various numbers of cNRBCs were detected from volunteers as early as 7 weeks after conception and throughout the entire pregnancy. Gene analysis was also carried out to confirm the fetal origin of captured cells. With easy, non-invasive and highly efficient enrichment of cNRBCs, the method presented here offers great potential for non-invasive prenatal diagnosis.

Do patients who achieve pregnancy using IVF-PGS do the recommended genetic diagnostic testing in pregnancy?

PURPOSE

Patients undergoing in-vitro fertilization (IVF) with preimplantation genetic screening (PGS) are counseled about the limitations of this technique. As part of the consent process for PGS, physicians recommend diagnostic genetic testing performed in early pregnancy to definitively rule out chromosomal abnormalities. We have noted anecdotally, however, that few patients undergo the recommended diagnostic testing. In this study, we are examining if women who conceived using IVF-PGS did early pregnancy chromosomal testing, and if they did, what type of testing they had.

METHODS

This study was performed from 2015 to 2017 in the Division of Reproductive Endocrinology and Infertility at Northwestern University. We included patients who became pregnant after IVF-PGS who were seen by the Division of Reproductive Genetics and non-PGS control group.

RESULTS

Sixty-eight patients were included. A total of 50 patients (73.5%) opted for non-invasive prenatal screening; 5 (7.4%) had invasive testing (4 had chorionic villus sampling and 1 had amniocentesis). A total of 13 patients (19%) declined further genetic testing. When comparing demographic data, the mean age was significantly higher in the group of patients who pursued non-invasive testing than in the group who declined further testing (37.15 vs 34.05 years old, p < 0.05). Control group declined invasive diagnostic testing.

CONCLUSIONS

Most patients who conceive using IVF-PGS do not pursue diagnostic prenatal chromosomal testing. Future studies focusing on decision making in this patient group are warranted to further elucidate why a small percentage of patients opt for diagnostic testing, even when adequately counseled about the inherent limitations of PGS.

Effect of Cell-Free DNA Screening vs Direct Invasive Diagnosis on Miscarriage Rates in Women With Pregnancies at High Risk of Trisomy 21: A Randomized Clinical Trial

IMPORTANCE

Cell-free DNA (cfDNA) tests are increasingly being offered to women in the first trimester of pregnancies at a high risk of trisomy 21 to decrease the number of required invasive fetal karyotyping procedures and their associated miscarriages. The effect of this strategy has not been evaluated.

OBJECTIVE

To compare the rates of miscarriage following invasive procedures only in the case of positive cfDNA test results vs immediate invasive testing procedures (amniocentesis or chorionic villus sampling) in women with pregnancies at high risk of trisomy 21 as identified by first-trimester combined screening.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted from April 8, 2014, to April 7, 2016, in 57 centers in France among 2111 women with pregnancies with a risk of trisomy 21 between 1 in 5 and 1 in 250 following combined first-trimester screening.

INTERVENTIONS

Patients were randomized to receive either cfDNA testing followed by invasive testing procedures only when cfDNA tests results were positive (n = 1034) or to receive immediate invasive testing procedures (n = 1017). The cfDNA testing was performed using an in-house validated method based on next-generation sequencing.

MAIN OUTCOMES AND MEASURES

The primary outcome was number of miscarriages before 24 weeks' gestation. Secondary outcomes included cfDNA testing detection rate for trisomy 21. The primary outcome underwent 1-sided testing; secondary outcomes underwent 2-sided testing.

RESULTS

Among 2051 women who were randomized and analyzed (mean age, 36.3 [SD, 5.0] years), 1997 (97.4%) completed the trial. The miscarriage rate was not significantly different between groups at 8 (0.8%) vs 8 (0.8%), for a risk difference of -0.03% (1-sided 95% CI, -0.68% to ∞; P = .47). The cfDNA detection rate for trisomy 21 was 100% (95% CI, 87.2%-100%).

CONCLUSIONS AND RELEVANCE

Among women with pregnancies at high risk of trisomy 21, offering cfDNA screening, followed by invasive testing if cfDNA test results were positive, compared with invasive testing procedures alone, did not result in a significant reduction in miscarriage before 24 weeks. The study may have been underpowered to detect clinically important differences in miscarriage rates.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02127515.

Amniotic Fluid Stem Cells for the Treatment of Surgical Disorders in the Fetus and Neonate

Over the past decade, amniotic fluid‐derived stem cells have emerged as a novel experimental approach aimed at improving outcomes in children with congenital anomalies, including spina bifida, heart defects, and diaphragmatic hernia. Interest in these cells for the treatment of prenatally diagnosed diseases has arisen based on numerous studies demonstrating the relative ease of harvesting an abundant quantity of amniocytes from a small aliquot of fluid, the unique properties of amniocytes themselves, and the beneficial effects of amniotic fluid‐derived stem cells in experimental animal models. This report gives a brief overview of the rationale and current status of amniotic fluid stem cell‐based therapies, focusing on its relevance to birth defects affecting the fetus and neonate. The author proposes a roadmap for further study that would be required prior to clinical application of amniotic fluid stem cell technologies. stem cells translational medicine2018;7:767–773

Diagnosis of Fetal Structural Anomalies at 11 to 14 Weeks

OBJECTIVES

To assess the performance of first-trimester ultrasound (US) in identifying major fetal structural abnormalities in an unselected population.

METHODS

We conducted a retrospective analysis of all pregnancies that underwent the 11- to 14-week scan in the Fetal Medicine Department of Filantropia Hospital in Bucharest, which were prospectively examined within our screening program. The purpose of the first-trimester US was to evaluate the risk for chromosomal abnormalities and to conduct fetal anatomic examination using a detailed protocol.

RESULTS

Our population consisted of 7480 pregnant patients (7576 fetuses). The follow-up was completed for 6045 patients (6114 fetuses). The prevalence of major structural anomalies was 1.89%. In the first trimester, we identified 79% of all major structural anomalies. The highest detection rates were achieved for abdominal wall defects (100%), major central nervous system anomalies (88%), cardiac defects (74%), and skeletal anomalies (71%). The nuchal translucency was increased in 35% of the cases with structural anomalies, and 95% of these were diagnosed in the first trimester. Seventy percent of the patients who presented with structural anomalies and a normal nuchal translucency were diagnosed in the first trimester.

CONCLUSIONS

Our results emphasize the importance of performing a detailed US examination at 11 to 14 weeks' gestation in identification of fetal structural defects.

Risk Factors for Early Dialysis Dependency in Autosomal Recessive Polycystic Kidney Disease

OBJECTIVE

To identify prenatal, perinatal, and postnatal risk factors for dialysis within the first year of life in children with autosomal recessive polycystic kidney disease (ARPKD) as a basis for parental counseling after prenatal and perinatal diagnosis.

STUDY DESIGN

A dataset comprising 385 patients from the ARegPKD international registry study was analyzed for potential risk markers for dialysis during the first year of life.

RESULTS

Thirty-six out of 385 children (9.4%) commenced dialysis in the first year of life. According to multivariable Cox regression analysis, the presence of oligohydramnios or anhydramnios, prenatal kidney enlargement, a low Apgar score, and the need for postnatal breathing support were independently associated with an increased hazard ratio for requiring dialysis within the first year of life. The increased risk associated with Apgar score and perinatal assisted breathing was time-dependent and vanished after 5 and 8 months of life, respectively. The predicted probabilities for early dialysis varied from 1.5% (95% CI, 0.5%-4.1%) for patients with ARPKD with no prenatal sonographic abnormalities to 32.3% (95% CI, 22.2%-44.5%) in cases of documented oligohydramnios or anhydramnios, renal cysts, and enlarged kidneys.

CONCLUSIONS

This study, which identified risk factors associated with onset of dialysis in ARPKD in the first year of life, may be helpful in prenatal parental counseling in cases of suspected ARPKD.

Mid-trimester preterm premature rupture of membranes (PPROM): etiology, diagnosis, classification, international recommendations of treatment options and outcome

Mid-trimester preterm premature rupture of membranes (PPROM), defined as rupture of fetal membranes prior to 28 weeks of gestation, complicates approximately 0.4%-0.7% of all pregnancies. This condition is associated with a very high neonatal mortality rate as well as an increased risk of long- and short-term severe neonatal morbidity. The causes of the mid-trimester PPROM are multifactorial. Altered membrane morphology including marked swelling and disruption of the collagen network which is seen with PPROM can be triggered by bacterial products or/and pro-inflammatory cytokines. Activation of matrix metalloproteinases (MMP) have been implicated in the mechanism of PPROM. The propagation of bacteria is an important contributing factor not only in PPROM, but also in adverse neonatal and maternal outcomes after PPROM. Inflammatory mediators likely play a causative role in both disruption of fetal membrane integrity and activation of uterine contraction. The "classic PPROM" with oligo/an-hydramnion is associated with a short latency period and worse neonatal outcome compared to similar gestational aged neonates delivered without antecedent PPROM. The "high PPROM" syndrome is defined as a defect of the chorio-amniotic membranes, which is not located over the internal cervical os. It may be associated with either a normal or reduced amount of amniotic fluid. It may explain why sensitive biochemical tests such as the Amniosure (PAMG-1) or IGFBP-1/alpha fetoprotein test can have a positive result without other signs of overt ROM such as fluid leakage with Valsalva. The membrane defect following fetoscopy also fulfils the criteria for "high PPROM" syndrome. In some cases, the rupture of only one membrane - either the chorionic or amniotic membrane, resulting in "pre-PPROM" could precede "classic PPROM" or "high PPROM". The diagnosis of PPROM is classically established by identification of nitrazine positive, fern positive watery leakage from the cervical canal observed during in specula investigation. Other more recent diagnostic tests include the vaginal swab assay for placental alpha macroglobulin-1 test or AFP and IGFBP1. In some rare cases amniocentesis and infusion of indigo carmine has been used to confirm the diagnosis of PPROM. The management of the PPROM requires balancing the potential neonatal benefits from prolongation of the pregnancy with the risk of intra-amniotic infection and its consequences for the mother and infant. Close monitoring for signs of chorioamnionitis (e.g. body temperature, CTG, CRP, leucocytes, IL-6, procalcitonine, amniotic fluid examinations) is necessary to minimize the risk of neonatal and maternal complications. In addition to delayed delivery, broad spectrum antibiotics of penicillin or cephalosporin group and/or macrolide and corticosteroids have been show to improve neonatal outcome [reducing risk of chorioamnionitis (average risk ratio (RR)=0.66), neonatal infections (RR=0.67) and abnormal ultrasound scan of neonatal brain (RR=0.67)]. The positive effect of continuous amnioinfusion through the subcutaneously implanted perinatal port system with amniotic fluid like hypo-osmotic solution in "classic PPROM" less than 28/0 weeks' gestation shows promise but must be proved in future prospective randomized studies. Systemic antibiotics administration in "pre-PPROM" without infection and hospitalization are also of questionable benefit and needs to be further evaluated in well-designed randomized prospective studies to evaluate if it is associated with any neonatal benefit as well as the relationship to possible adverse effect of antibiotics on to fetal development and neurological outcome.

Fast Temperature-Gradient COLD PCR for the enrichment of the paternally inherited SNPs in cell free fetal DNA; an application to non-invasive prenatal diagnosis of β-thalassaemia

Objective

To develop a sensitive, specific, simple, cost-effective and reproducible platform for the non-invasive prenatal detection of paternally inherited alleles for β-thalassaemia. The development of such an assay is of major significance in order to replace currently-applied invasive methods containing inherent fetal loss risks.

Methods

We present a fast Temperature-Gradient Co-amplification at Lower Denaturation Temperature Polymerase Chain Reaction (fast TG COLD PCR) methodology for the detection of the paternally-inherited fetal alleles in maternal plasma. Two single-nucleotide polymorphisms (SNPs), rs7480526 (G/T) and rs968857 (G/A) that are located on the β-globin gene cluster and exhibit a high degree of heterozygosity in the Cypriot population were selected for evaluation. Seventeen maternal plasma samples from pregnancies at risk for β-thalassemia were analysed for the selected SNPs using the novel fast TG COLD PCR assay.

Results

Using fast TG COLD PCR, the paternally inherited allele in cell free fetal DNA was correctly determined for all the 17 maternal plasma samples tested, showing full agreement with the Chorionic Villus Sampling (CVS) analysis.

Conclusions

Our findings are encouraging and demonstrate the efficiency and sensitivity of fast TG COLD PCR in detecting the minor paternally-inherited fetal alleles in maternal plasma for the development of a NIPD assay for β-thalassaemia.

Development of a High-Fidelity Simulator for Teaching Chorionic Villus Sampling

OBJECTIVE

The objective of this study was to develop a synthetic high-fidelity simulator for teaching chorionic villus sampling.

METHODS

Working with a medical sculptor, the authors developed a simulator, constructed from various synthetic rubber materials, of a gravid female pelvis, including the vulva, vagina, cervix, and a 13-week-sized uterus with a gestational sac.

RESULTS

This simulator is high fidelity and durable, and it does not require any organic materials. Maternal-fetal medicine trainees valued this educational tool.

CONCLUSION

This novel, high-fidelity simulator is an additional tool for educators involved in teaching chorionic villus sampling.

Genetic Counseling in Primary Immunodeficiency Disorders: An Emerging Experience in Egypt

BACKGROUND

Primary immunodeficiency disorders (PIDs) are a heterogeneous group of diseases of the immune system leading to life-threatening infections, and, unless urgently treated with immune reconstitution, patients do not usually survive. With the continuing progress in molecular diagnosis, many mutations have been described in more than 300 genes. Genetic counseling has recently been considered an essential part of the management of PIDs. This study presents the experience of genetic counseling services in the largest PID center in Egypt, and reports on our management plan and the impact of prenatal diagnosis (PND) on families.

METHODS

Based on the biochemical and molecular diagnosis of index cases, PND was offered for 10 families in 12 subsequent pregnancies. Five different genes were sequenced by Sanger sequencing in fetal samples.

RESULTS

Seven fetuses were either normal or were carriers, while five fetuses were affected and human leukocyte antigen typing was performed, seeking a suitably related donor for stem cell transplantation.

CONCLUSION

In spite of the genetic heterogeneity behind PIDs, genetic counseling should play a critical role in the management and future decisions of affected families.

Biology of human primitive erythroblasts for application in noninvasive prenatal diagnosis

OBJECTIVE

Human primitive erythroblasts produced during early embryogenesis have been found in maternal circulation at early gestation and are considered good target cells for noninvasive prenatal diagnosis. We aimed to gain a better understanding of the biology of primitive erythroblasts and maximize their potential utility for noninvasive prenatal diagnosis.

METHODS

Cells were obtained from first trimester human placental tissues. Biological properties including surface antigen composition, differentiation, proliferation, enucleation, and degeneration were studied as gestation progressed. A microdroplet culture system was developed to observe the behavior of these cells in vitro.

RESULTS

Histology showed that primitive erythroblasts undergo maturation from polychromatic to orthochromatic erythroblasts and can differentiate spontaneously in vitro. Cell surface markers and nuclear gene expression suggest that the cells do not possess stemness properties, despite being primitive in nature. They have limited proliferative activity and highly deacetylated chromatin, but a microdroplet culture system can prolong their viability under normoxic conditions. No apoptosis was seen by 11 weeks' gestation, and there was no enucleation in vitro.

CONCLUSION

These properties confirm that viable cells with intact nuclei can be obtained at very early gestation for genetic analysis.

Contemporary prenatal aneuploidy screening practice in Australia: Frequently asked questions in the cell-free DNA era

Cell-free DNA screening has quickly become established in Australia as an accurate - albeit costly - prenatal screening test for trisomy 21, 18 and 13. It is also commonly used for the detection of sex chromosome abnormalities. The increasing number of prenatal screening pathways available to women has increased the complexity of pretest counselling. Concurrent advances in diagnostic testing with the widespread use of chromosomal microarrays create further challenges for the continuing education of clinicians and health consumers. This article aims to answer common clinical questions in this rapidly evolving field and complements the recently updated Royal Australian and New Zealand College of Obstetricians and Gynaecologists Statement on Prenatal Screening for Fetal Chromosome and Genetic Conditions.

MeDIP combined with in-solution targeted enrichment followed by NGS: Inter-individual methylation variability of fetal-specific biomarkers and their implementation in a proof of concept study for NIPT

DNA methylation is the most characterized epigenetic process exhibiting stochastic variation across different tissues and individuals. In non-invasive prenatal testing (NIPT) fetal specific methylated regions can potentially be used as biomarkers for the accurate detection of fetal aneuploidies. The aim of this study was the investigation of inter-individual methylation variability of previously reported fetal-specific markers and their implementation towards the development of a novel NIPT assay for the detection of trisomies 13, 18, and 21. Methylated DNA Immunoprecipitation (MeDIP) combined with in-solution targeted enrichment followed by NGS was performed in 29 CVS and 27 female plasma samples to assess inter-individual methylation variability of 331 fetal-specific differentially methylated regions (DMRs). The same approach was implemented for the NIPT of trisomies 13, 18 and 21 using spiked-in (n = 6) and pregnancy samples (n = 44), including one trisomy 13, one trisomy 18 and four trisomy 21. Despite the variability of DMRs, CVS samples showed statistically significant hypermethylation (p<2e-16) compared to plasma samples. Importantly, our assay correctly classified all euploid and aneuploid cases without any false positive results (n = 44). This work provides the starting point for the development of a NIPT assay based on a robust set of fetal specific biomarkers for the detection of fetal aneuploidies. Furthermore, the assay’s targeted nature significantly reduces the analysis cost per sample while providing high read depth at regions of interest increasing significantly its accuracy.

Complex chromosomal aberrations in a fetus originating from oocytes with smooth endoplasmic reticulum (SER) aggregates

The presence of smooth endoplasmic reticulum aggregates (SERa) in the ooplasm is considered as the most severe oocyte dysmorphism due to its serious and potentially lethal outcomes in offspring. In the present case report, a couple underwent their first intracytoplasmic sperm injection (ICSI) cycle using a gonadotrophin releasing hormone (GnRH) antagonist protocol, followed by fetal ultrasound scanning and amniocentesis. SERa were observed in all oocytes retrieved. A singleton pregnancy was established. The second trimester fetal ultrasound scan revealed a female fetus with overlapping fingers in both hands, and amniocentesis was performed for the detection of chromosomal abnormalities. Comprehensive genetic analysis with the combined use of array-comparative genomic hybridization (CGH), fluoresence in situ hybridization (FISH) and conventional cytogenetics revealed a complex chromosome rearrangement (CCR) involving three break points on two chromosomes, resulting in a reciprocal translocation with a cryptic 2q31 deletion. A week following amniocentesis, there was rupture of amniotic membranes and a stillborn was delivered. This is the first case in the literature to report a CCR with concomitant 2q31 deletion resulting in a well-defined and clinically recognizable contiguous gene syndrome with an abnormal phenotype in a fetus arising from a cohort of oocytes affected by SERa. It is suggested that fertilization and transfer of oocytes with SERa should be avoided, until further research establishes whether there is a causal relationship between the presence of SERa and chromosomal abnormalities in the resulting fetus.

ABBREVIATIONS

SER: smooth endoplasmic reticulum; ICSI: intracytoplasmic sperm injection; GnRH: gonadotrophin releasing hormone; CGH: comparative genomic hybridization; FISH: fluoresence in situ hybridization; FSH: follicle stimulating hormone; hCG: human chorionic gonadotrophin; OHSS: ovarian hyperstimulation syndrome; IVF: in vitro fertilization; MII: metaphase II; GV: germinal vesicle; CCR: complex chromosome rearrangement.

Prenatal Correction of X-Linked Hypohidrotic Ectodermal Dysplasia

Genetic deficiency of ectodysplasin A (EDA) causes X-linked hypohidrotic ectodermal dysplasia (XLHED), in which the development of sweat glands is irreversibly impaired, an condition that can lead to life-threatening hyperthermia. We observed normal development of mouse fetuses with Eda mutations after they had been exposed in utero to a recombinant protein that includes the receptor-binding domain of EDA. We administered this protein intraamniotically to two affected human twins at gestational weeks 26 and 31 and to a single affected human fetus at gestational week 26; the infants, born in week 33 (twins) and week 39 (singleton), were able to sweat normally, and XLHED-related illness had not developed by 14 to 22 months of age. (Funded by Edimer Pharmaceuticals and others.).

Frequency of submicroscopic chromosomal aberrations in pregnancies without increased risk for structural chromosomal aberrations: systematic review and meta-analysis

OBJECTIVE

To establish, based on a systematic literature review, the frequency of pathogenic submicroscopic chromosomal aberrations in fetuses that are not at increased risk for unbalanced structural chromosomal aberrations, with the aim of determining whether high-resolution testing for submicroscopic aberrations is beneficial in a general pregnant population.

METHODS

EMBASE, PubMed, Web of Science and CENTRAL databases were searched systematically on 3 June 2016 for all relevant articles on the prevalence of pathogenic submicroscopic copy number variants (CNVs) in fetuses referred for prenatal invasive testing because of advanced maternal age (AMA) or parental anxiety (ANX). Relevant full-text articles were analyzed and the prevalence of submicroscopic CNVs was calculated based on the extracted data. Meta-analysis was conducted in a pooled cohort of 10 614 fetuses based on the 10 largest studies (n > 300) of a total of 19 that were relevant.

RESULTS

Pooled estimate analysis indicated that 0.84% (95% CI, 0.55-1.30%) of fetuses that had invasive testing because of AMA/ANX carried a pathogenic clinically significant submicroscopic aberration. The onset/penetrance of submicroscopic findings was studied in 10 314 fetuses reported in eight papers that presented aberrant cases with all necessary details to allow assessment of the findings. The pooled estimates resulting from meta-analysis of the data indicated that an early-onset syndromic disorder was detected in 0.37% (95% CI, 0.27-0.52%) of cases, a susceptibility CNV was found in 0.30% (95% CI, 0.14-0.67%) and late-onset diseases were reported in 0.11% (95% CI, 0.05%-0.21%). The prevalence of early-onset syndromic disorders caused by a submicroscopic aberration was calculated to be 1:270. When the risk for submicroscopic aberrations is added to the individual risk for microscopic chromosomal aberrations, all pregnant women have a risk of higher than 1 in 180 for a relevant chromosomal aberration, and pregnant women under 36 years of age have a higher risk for submicroscopic pathogenic aberrations than for Down syndrome.

CONCLUSION

This systematic review shows that a significant proportion of fetuses in a general pregnant population carry a submicroscopic pathogenic CNV. Based on these figures, all women should be informed on their individual risk for all pathogenic chromosomal aberrations and not only for common trisomies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

A retrospective exploratory study of fetal genetic invasive procedures at a University Hospital

This is a retrospective analysis of the patient demographics and cytogenetic results of patients who underwent prenatal invasive testing for genetic analysis at the Foetal Medicine Division of the Department of Obstetrics and Gynecology, Sri Ramachandra Medical College and Research Institute. The main objective of this study was to characterise the changing trends in indications of pregnant women for foetal karyotyping in a 7-year period. A total of 257 procedures were performed in this period, and there was a significant change in the trend of indications for invasive prenatal diagnosis from an advanced maternal age in 2009 to a positive screen test by 2014. Chromosome abnormalities were observed in 9.8% of the cases, with trisomy 21 being the most frequent finding. The findings demonstrate the changing trends in screening and diagnostic testing in the tertiary care centre, with an acceptance of the first and second trimester maternal serum screening tests as a determinant for high-risk pregnancies. Impact statement What is already known on this subject? Despite the fact that India has one of the world's highest birth rates, there is still no public health care policy for the application of cytogenetic prenatal diagnosis. Nevertheless, we have been offering this test in our university teaching hospital since 2008, allowing us to characterise the changing trends in indications of pregnant women who sought invasive diagnostic procedures for foetal genetic studies. What do the results of this study add? The results of our study show that there were major changes in the common indications for prenatal diagnosis during the study period. In 2009, the main indication was an advanced maternal age, referred to in 31% of the cases, which declined steadily to 5% by 2014. In 2014, 51% of cases opted for a prenatal diagnosis because of a first trimester screen positive result, increasing from 12% in 2009. What are the implications of these findings for clinical practice and/or further research? This data is relevant as it would encourage other tertiary hospitals in developing countries like India to consider extending first trimester screening for all women, regardless of age and educate them on the options of prenatal genetic diagnosis for reassurance.

A Paradigm Shift: Considerations in Prenatal Cell-Free DNA Screening

BACKGROUND

Testing to determine the health of a fetus has undergone multiple iterations since the widespread adoption of amniocentesis in the 1970s, including several combinations of ultrasound and/or maternal serum screening. The clinical paradigm for prenatal screening for fetal chromosome aneuploidies was transformed by the introduction of cell-free DNA (cfDNA) screening or noninvasive prenatal screening in 2011.

CONTENT

The clinical performance of cfDNA screening is well-established for the most common autosomal and sex chromosome aneuploidies with a detection rate exceeding 90% for all aneuploidies. One of the most significant advantages of cfDNA screening relative to maternal serum screening is the markedly reduced false-positive rate, which is <0.5%. The clinical implementation of cfDNA screening is discussed at length, including key biological, preanalytical, and analytical factors that affect test performance.

SUMMARY

cfDNA prenatal screening for whole chromosome aneuploidies has become routine in high-risk obstetric populations. There is tremendous interest in expanding cfDNA screening to the general obstetric population. Early studies suggest that routine application of cfDNA screening is both feasible and effective, although significant economic and quality control considerations remain.

Maternal and fetal cytomegalovirus infection: diagnosis, management, and prevention

Congenital cytomegalovirus infection is a major cause of central nervous system and sensory impairments that affect cognition, motor function, hearing, language development, vestibular function, and vision. Although the importance of congenital cytomegalovirus infection is readily evident, the vast majority of maternal and fetal infections are not identified, even in developed countries. Multiple studies of prenatal cytomegalovirus infections have produced a body of knowledge that can inform the clinical approach to suspected or proven maternal and fetal infection. Reliable diagnosis of cytomegalovirus infection during pregnancy and accurate diagnosis of fetal infection are a reality. Approaches to preventing the transmission of cytomegalovirus from mother to fetus and to the treatment of fetal infection are being studied. There is evidence that public health approaches based on hygiene can dramatically reduce the rate of primary maternal cytomegalovirus infections during pregnancy. This review will consider the epidemiology of congenital cytomegalovirus infection, the diagnosis and management of primary infection during pregnancy, and approaches to preventing maternal infection.

From Prenatal to Preimplantation Genetic Diagnosis of β-Thalassemia. Prevention Model in 8748 Cases: 40 Years of Single Center Experience

The incidence of β-thalassemia in Sardinia is high and β-39 is the most common mutation. The prevention campaign started in 1977 and was performed in a single center (Microcitemico Hospital, Cagliari, Sardinia, Italy). It was based on educational programs, population screening by hematological and molecular identification of the carriers. Prenatal and pre-implantation diagnosis was offered to couples at risk. 8564 fetal diagnosis procedures using different invasive approaches and analysis techniques were performed in the last 40 years. Trans-abdominal chorionic villous sampling was preferred due to lower complication risks and early diagnosis. Chorionic villous DNA was analyzed by PCR technique. 2138 fetuses affected by β-thalassemia were diagnosed. Women opted for termination of the pregnancy (TOP) in 98.2% of these cases. Pre-implantation genetic diagnosis (PGD) was proposed to couples at risk to avoid TOP. A total of 184 PGD were performed. Initially, the procedure was exclusively offered to infertile couples, according to the law in force. The success rate of pregnancies increased from 11.1% to 30.8% when, crucial law changes were enacted, and PGD was offered to fertile women as well. Forty years of β-thalassemia prevention programs in Sardinia have demonstrated the important decrease of this severe genetic disorder.

[What are the real purpose and scope of screening for aneuploidy?]

In France, the recommended method for Down syndrome screening is the first trimester combined test, the risk assessment, based on maternal age, ultrasound measurement of fetal nuchal translucency and maternal serum markers (free β-hCG and PAPP-A). The Down syndrome detection rate is 78.7% at a screen positive rate of 5%. However, the best screening test is the integrated test using a combination of first trimester combined test and second trimester quadruple test (serum α-fetoprotein, human chorionic gonadotropin, unconjugated E₃, and dimeric inhibin-A) and being able to achieve a detection rate for Down syndrome of approximately 96% at a screen-positive rate of 5%. In recent years, the isolation of small fragments of "fetal" cell-free DNA in the maternal blood dramatically changed the screening strategy paradigm allowing a Down syndrome detection rate and false positive rate of 99.2 and 0.09%, respectively. However, aneuploidy screening based on cell-free DNA presents two major limitations which must be taken into account because they considerably limit its benefit: (i) not every woman will receive an interpretable result and that those who fail to receive a result are at increased risk for fetal aneuploidy: whether an inconclusive result is treated as screen positive or screen negative affects the overall detection rate (sensitivity) and false-positive rate (specificity) of the test; (ii) the limited number of targeted aneuploidies (trisomies 21, 18, 13 and common sex chromosome aneuploidies) in contrast to conventional noninvasive screening which is also able to detect rare aneuploidies, duplications, deletions, and other structural rearrangements. Of course, genetic counseling has to include a discussion about benefits and limitations of aneuploidy screening based on cell-free DNA. However, it should not be considered as a new screening test to substitute for conventional noninvasive screening. Moreover, if the ultimate goal is to deliver the most information about potential risk of various chromosomal abnormalities associated with adverse perinatal outcomes, then current cell-free DNA screening strategies may not be the best approach. These data highlight the limitations of cell-free DNA screening and the importance of a clear and fair information during pretest genetic counseling about benefits and limitations of any prenatal noninvasive screening (whether conventional or by cell-free DNA), but also about risks and benefits of invasive diagnostic procedures (in first- or second-line), especially since the cytogenetic analysis with chromosomal microarray analysis has improved the detection of genome microdeletions and microduplications (variants of the copy number) that can not be detected by standard cytogenetic analysis.

Noninvasive Prenatal Diagnosis of Single-Gene Disorders by Use of Droplet Digital PCR

BACKGROUND

Prenatal diagnosis in pregnancies at risk of single-gene disorders is currently performed using invasive methods such as chorionic villus sampling and amniocentesis. This is in contrast with screening for common aneuploidies, for which noninvasive methods with a single maternal blood sample have become standard clinical practice.

METHODS

We developed a protocol for noninvasive prenatal diagnosis of inherited single-gene disorders using droplet digital PCR from circulating cell-free DNA (cfDNA) in maternal plasma. First, the amount of cfDNA and fetal fraction is determined using a panel of TaqMan assays targeting high-variability single-nucleotide polymorphisms. Second, the ratio of healthy and diseased alleles in maternal plasma is quantified using TaqMan assays targeting the mutations carried by the parents. Two validation approaches of the mutation assay are presented.

RESULTS

We collected blood samples from 9 pregnancies at risk for different single-gene disorders, including common conditions and rare metabolic disorders. We measured cases at risk of hemophilia, ornithine transcarbamylase deficiency, cystic fibrosis, β-thalassemia, mevalonate kinase deficiency, acetylcholine receptor deficiency, and DFNB1 nonsyndromic hearing loss. We correctly differentiated affected and unaffected pregnancies (2 affected, 7 unaffected), confirmed by neonatal testing. We successfully measured an affected pregnancy as early as week 11 and with a fetal fraction as low as 3.7% (0.3).

CONCLUSIONS

Our method detects single-nucleotide mutations of autosomal recessive diseases as early as the first trimester of pregnancy. This is of importance for metabolic disorders in which early diagnosis can affect management of the disease and reduce complications and anxiety related to invasive testing.

Prenatal diagnosis and socioeconomic status in the non-invasive prenatal testing era: A population-based study

BACKGROUND

Advances in technology can bring great benefits to human health, but their implementation may be influenced by socioeconomic factors, particularly in the field of prenatal screening for Down syndrome.

AIM

To analyse screening test indications for, and diagnostic yield of, invasive prenatal diagnostic testing (PNDx) according to socioeconomic status.

METHODS

Retrospective analysis of population-based data on PNDx and karyotype results for 2014-2015 in the Australian state of Victoria. Women having PNDx < 25 weeks due to combined first trimester screening (CFTS), second trimester serum screening (STSS), or noninvasive prenatal testing (NIPT) results were included. PNDx data were analysed by indication and maternal Index of Relative Socio-economic Advantage and Disadvantage (IRSAD), the latter determined by postcode.

RESULTS

There were 145 206 births in 2014-2015; 1906 women underwent PNDx for the indication of CFTS (70.1%), NIPT (17.8%) or STSS (12.0%). Covariates positively associated with NIPT-indicated PNDx, compared with CFTS-indicated testing, were residence in a region of socioeconomic advantage, metropolitan status and maternal age. Women from the most advantaged regions had higher adjusted odds ratios (aOR) of NIPT-indicated testing compared with women from disadvantaged regions (aOR 5.72, 95% CI: 2.95-11.09). The diagnostic yield of PNDx increased with socioeconomic region, from 14% in the lowest IRSAD quintile to 31.2% in the highest (P < 0.0001).

CONCLUSION

Population-based data reveal significant disparities in screening indications for PNDx and hence, in diagnostic yield, according to socioeconomic region. This finding may have ethical and policy implications for prenatal screening in Australia.

Older mothers and increased impact of prenatal screening: stable livebirth prevalence of trisomy 21 in the Netherlands for the period 2000-2013

In the Netherlands, there is no registry system regarding the livebirth prevalence of trisomy 21 (T21). In 2007, a national screening programme was introduced for all pregnant women, which may have changed the livebirth prevalence of T21. The aim of this study is to analyse trends in factors that influence livebirth prevalence of T21 and to estimate the livebirth prevalence of T21 for the period of 2000–2013. National data sets were used on the following: (1) livebirths according to maternal age and (2) prenatal testing and termination of pregnancy (ToP) following diagnosis of T21. These data are combined in a model that uses maternal age-specific risk on T21 and correction factors for natural foetal loss to assess livebirth prevalence of T21. The proportion of mothers aged ≥ 36 years has increased from 12.2% in 2000 to 16.6% in 2009, to gradually decrease afterwards to 15.2% in 2013. The number of invasive tests performed adjusted for total livebirths decreased (5.9% in 2000 vs. 3.2% in 2013) with 0.18% a year (95% CI: −0.21 to −0.15; p   < 0.001). Following invasive testing, a higher proportion of foetuses was diagnosed with T21 (1.6% in 2000 vs. 4.8% in 2013) with a significant increase of 0.22% a year (95% CI: 0.18–0.26; p < 0.001). The proportion of ToP subsequent to T21 diagnosis was on average 85.7%, with no clear time trend. This resulted in a stable T21 livebirth prevalence of 13.6 per 10,000 livebirths (regression coefficient −0.025 (95% CI: −0.126 to 0.77; p = 0.60).

[Overview of feelings and practices of gynecologists and obstetricians for the noninvasive prenatal testing in France]

OBJECTIVES

To evaluate the feelings and practices of French obstetrician-gynecologists in prescribing the noninvasive prenatal testing (NIPT) before the release of the French High Authority of Health recommendations.

METHODS

Descriptive, declarative and transversal study, analyzing the feelings and practices of obstetrician-gynecologists, members of the French College of Gynecologists and Obstetricians (CNGOF) between February and May 2017 using an online questionnaire. Practitioners' feedback was self-assessed for several clinical situations using a numerical scale ranging from 1 to 10. This experience was rated as "good" (grades 6 to 10) or "bad" (grades 1-5).

RESULTS

Overall, 529 practitioners (29.2%) of 1812 CNGOF members, answered the online questionnaire. A "good" feeling was found for more than 65% of the practitioners audited. Feelings were significantly better for obstetricians, sonographers (P<0.05) and CPDPN members (P=0.003) compared to other practitioners. Situations where the DPNI was proposed "systematically" were risks greater than 1/250 (70.9%), between 1/250 and 1/500 (59.4%), greater than 1/250 associated with history of spontaneous miscarriages and/or fetal death in utero (66%), greater than 1/250 associated with pregnancy resulting from PMA (68.3%), history of fetal aneuploidy (54%) and a parent carrying a Robertsonian translocation (51.6%).

CONCLUSION

This study highlights a good overall feeling of the practitioners with the NIPT.

A Potential Diagnostic Approach for Foetal Long-QT Syndrome, Developed and Validated in Children

In patients with Long-QT Syndrome (LQTS), mechanical abnormalities have been described. Recognition of these abnormalities could potentially be used in the diagnosis of LQTS, especially in the foetus where an ECG is not available and DNA-analysis is invasive. We aimed to develop and validate a marker for these mechanical abnormalities in children and to test its feasibility in foetuses as a proof of principle. We measured the myocardial contraction duration using colour Tissue Doppler Imaging (cTDI) in 41 LQTS children and age- and gender-matched controls. Children were chosen to develop and validate the measurement of the myocardial contraction duration, due to the availability of a simultaneously recorded ECG. Feasibility of this measurement in foetuses was tested in an additional pilot study among seven LQTS foetuses and eight controls. LQTS children had a longer myocardial contraction duration compared to controls, while there was no statistical difference in heart rate. Measuring the myocardial contraction duration in children had a high inter- and intra-observer validity and reliably correlated with the QT-interval. There was an area under the curve (AUC) of 0.71, and the optimal cut-off value showed an especially high specificity in diagnosing LQTS. Measuring the myocardial contraction duration was possible in all foetuses and had a high inter- and intra-observer validity (ICC = 0.71 and ICC = 0.88, respectively). LQTS foetuses seemed to have a longer myocardial contraction duration compared to controls. Therefore, a prolonged contraction duration may be a potential marker for the prenatal diagnosis of LQTS in the future. Further studies are required to support the measurement of the myocardial contraction duration as a diagnostic approach for foetal LQTS.