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

Genomics-based non-invasive prenatal testing for detection of fetal chromosomal aneuploidy in pregnant women

BACKGROUND

Common fetal aneuploidies include Down syndrome (trisomy 21 or T21), Edward syndrome (trisomy 18 or T18), Patau syndrome (trisomy 13 or T13), Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Triple X syndrome (47,XXX) and 47,XYY syndrome (47,XYY). Prenatal screening for fetal aneuploidies is standard care in many countries, but current biochemical and ultrasound tests have high false negative and false positive rates. The discovery of fetal circulating cell-free DNA (ccfDNA) in maternal blood offers the potential for genomics-based non-invasive prenatal testing (gNIPT) as a more accurate screening method. Two approaches used for gNIPT are massively parallel shotgun sequencing (MPSS) and targeted massively parallel sequencing (TMPS).

OBJECTIVES

To evaluate and compare the diagnostic accuracy of MPSS and TMPS for gNIPT as a first-tier test in unselected populations of pregnant women undergoing aneuploidy screening or as a second-tier test in pregnant women considered to be high risk after first-tier screening for common fetal aneuploidies. The gNIPT results were confirmed by a reference standard such as fetal karyotype or neonatal clinical examination.

SEARCH METHODS

We searched 13 databases (including MEDLINE, Embase and Web of Science) from 1 January 2007 to 12 July 2016 without any language, search filter or publication type restrictions. We also screened reference lists of relevant full-text articles, websites of private prenatal diagnosis companies and conference abstracts.

SELECTION CRITERIA

Studies could include pregnant women of any age, ethnicity and gestational age with singleton or multifetal pregnancy. The women must have had a screening test for fetal aneuploidy by MPSS or TMPS and a reference standard such as fetal karyotype or medical records from birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently carried out study selection, data extraction and quality assessment (using the QUADAS-2 tool). Where possible, hierarchical models or simpler alternatives were used for meta-analysis.

MAIN RESULTS

Sixty-five studies of 86,139 pregnant women (3141 aneuploids and 82,998 euploids) were included. No study was judged to be at low risk of bias across the four domains of the QUADAS-2 tool but applicability concerns were generally low. Of the 65 studies, 42 enrolled pregnant women at high risk, five recruited an unselected population and 18 recruited cohorts with a mix of prior risk of fetal aneuploidy. Among the 65 studies, 44 evaluated MPSS and 21 evaluated TMPS; of these, five studies also compared gNIPT with a traditional screening test (biochemical, ultrasound or both). Forty-six out of 65 studies (71%) reported gNIPT assay failure rate, which ranged between 0% and 25% for MPSS, and between 0.8% and 7.5% for TMPS.In the population of unselected pregnant women, MPSS was evaluated by only one study; the study assessed T21, T18 and T13. TMPS was assessed for T21 in four studies involving unselected cohorts; three of the studies also assessed T18 and 13. In pooled analyses (88 T21 cases, 22 T18 cases, eight T13 cases and 20,649 unaffected pregnancies (non T21, T18 and T13)), the clinical sensitivity (95% confidence interval (CI)) of TMPS was 99.2% (78.2% to 100%), 90.9% (70.0% to 97.7%) and 65.1% (9.16% to 97.2%) for T21, T18 and T13, respectively. The corresponding clinical specificity was above 99.9% for T21, T18 and T13.In high-risk populations, MPSS was assessed for T21, T18, T13 and 45,X in 30, 28, 20 and 12 studies, respectively. In pooled analyses (1048 T21 cases, 332 T18 cases, 128 T13 cases and 15,797 unaffected pregnancies), the clinical sensitivity (95% confidence interval (CI)) of MPSS was 99.7% (98.0% to 100%), 97.8% (92.5% to 99.4%), 95.8% (86.1% to 98.9%) and 91.7% (78.3% to 97.1%) for T21, T18, T13 and 45,X, respectively. The corresponding clinical specificities (95% CI) were 99.9% (99.8% to 100%), 99.9% (99.8% to 100%), 99.8% (99.8% to 99.9%) and 99.6% (98.9% to 99.8%). In this risk group, TMPS was assessed for T21, T18, T13 and 45,X in six, five, two and four studies. In pooled analyses (246 T21 cases, 112 T18 cases, 20 T13 cases and 4282 unaffected pregnancies), the clinical sensitivity (95% CI) of TMPS was 99.2% (96.8% to 99.8%), 98.2% (93.1% to 99.6%), 100% (83.9% to 100%) and 92.4% (84.1% to 96.5%) for T21, T18, T13 and 45,X respectively. The clinical specificities were above 100% for T21, T18 and T13 and 99.8% (98.3% to 100%) for 45,X. Indirect comparisons of MPSS and TMPS for T21, T18 and 45,X showed no statistical difference in clinical sensitivity, clinical specificity or both. Due to limited data, comparative meta-analysis of MPSS and TMPS was not possible for T13.We were unable to perform meta-analyses of gNIPT for 47,XXX, 47,XXY and 47,XYY because there were very few or no studies in one or more risk groups.

AUTHORS' CONCLUSIONS

These results show that MPSS and TMPS perform similarly in terms of clinical sensitivity and specificity for the detection of fetal T31, T18, T13 and sex chromosome aneuploidy (SCA). However, no study compared the two approaches head-to-head in the same cohort of patients. The accuracy of gNIPT as a prenatal screening test has been mainly evaluated as a second-tier screening test to identify pregnancies at very low risk of fetal aneuploidies (T21, T18 and T13), thus avoiding invasive procedures. Genomics-based non-invasive prenatal testing methods appear to be sensitive and highly specific for detection of fetal trisomies 21, 18 and 13 in high-risk populations. There is paucity of data on the accuracy of gNIPT as a first-tier aneuploidy screening test in a population of unselected pregnant women. With respect to the replacement of invasive tests, the performance of gNIPT observed in this review is not sufficient to replace current invasive diagnostic tests.We conclude that given the current data on the performance of gNIPT, invasive fetal karyotyping is still the required diagnostic approach to confirm the presence of a chromosomal abnormality prior to making irreversible decisions relative to the pregnancy outcome. However, most of the gNIPT studies were prone to bias, especially in terms of the selection of participants.

Challenges in non-invasive prenatal screening for sub-chromosomal copy number variations using cell-free DNA

Non-invasive prenatal screening (NIPS) has revolutionized the approach to prenatal fetal aneuploidy screening. Many commercial providers now offer analyses for sub-chromosomal copy number variations (CNVs). Here, we review the use of NIPS in the context of screening for microdeletions and microduplications, issues surrounding the choice of disorders tested for, and the advantages and disadvantages associated with the inclusion of microdeletions to current NIPS. Several studies have claimed benefits; however, we suggest that microdeletions have not demonstrated a low enough false positive rate to be deemed practical or ethically acceptable, especially considering their low positive predictive values. Because a positive NIPS result should be confirmed using diagnostic techniques, and false positive rates are as high as 90% for some microdeletions, diagnostic testing seems preferable when the goal is to maximize the detection of microdeletion or microduplication syndromes.

What's New in Prenatal Genetics? A Review of Current Recommendations and Guidelines

Importance

The rapid development of prenatal genetic testing and screening tools and choices constantly challenges clinicians to stay up to date on current best practice.

Objective

We sought to review, compare, and summarize recent national society guidelines on prepregnancy genetic screening and prenatal diagnosis for aneuploidy with a focus on changes and additions to previous guidelines.

Evidence Acquisition

We performed a descriptive review of 8 recently published (2016-2017) national guidelines and updates on prenatal genetic screening and testing including American Congress of Obstetricians and Gynecologists committee opinions and practice bulletins, Society for Maternal-Fetal Medicine consult series publications, and an American College of Medical Genetics and Genomics position statement. Topics included carrier screening, cell-free DNA screening, chromosomal microarray analysis, next-generation sequencing, and prenatal diagnostic testing. The recommendations in these publications were compared, and the additions and changes to previous recommendations and guidelines were summarized.

Results

Recent publications contain many updates and changes to previous screening and testing strategies, most of which are consistent between professional societies. Although many new technologies have been integrated into prenatal diagnosis, some newer technologies are not yet routinely recommended for widespread use, often because of lack of clinical trials and validation studies.

Conclusions

Prenatal screening and testing options are rapidly expanding. To provide best-practice prenatal care, obstetric care providers should educate themselves about the most up-to-date recommendations and be prepared to interpret and apply these guidelines to their patients. Society guidelines are largely in agreement.

Implementing non-invasive prenatal testing into publicly funded antenatal screening services for Down syndrome and other conditions in Aotearoa New Zealand

Background

Non-invasive prenatal testing (NIPT) is a relatively new screen for congenital conditions – specifically, common fetal aneuploidies including Down Syndrome. The test is based on isolating freely circulating fragments of fetal-placental DNA that is present in the mother’s blood. NIPT has a superior clinical performance compared to current screening, and has been available privately in Aotearoa New Zealand for the last 4 years.

Main issue

The proposed implementation of NIPT as a publicly funded service may widen the inequity in access to optional antenatal screening that already exists in this country.

Conclusion

This paper discusses precautions that can be taken at the health system, organisation, and personnel levels to ensure that access to NIPT is equitable, that services are culturally responsive, and women’s informed choice is promoted and protected. The adoption of NIPT into publicly funded services is an example of how genetic screening is becoming mainstreamed into health services; as such our approach may also have relevance around the introduction of other genetic and genomic screening initiatives.

Non-invasive prenatal testing (NIPT): Europe's first multicenter post-market clinical follow-up study validating the quality in clinical routine

PURPOSE

Non-invasive prenatal tests (NIPT) for the determination of fetal aneuploidies from maternal blood are firmly established in clinical routine. For the first time, the accuracy of an NIPT for the determination of trisomies 21, 18 and 13 in singleton pregnancies was assessed by means of a prospective German-wide multicenter post-market clinical follow-up study, to reliably evaluate the quality in clinical routine.

METHODS

The study covered the indications for testing, the test results, the rate of invasive diagnostics and the pregnancy outcome. 2232 cases were tested for trisomy 21. Of these, 1946 cases were additionally examined for trisomy 18 and 13.

RESULTS

Sensitivity and specificity for trisomy 21 (43/43) and for trisomy 13 (2/2) were 100%, for trisomy 18 the sensitivity was 80% (4/5) with a specificity of 99.8%. Three false-positive results for trisomy 18 were observed (FPR 0.15%). The no-call rate was 0.5%. In this subgroup, 27.3% (3/11) aneuploidies were diagnosed. The rate of invasive procedures was 2.6%.

CONCLUSION

NIPT provides a very high quality for the fetal trisomies 21, 13 and 18 in clinical routine. The results support the recommendation that NIPT should be offered after genetic counseling and only in conjunction with a qualified ultrasound examination.

Sensitive Monogenic Noninvasive Prenatal Diagnosis by Targeted Haplotyping

During pregnancy, cell-free DNA (cfDNA) in maternal blood encompasses a small percentage of cell-free fetal DNA (cffDNA), an easily accessible source for determination of fetal disease status in risk families through non-invasive procedures. In case of monogenic heritable disease, background maternal cfDNA prohibits direct observation of the maternally inherited allele. Non-invasive prenatal diagnostics (NIPD) of monogenic diseases therefore relies on parental haplotyping and statistical assessment of inherited alleles from cffDNA, techniques currently unavailable for routine clinical practice. Here, we present monogenic NIPD (MG-NIPD), which requires a blood sample from both parents, for targeted locus amplification (TLA)-based phasing of heterozygous variants selectively at a gene of interest. Capture probes-based targeted sequencing of cfDNA from the pregnant mother and a tailored statistical analysis enables predicting fetal gene inheritance. MG-NIPD was validated for 18 pregnancies, focusing on CFTR, CYP21A2, and HBB. In all cases we could predict the inherited alleles with >98% confidence, even at relatively early stages (8 weeks) of pregnancy. This prediction and the accuracy of parental haplotyping was confirmed by sequencing of fetal material obtained by parallel invasive procedures. MG-NIPD is a robust method that requires standard instrumentation and can be implemented in any clinic to provide families carrying a severe monogenic disease with a prenatal diagnostic test based on a simple blood draw.

Obstetric professionals' perceptions of non-invasive prenatal testing for Down syndrome: clinical usefulness compared with existing tests and ethical implications

BACKGROUND

While non-invasive prenatal testing (NIPT) for fetal aneuploidy is commercially available in many countries, little is known about how obstetric professionals in non-Western populations perceive the clinical usefulness of NIPT in comparison with existing first-trimester combined screening (FTS) for Down syndrome (DS) or invasive prenatal diagnosis (IPD), or perceptions of their ethical concerns arising from the use of NIPT.

METHODS

A cross-sectional survey among 327 obstetric professionals (237 midwives, 90 obstetricians) in Hong Kong.

RESULTS

Compared to FTS, NIPT was believed to: provide more psychological benefits and enable earlier consideration of termination of pregnancy. Compared to IPD, NIPT was believed to: provide less psychological stress for high-risk women and more psychological assurance for low-risk women, and offer an advantage to detect chromosomal abnormalities earlier. Significant differences in perceived clinical usefulness were found by profession and healthcare sector: (1) obstetricians reported more certain views towards the usefulness of NIPT than midwives and (2) professionals in the public sector perceived less usefulness of NIPT than the private sector. Beliefs about earlier detection of DS using NIPT were associated with ethical concerns about increasing abortion. Participants believing that NIPT provided psychological assurance among low-risk women were less likely to be concerned about ethical issues relating to informed decision-making and pre-test consultation for NIPT.

CONCLUSIONS

Our findings suggest the need for political debate initially on how to ensure pregnant women accessing public services are informed about commercially available more advanced technology, but also on the potential implementation of NIPT within public services to improve access and equity to DS screening services.

Amniocentesis and chorionic villus sampling for prenatal diagnosis

BACKGROUND

During pregnancy, fetal cells suitable for genetic testing can be obtained from amniotic fluid by amniocentesis (AC), placental tissue by chorionic villus sampling (CVS), or fetal blood. A major disadvantage of second trimester amniocentesis is that the results are available relatively late in pregnancy (after 16 weeks' gestation). Earlier alternatives are chorionic villus sampling (CVS) and early amniocentesis, which can be performed in the first trimester of pregnancy.

OBJECTIVES

The objective of this review was to compare the safety and accuracy of all types of AC (i.e. early and late) and CVS (e.g. transabdominal, transcervical) for prenatal diagnosis.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (3 March 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP; 3 March 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised trials comparing AC and CVS by either transabdominal or transcervical route.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included a total of 16 randomised studies, with a total of 33,555 women, 14 of which were deemed to be at low risk of bias. The number of women included in the trials ranged from 223 to 4606.Studies were categorized into six comparisons: 1. second trimester AC versus control; 2. early versus second trimester AC; 3. CVS versus second trimester AC; 4. CVS methods; 5. Early AC versus CVS; and 6. AC with or without ultrasound.One study compared second trimester AC with no AC (control) in a low risk population (women = 4606). Background pregnancy loss was around 2%. Second trimester AC compared to no testing increased total pregnancy loss by another 1%. The confidence intervals (CI) around this excess risk were relatively large (3.2% versus 2.3 %, average risk ratio (RR) 1.41, 95% CI 0.99 to 2.00; moderate-quality evidence). In the same study, spontaneous miscarriages were also higher (2.1% versus 1.3%; average RR 1.60, 95% CI 1.02 to 2.52; high-quality evidence). The number of congenital anomalies was similar in both groups (2.0% versus 2.2%, average RR 0.93, 95% CI 0.62 to 1.39; moderate-quality evidence).One study (women = 4334) found that early amniocentesis was not a safe early alternative compared to second trimester amniocentesis because of increased total pregnancy losses (7.6% versus 5.9%; average RR 1.29, 95% CI 1.03 to 1.61; high-quality evidence), spontaneous miscarriages (3.6% versus 2.5%, average RR 1.41, 95% CI 1.00 to 1.98; moderate-quality evidence), and a higher incidence of congential anomalies, including talipes (4.7% versus 2.7%; average RR 1.73, 95% CI 1.26 to 2.38; high-quality evidence).When pregnancy loss after CVS was compared with second trimester AC, there was a clinically significant heterogeneity in the size and direction of the effect depending on the technique used (transabdominal or transcervical), therefore, the results were not pooled. Only one study compared transabdominal CVS with second trimester AC (women = 2234). They found no clear difference between the two procedures in the total pregnancy loss (6.3% versus 7%; average RR 0.90, 95% CI 0.66 to 1.23, low-quality evidence), spontaneous miscarriages (3.0% versus 3.9%; average RR 0.77, 95% CI 0.49 to 1.21; low-quality evidence), and perinatal deaths (0.7% versus 0.6%; average RR 1.18, 95% CI 0.40 to 3.51; low-quality evidence). Transcervical CVS may carry a higher risk of pregnancy loss (14.5% versus 11.5%; average RR 1.40, 95% CI 1.09 to 1.81), but the results were quite heterogeneous.Five studies compared transabdominal and transcervical CVS (women = 7978). There were no clear differences between the two methods in pregnancy losses (average RR 1.16, 95% CI 0.81 to 1.65; very low-quality evidence), spontaneous miscarriages (average RR 1.68, 95% CI 0.79 to 3.58; very low-quality evidence), or anomalies (average RR 0.68, 95% CI 0.41 to 1.12; low-quality evidence). We downgraded the quality of the evidence to low due to heterogeneity between studies. Transcervical CVS may be more technically demanding than transabdominal CVS, with more failures to obtain sample (2.0% versus 1.1%; average RR 1.79, 95% CI 1.13 to 2.82, moderate-quality evidence).Overall, we found low-quality evidence for outcomes when early amniocentesis was compared to transabdominal CVS. Spontaneous miscarriage was the only outcome supported by moderate-quality evidence, resulting in more miscarriages after early AC compared with transabdominal CVS (2.3% versus 1.3%; average RR 1.73, 95% CI 1.15 to 2.60). There were no clear differences in pregnancy losses (average RR 1.15, 95% CI 0.86 to 1.54; low-quality evidence), or anomalies (average RR 1.14, 95% CI 0.57 to 2.30; very low-quality evidence).We found one study that examined AC with or without ultrasound, which evaluated a type of ultrasound-assisted procedure that is now considered obsolete.

AUTHORS' CONCLUSIONS

Second trimester amniocentesis increased the risk of pregnancy loss, but it was not possible to quantify this increase precisely from only one study, carried out more than 30 years ago.Early amniocentesis was not as safe as second trimester amniocentesis, illustrated by increased pregnancy loss and congenital anomalies (talipes). Transcervical chorionic villus sampling compared with second trimester amniocentesis may be associated with a higher risk of pregnancy loss, but results were quite heterogeneous.Diagnostic accuracy of different methods could not be assessed adequately because of incomplete karyotype data in most studies.

Down Syndrome Screening in India: Are We There Yet?

Down syndrome is the most common cause of intellectual disability among live born children and is amenable to prenatal detection. Screening for Down syndrome on a population basis requires a thorough understanding of the principles involved in the screening tests. We discuss the rationale behind the commonly available screening tests and the Indian scenario in this setting.

Cell-Free DNA-Based Non-invasive Prenatal Screening for Common Aneuploidies in a Canadian Province: A Cost-Effectiveness Analysis

OBJECTIVE

Yearly, 450 000 pregnant Canadians are eligible for voluntary prenatal screening for trisomy 21. Different screening strategies select approximately 4% of women for invasive fetal chromosome testing. Non-invasive prenatal testing (NIPT) using maternal blood cell-free DNA could reduce those invasive procedures but is expensive. This study evaluated the cost-effectiveness of NIPT strategies compared with conventional strategies.

METHODS

This study used a decision analytic model to estimate the cost-effectiveness of 13 prenatal screening strategies for fetal aneuploidies: six frequently used strategies, universal NIPT, and six strategies incorporating NIPT as a second-tier test. The study considered a virtual cohort of pregnant women of similar size and age as women in Quebec. Model data were obtained from published sources and government databases. The study predicted the number of chromosomal anomalies detected (trisomies 21, 13, and 18), invasive procedures and euploid fetal losses, direct costs, and incremental cost-effectiveness ratios.

RESULTS

Of the 13 strategies compared, eight identified fewer cases at a higher cost than at least one of the remaining five strategies. Integrated serum screening with conditional NIPT had the lowest cost, and the cost per case detected was $63 139, with a 90% reduction of invasive procedures. The number of cases identified was improved with four other screening strategies, but with increasing of incremental costs per case (from $61 623 to $1 553 615). Results remained robust, except when NIPT costs and risk cut-offs varied.

CONCLUSION

NIPT as a second-tier test for high-risk women is likely to be cost-effective as compared with screening algorithms not involving NIPT.

[Fetal autopsies : Relic or still a gold standard?]

BACKGROUND

Fetal autopsy rates are decreasing in Western countries although post-mortem examinations render important information for the parents concerning the cause of abortion and risk of recurrence in future pregnancies.

OBJECTIVE

The intention of the presented study was to analyze the development of fetal autopsies in Germany during the last decade and to review accessible information obtained by fetal autopsy.

MATERIAL AND METHODS

Reports of fetal autopsies conducted in two German university Institutes of pathology between 2005 and 2014 were evaluated retrospectively. Demographic data and the correlation between clinical diagnoses and autopsy findings were assessed. In addition, differences between spontaneous and induced cases of abortion and differences between the institutes were also documented.

RESULTS

Overall, 428 fetal autopsies were performed, whereby the number of autopsies decreased by 24.2% during the study period. Of the examined fetuses 29.7% were induced abortions which as expected exhibited different malformations compared to cases of spontaneous abortion (p < 0.001). There was no evidence of a malformation or other cause of death in 27.1% of the cases and 95.7% of these abortions occurred spontaneously. A discrepancy between clinical and autopsy findings was evident in 6.8% of cases and 3.5% of the autopsy examinations revealed at least one additional malformation compared to the prenatal clinical data.

CONCLUSION

Despite improvements in prenatal diagnostics, fetal autopsies remain an important diagnostic tool even today contributing additional information in a considerable number of cases potentially revising clinical diagnoses.

Summary of 2185 prenatal invasive procedures in a single center: A retrospective analysis

Objective:

To determine the frequency, indications, and outcomes of diagnostic invasive prenatal procedures (DIPP) performed in a university hospital.

Materials and Methods:

This retrospective, observational study included 2185 cases of DIPP (chorionic villus sampling, amniocentesis, and cordocentesis) performed at the department of obstetrics and gynecology of a university hospital between 2010 and 2016. We included all DIPP cases performed between 11 and 24 weeks of gestation. We compared the different types of DIPP performed in our hospital.

Results:

Two thousand one hundred eighty-five procedures were performed (1853 amniocenteses, 326 chorionic villus sampling, and 6 cordocenteses). The main indication for performing invasive procedures was abnormal results of aneuploidy screening for trisomy 21, followed by maternal age, and fetal structural abnormality. The fetal karyotype was altered in 154 (26.1%) cases. Trisomy 21 was the most common aneuploidy followed by trisomy 18, monosomy X, and trisomy 13. Fetal karyotype could not be revealed in 42 (2%) cases due to maternal contamination in 18 cases, inadequate sampling in 4 cases, and failure of cell culture in 27 cases. There were 2 pregnancy losses due to the invasive procedure (only in amniocentesis).

Conclusion:

The ideal approach to pregnancies with a detected chromosomal abnormality should be tailored according to the individual choice of the couples regarding whether they decide for or against a child with a known chromosomal abnormality.

Prenatal Diagnosis: Screening and Diagnostic Tools

The American Congress of Obstetricians and Gynecologists recommends that all pregnant women be offered aneuploidy screening or diagnostic testing. A myriad of screening and testing options are available to patients based on their risk profile and gestational age. Screening options include traditional serum analyte screening, such as first-trimester screening or quadruple screening, and more recently, cell-free DNA. Diagnostic testing choices include chorionic villus sampling and amniocentesis. The number of screening and diagnostic modalities complicates prenatal counseling for physicians and can be difficult for patients to grasp. Appropriate pretest and posttest counseling is important to ensure adequate understanding of results and ensure testing strategy is concordant with patient goals.

The yield and complications of amniocentesis performed after 24 weeks of gestation

PURPOSE

This study assessed the use and complications of late amniocentesis (AC) and analyzed factors that affect complication rate.

METHODS

A retrospective analysis of 167 genetic AC performed after 24 weeks during a 10-year period in two medical centers was conducted. Data regarding the indications for AC, genetic work-up, and pregnancy outcomes were retrieved from patient medical records and telephone-based questionnaires.

RESULTS

Mean gestational age (GA) at the time of AC was 31.7 ± 2.7 weeks; 104 procedures were performed at ≤32 weeks, including 24 at ≤30 weeks. The overall pregnancy complication rate occurring at any time after the procedure was 6.6% (11). Of these, 4.8% (8) occurred within a month after AC, including 2.4% (4) that occurred within a week. An additional three occurred after 30 days. There were no differences in the total complication rate and in the rate of specific complications of procedures performed at ≤32 weeks or at ≤30 weeks. Maternal age did not affect outcomes. Genetic testing was abnormal in five cases (3%). Amniocyte culture failed in 3 cases (2.3%), with no technical failures in 52 chromosomal microarray tests.

CONCLUSION

The complication rate of AC performed after 24 weeks was 4.8%, which is significantly higher than that of second trimester AC. GA and maternal age did not affect the complication rate.

Potential clinical applications of placental stem cells for use in fetal therapy of birth defects

Placental stem cells are of growing interest for a variety of clinical applications due to their multipotency and ready availability from otherwise frequently discarded biomaterial. Stem cells derived from the placenta have been investigated in a number of disease processes, including wound healing, ischemic heart disease, autoimmune disorders, and chronic lung or liver injury. Fetal intervention for structural congenital defects, such as spina bifida, has rapidly progressed as a field due to advances in maternal-fetal medicine and improving surgical techniques. In utero treatment of structural, as well as non-structural, congenital disorders with cell-based therapies is of particular interest given the immunologic immaturity and immunotolerant environment of the developing fetus. A comprehensive literature review was performed to assess the potential utilization of placenta-derived stem cells for in utero treatment of congenital disorders. Most studies are still in the preclinical phase, utilizing animal models of common congenital disorders. Future research endeavors may include autologous transplantation, gene transfers, induced pluripotent stem cells, or cell-free therapies derived from the stem cell secretome. Though much work still needs to be done, placental stem cells are a promising therapeutic agent for fetal intervention for congenital disease.

Preferences for prenatal diagnosis of sickle-cell disorder: A discrete choice experiment comparing potential service users and health-care providers

Background

Non‐invasive prenatal diagnosis (NIPD) for sickle‐cell disorder (SCD) is moving closer to implementation and studies considering stakeholder preferences are required to underpin strategies for offering NIPD in clinical practice.

Objective

Determine service user and provider preferences for key attributes of prenatal diagnostic tests for SCD and examine views on NIPD.

Method

A questionnaire that includes a discrete choice experiment was used to determine the preferences of service users and providers for prenatal tests that varied across three attributes: accuracy, time of test and risk of miscarriage.

Results

Adults who were carriers of SCD or affected with the condition (N=67) were recruited from haemoglobinopathy clinics at two maternity units. Health professionals, predominately midwives, who offer antenatal care (N=62) were recruited from one maternity unit. No miscarriage risk was a key driver of decision making for both service users and providers. Service providers placed greater emphasis on accuracy than service users. Current uptake of invasive tests was 63%, whilst predicted uptake of NIPD was 93.8%. Many service users (55.4%) and providers (52.5%) think pressure to have prenatal testing will increase when NIPD for SCD becomes available.

Conclusions

There are clear differences between service users and health professionals’ preferences for prenatal tests for sickle‐cell disorder. The safety of NIPD is welcomed by parents and uptake is likely to be high. To promote informed choice, pretest counselling should be balanced and not exclusively focused on test safety. Counselling strategies that are sensitive to feelings of pressure to test will be essential.

[Training of residents in amniocentesis: Effectiveness of a craft simulator]

OBJECTIVE

This prospective study aims to assess a low fidelity simulation device for learning amniocentesis to gynecology-obstetrics residents.

METHODS

From 2013 to 2016, gynecology-obstetrics residents of all levels, from the maternity of Nancy hospital, which have already performed amniocentesis or not, participated in amniocentesis training on an artisanal simulator. Residents were evaluated on the amniocentesis simulator according to seven quality criteria. Three scores were assigned: the first (S1) at the beginning of the first training session, the second (S2) at the end of the first session after individualized personal training and the third (S3) two months after the first simulation.

RESULTS

A total of 40 residents were included. The scores obtained by the residents were 3.2±1.8 points for S1 versus 6.2±0.9 points for S2 (P<0.001). Two months after, the residents' performances remained significantly improved compared to the initial assessment with a score (S3) of 5.8±1.3 points at S3 (P<0.001).

CONCLUSION

Amniocentesis craft simulator is effective for performance improvement and allows a persistence of acquired skills two months after the training. At the time of "never the first time on the patient", it should be part of the curriculum of gynecology-obstetrics residents in order to guarantee patients quality care and optimum safety.

Total pregnancy loss after chorionic villus sampling and amniocentesis: a cohort study

OBJECTIVES

To identify maternal-, operator- and procedure-related variables that affect procedure-related pregnancy loss after transcervical (TC) and transabdominal (TA) chorionic villus sampling (CVS) and amniocentesis and to estimate the rates of spontaneous and procedure-related loss in comparable subgroups of women.

METHODS

This was a retrospective cohort study conducted at the University Medical Center Groningen and the Academic Medical Center, The Netherlands. Databases of both centers were searched to identify singleton pregnancies that had undergone a combined test and/or anomaly scan at around 20 weeks' gestation, or an invasive procedure (CVS and/or amniocentesis) between January 2001 and December 2011. Maternal characteristics, obstetric history, technical aspects of the invasive procedure, ultrasound examinations and fetal and neonatal outcomes were available for 29 201 cases. Women were categorized, according to the type of examination they had received, into the following five groups: first-trimester combined test (and 20-week anomaly scan); 20-week anomaly scan only; CVS; amniocentesis; amniocentesis after unsuccessful CVS. Rates of fetal loss were compared between groups.

RESULTS

Variables significantly associated with a higher rate of fetal loss were, for CVS, repeat attempts during the procedure, use of TC cannula instead of biopsy forceps, gestational age at procedure ≥ 13 weeks and a pregnancy after assisted reproductive techniques, and, for amniocentesis, if indication was fetal anomaly or family history of anomalies and repeat attempts during the procedure. In women aged ≥ 36 years who did not undergo an invasive procedure, spontaneous fetal loss rate (FLR) after first-trimester combined test was 1.40%, whereas after CVS, FLR was 2.76% and 2.43% for a TC and TA approach, respectively. The additional risk of fetal loss with TC-CVS was therefore 1.36% (1 : 74), which varied according to the instrument used (0.27% for forceps and 3.12% for cannula), and with TA-CVS was 1.03% (1 : 97). In women aged ≥ 36 years who underwent a 20-week anomaly scan only, spontaneous FLR was 0.63%. In women who underwent amniocentesis solely because of advanced maternal age, FLR was 1.11%. The additional risk of fetal loss with amniocentesis was 0.48% (1 : 208).

CONCLUSION

The total rate of procedure-related fetal loss after TA- and TC-CVS and amniocentesis appears lower than the risks on which women are currently counseled. There was a trend for a decrease in risk when the level of experience of the operator increased. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Development and evaluation of training resources to prepare health professionals for counselling pregnant women about non-invasive prenatal testing for Down syndrome: a mixed methods study

BACKGROUND

The availability of non-invasive prenatal testing (NIPT) for aneuploidies is expanding rapidly throughout the world. Training health professionals to offer NIPT in a way that supports informed choice is essential for implementation. The aim of this study was to develop and evaluate a training package for health professionals to support the introduction of NIPT into clinical practice.

METHODS

Training on NIPT was offered to health professionals, primarily midwives, involved in Down syndrome screening and testing in eight hospitals located in England and Scotland as part of a research study evaluating the implementation of NIPT in the UK National Health Service. Training was evaluated using a mixed methods approach that included quantitative questionnaires at three time points and post-training qualitative interviews. The questionnaires measured confidence, self-perceived knowledge and actual knowledge about NIPT for Down syndrome. Interviews explored opinions about the training and experiences of offering NIPT.

RESULTS

The training provided to the health professionals was found to positively impact on their confidence in discussing NIPT with women in their clinic, and both their perceived and actual knowledge and understanding of NIPT was improved. Knowledge remained weak in four areas; cell-free fetal DNA levels increase with gestation; turnaround time for NIPT results; cell-free fetal DNA is placental in origin; and NIPT false positive rate.

CONCLUSIONS

Training materials, including a lesson plan, PowerPoint presentation and written factsheet on NIPT, have been developed and evaluated for use in educating midwives and supporting the introduction of NIPT. Implementation of training should include a greater focus on the areas where knowledge remained low. Some groups of midwives will need additional training or support to optimise their confidence in discussing NIPT with women.

Noninvasive prenatal screening at low fetal fraction: comparing whole-genome sequencing and single-nucleotide polymorphism methods

OBJECTIVE

Performance of noninvasive prenatal screening (NIPS) methodologies when applied to low fetal fraction samples is not well established. The single-nucleotide polymorphism (SNP) method fails samples below a predetermined fetal fraction threshold, whereas some laboratories employing the whole-genome sequencing (WGS) method report aneuploidy calls for all samples. Here, the performance of the two methods was compared to determine which approach actually detects more fetal aneuploidies.

METHODS

Computational models were parameterized with up-to-date published data and used to compare the performance of the two methods at calling common fetal trisomies (T21, T18, T13) at low fetal fractions. Furthermore, clinical experience data were reviewed to determine aneuploidy detection rates based on compliance with recent invasive screening recommendations.

RESULTS

The SNP method's performance is dependent on the origin of the trisomy, and is lowest for the most common trisomies (maternal M1 nondisjunction). Consequently, the SNP method cannot maintain acceptable performance at fetal fractions below ~3%. In contrast, the WGS method maintains high specificity independent of fetal fraction and has >80% sensitivity for trisomies in low fetal fraction samples.

CONCLUSION

The WGS method will detect more aneuploidies below the fetal fraction threshold at which many labs issue a no-call result, avoiding unnecessary invasive procedures. © 2017 Counsyl Inc. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome.

SEARCH METHODS

We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies.

SELECTION CRITERIA

Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more.

AUTHORS' CONCLUSIONS

Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.

Maternal anxiety and its correlation with pain experience during chorion villus sampling and amniocentesis

PURPOSE

Invasive prenatal diagnostic procedures, such as chorion villus sampling (CVS) and amniocentesis (AC), are routinely performed to exclude or diagnose fetal chromosomal abnormalities. The aim of this study was to investigate anxiety-dependent pain experience during CVS and AC and the potential factors that increase anxiety and pain levels.

PATIENTS AND METHODS

During a 2-year period, women undergoing invasive procedures in three specialist centers were asked to participate in the study. Anxiety was evaluated before the procedure using the Spielberger State-Trait-Anxiety-Inventory, and pain was evaluated directly after the procedure using a verbal rating scale.

RESULTS

Among the women, 348/480 (73%) underwent AC, while 131/480 (27%) underwent CVS. There was a significant correlation between state and trait anxiety (p<0.0001). A positive correlation existed between the degree of anxiety and the level of pain experienced (p=0.01). There was a positive correlation for trait anxiety (p=0.0283) as well as for state anxiety (p=0.0001) and pain perception (p=0.0061) when invasive procedure was performed owing to abnormal ultrasound finding or to a history of fetal aneuploidy. Maternal age was found to be another influencing factor for the experienced pain (p=0.0016). Furthermore, the analysis showed a significant negative correlation between maternal age and anxiety. That applies for trait anxiety (p=0.0001) as well as for state anxiety (p=0.0001). The older the woman, the less anxious the reported feeling was in both groups. The main indication for undergoing CVS was abnormal ultrasound results (45%), and the main reason for undergoing AC was maternal age (58%).

CONCLUSION

Procedure-related pain intensity is highly dependent on the degree of anxiety before the invasive procedure. In addition, the indication has a significant impact on the emerging anxiety and consequential pain experiences. These influencing factors should therefore be considered during counseling and performance.

Performing and Declining PGD: Accounts of Jewish Israeli Women Who Carry a BRCA1/2 Mutation or Partners of Male Mutation Carriers

To describe factors associated with preimplantation genetic diagnosis (PGD) decisions among Jewish Israeli BRCA1/2 carriers or spouses of a male carrier, we contacted all women who initiated PGD consultation for embryonic BRCA1/2 mutation detection at Sheba Medical Center, prior to March 2014. Applying a qualitative approach, we asked women to elaborate on the factors they considered in either opting for PGD or discontinuing the screening procedure. Participants were 18 Jewish Israeli women; 14 were carriers of one of the Ashkenazi founder mutations in BRCA1/2, and four were spouses of male mutation carriers, who underwent at least one cycle of PGD. Prior to seeking PGD, ten of the women had no children. At the time of the interview, all but three had at least one child. Three factors emerged as key motivators for PGD: having witnessed the disease in a close relative (n = 12); prior IVF treatment for infertility (n = 12); and having pre-existing frozen embryos (n = 6). Ten women withdrew from the PGD process due to clinical, logistical, and financial reasons. In conclusion, most women decided to withdraw from PGD instead of continuing until a successful conception was achieved. Those who opted for PGD attributed their discontinuation of further screening to the emotional burden that is greatly intensified by practical difficulties.

Noninvasive Prenatal Testing - When Is It Advantageous to Apply

Nowadays it is common sense in obstetrics that an increased risk for pregnancy loss due to invasive testing does not exist. Nonetheless, noninvasive prenatal testing (NIPT) is a hot topic, even though this approach does not provide a reduction of unintentionally induced abortions. NIPT has a number of shortcuts which are highlighted in this review, including: (1) in NIPT placental rather than fetal DNA is studied, (2) NIPT fails in 2–6% of cases, and (3) trisomy 21 accounts for only ∼50% of existing chromosomal aberrations. Thus, we agree with the literature that NIPT is a fascinating possibility to gain information on unborn life from minimal amounts of DNA. However, it remains a pure risk estimation test directed towards the detection of specific chromosomal abnormalities from peripheral blood of the pregnant woman. It is important to highlight that families buying this test, and getting a normal result, may be provided with a false sense of security. Thus, careful and comprehensive genetic counselling should be performed before the test is offered, and should include a clear explanation of the advantages and disadvantages, as well as limitations, compared to other methods.

Genetics and Molecular Diagnostics in Retinoblastoma--An Update

Retinoblastoma is the prototype genetic cancer: in one or both eyes of young children, most retinoblastomas are initiated by biallelic mutation of the retinoblastoma tumor suppressor gene, RB1, in a developing retinal cell. All those with bilateral retinoblastoma have heritable cancer, although 95% have not inherited the RB1 mutation. Non-heritable retinoblastoma is always unilateral, with 98% caused by loss of both RB1 alleles from the tumor, whereas 2% have normal RB1 in tumors initiated by amplification of the MYCN oncogene. Good understanding of retinoblastoma genetics supports optimal care for retinoblastoma children and their families. Retinoblastoma is the first cancer to officially acknowledge the seminal role of genetics in cancer, by incorporating "H" into the eighth edition of cancer staging (2017): those who carry the RB1 cancer-predisposing gene are H1; those proven to not carry the familial RB1 mutation are H0; and those at unknown risk are HX. We suggest H0* be used for those with residual <1% risk to carry a RB1 mutation due to undetectable mosaicism. Loss of RB1 from a susceptible developing retinal cell initiates the benign precursor, retinoma. Progressive genomic changes result in retinoblastoma, and cancer progression ensues with increasing genomic disarray. Looking forward, novel therapies are anticipated from studies of retinoblastoma and metastatic tumor cells and the second primary cancers that the carriers of RB1 mutations are at high risk to develop. Here, we summarize the concepts of retinoblastoma genetics for ophthalmologists in a question/answer format to assist in the care of patients and their families.

Targeted capture enrichment assay for non-invasive prenatal testing of large and small size sub-chromosomal deletions and duplications

Noninvasive prenatal testing (NIPT) using whole genome and targeted sequencing has become increasingly accepted for clinical detection of Trisomy 21 and sex chromosome aneuploidies. Few studies have shown that sub-chromosomal deletions or duplications associated with genetic syndromes can also be detected in the fetus noninvasively. There are still limitations on these methodologies such as the detection of variants of unknown clinical significance, high number of false positives, and difficulties to detect small aberrations. We utilized a recently developed targeted sequencing approach for the development of a NIPT assay, for large and small size deletions/duplications, which overcomes these existing limitations. Artificial pregnancies with microdeletion/microduplication syndromes were created by spiking DNA from affected samples into cell free DNA (cfDNA) from non-pregnant samples. Unaffected spiked samples and normal pregnancies were used as controls. Target Capture Sequences (TACS) for seven syndromes were designed and utilized for targeted capture enrichment followed by sequencing. Data was analyzed using a statistical pipeline to identify deletions or duplications on targeted regions. Following the assay development a proof of concept study using 33 normal pregnancies, 21 artificial affected and 17 artificial unaffected pregnancies was carried out to test the sensitivity and specificity of the assay. All 21 abnormal spiked-in samples were correctly classified as subchromosomal aneuploidies while the 33 normal pregnancies or 17 normal spiked-in samples resulted in a false positive result. We have developed an NIPT assay for the detection of sub-chromosomal deletions and duplications using the targeted capture enrichment technology. This assay demonstrates high accuracy, high read depth of the genomic region of interest, and can identify deletions/duplications as small as 0.5 Mb. NIPT of fetal microdeletion/microduplication syndromes can be of enormous benefit in the management of pregnancies at risk both for prospective parents and health care providers.

Comparison of adverse perinatal outcomes after single-needle and double-needle CVS techniques

OBJECTIVE

To determine the impact of the chorion villus sampling (CVS) technique on adverse perinatal outcomes.

METHODS

In this case-control study, 412 women who underwent CVS at 11-14 weeks of gestation and 231 women who did not undergo any invasive procedure were retrospectively evaluated. The women in the CVS group were further divided into two groups according to the use of single-needle technique (n=148) vs. double-needle technique (n=264). The adverse outcomes were compared between controls and the two CVS groups, and regression analysis was used to determine the significance of independent contribution.

RESULTS

The rate of preeclampsia for the control group was 2.2%, for the double-needle group was 3% and for the single-needle group was 8.1%. CVS with single-needle technique was found to be an independent and statistically significant risk factor for preeclampsia [odds ratio (OR)=2.1, 95% confidence interval (CI); 1.4-2.7, P=0.008].

CONCLUSION

The risk of preeclampsia after CVS appears to be increased with single-needle technique compared with double-needle technique.

Fetal loss following invasive prenatal testing: a comparison of transabdominal chorionic villus sampling, transcervical chorionic villus sampling and amniocentesis

OBJECTIVE

The aim of this study was to compare transabdominal chorionic villus sampling, transcervical chorionic villus sampling and amniocentesis with respect to their total fetal loss rates.

METHODS

We retrospectively evaluated procedures of invasive prenatal testing performed during a 14-year period (2001-2014) including 936 amniocentesis procedures and 1051 chorionic villus samplings, of which 405 cases were executed transabdominally and 646 transcervically. Only singleton pregnancies before 24 weeks and 0 days of gestation where the pregnancy outcome was known were included. Fetal loss was defined as an abortion occurring either before 24 weeks and 0 days of gestation or <2 weeks after the procedure.

RESULTS

The total fetal loss rates were determined to be 1.73% for transabdominal chorionic villus sampling, 2.01% for transcervical chorionic villus sampling and 1.18% for amniocentesis. No statistically noticeable differences between the total fetal loss rates of all three procedures were found (P=0.399).

CONCLUSION

Our study has shown that chorionic villus sampling (either transabdominal or transcervical) and amniocentesis are equal methods for invasive prenatal testing with respect to their abortion risk.

Ethical issues in genetic counseling

Genetics has made great progress in the past decades, and prenatal diagnosis, predictive genetic testing, and genetic counseling have drawn the limelight of public attention. Because the subject of genetic counseling is of crucial consequence for both the short and long term, its ethical aspects are paramount. The question is whether mankind is mature enough to use this extraordinary knowledge in the right way for the benefit of the society. In the center of ethical questions is the comprehensiveness of information provided to the couples or patients and counseling them about results and making informed educated decisions. In addition, it is crucial how sensitive personal information is treated and whether and how it should be made public.

First trimester contingent screening for trisomies 21,18,13: is this model cost efficient and feasible in public health system?

PURPOSE

To evaluate the effectiveness of three different first trimester screening models for trisomies 21, 18 and 13, in terms of detection rate, invasive test rate and final costs.

MATERIAL AND METHODS

We analyzed the distribution of risk for trisomies 21, 18 and 13 in a population of 20,831 singleton pregnancies based on maternal age, fetal heart rate, nuchal translucency, free beta human chorionic gonadotropin and pregnancy-associated plasma protein A (Combined test). On the basis of our data, we estimated the performance and cost of screening for trisomies using three different models at specific cutoffs: Combined test; Cell free DNA test and Contingent screening test.

RESULTS

Using Combined test, DR for major trisomies was estimated to be 94.92%, invasive test rate was 6.3%. cfDNA would result in a DR of 97.92%, with an invasive test rate of 3.64%. Contingent screening approach would result in an overall DR of 97.82, with a rate for invasive procedure of 1.36% and a final cost lower than other screening policies (2,338,433 euro vs 5,796,060 of cfDNA and 2,385,473 of Combined test).

CONCLUSIONS

Contingent screening test could be a cost-efficient and feasible first trimester screening test for aneuploidies in public health system.

Steroid 21-hydroxylase deficiency in congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) refers to a group of inherited genetic disorders involving deficiencies in enzymes that convert cholesterol to cortisol within the adrenal cortex. There are five key enzymes involved in the production of cortisol. Of these key enzymes, deficiency of 21-hydroxylase is the most commonly defective enzyme leading to CAH representing more than 90% of cases. The low adrenal cortisol levels associated with CAH affects the hypothalamic-pituitary-adrenal negative feedback system leading to increased pituitary adrenocorticotropic hormone (ACTH) production, which overstimulates the adrenal cortex in an attempt to increase cortisol production resulting in a hyperplastic adrenal cortex. The deficiency of enzyme 21-hydroxylase results from mutations or deletions in the CYP21A2 gene found on chromosome 6p. The disorder is transmitted as an autosomal recessive pattern and specific mutations may be correlated to enzymatic compromise of varying degrees, leading to the clinical manifestation of 21-hydroxylase deficiency (21-OHD) CAH.

Revisiting the challenges of training Maternal Fetal Medicine fellows in chorionic villus sampling

BACKGROUND

More than a decade ago, researchers described a survey of Maternal Fetal Medicine fellows that showed that chorionic villus sampling training was limited for Maternal Fetal Medicine fellows in the United States. Prenatal screening and diagnosis have rapidly evolved since then and include the introduction of noninvasive aneuploidy screening that uses cell-free fetal DNA. Yet, chorionic villus sampling remains the only method available for first-trimester genetic diagnosis.

OBJECTIVE

This study evaluated the chorionic villus sampling training of Maternal Fetal Medicine fellows with respect to availability, competency standards, and education methods.

STUDY DESIGN

In November 2015, an electronic survey was sent to Maternal Fetal Medicine fellows and fellowship directors of accredited Maternal Fetal Medicine fellowship programs in the United States.

RESULTS

Fifty-eight percent of fellows (179/310) and 46% of program directors (35/76) responded. Ninety-five percent of Maternal Fetal Medicine fellows think that invasive diagnostic testing is essential to their training; 100% of fellows have amniocentesis training; and 65% have chorionic villus sampling training. The median number of chorionic villus sampling procedures that are expected during a fellowship in those who trained was 10. Eighty-eight percent of fellows and 89% of program directors state that chorionic villus sampling training could be better; 89% of fellows and 97% of directors would like access to simulated models. Barriers to training included lack of patients (71%) and lack of proficient attending supervisors (43%).

CONCLUSION

Since the last survey, >10 years ago, chorionic villus sampling training has declined further. A decrease in the number of procedures that are performed is the leading barrier to this training.