Trends in the utilization of invasive prenatal diagnosis in The Netherlands during 2000-2009

Spectrum of Chromosomal Abnormalities Detected by Conventional Cytogenetic Analysis Following Invasive Prenatal Testing of Fetuses with Abnormal Ultrasound Scans

Objectives

The frequent association between malformations and chromosomal abnormalities is now well-established. This study looks at the incidence and type of chromosomal abnormalities detected by conventional cytogenetic analysis in women undergoing invasive tests following detection of fetal anomalies on antenatal scans as well as incidence of other genetic abnormalities detected by DNA analysis of fetuses with congenital anomalies that had a normal karyotype.

Materials and Methods

A retrospective, observational study of pregnant women undergoing invasive testing following identification of fetal anomalies by ultrasonography was carried out in a tertiary care facility, Vellore, India, between 2011 and 2018.

Results

169 women underwent an invasive diagnostic procedure following detection of fetal anomalies. The most common indication for doing fetal karyotype was the presence of major fetal structural anomalies (142/169, 84%) with over a third (48/142, 34%) having multisystem involvement. Fetal hydrops was the next most common indication, detected in 18/169 (10%) fetuses. Aneuploidy was seen 19 of 25 fetuses (76%) with an abnormal karyotype with autosomal aneuploidy accounting for 13 (68%) and sex chromosome aneuploidy for seven (37%) of the fetuses. One fetus had double aneuploidy. In fetuses with normal karyotype, no additional information was obtained from further genetic testing.

Conclusions

The overall detection rate of chromosomal abnormalities in our study using conventional cytogenetic analysis was 14.8%, the majority (72%) being associated with structural malformations, 20% with non-immune hydrops and 4% with soft markers. Abnormal karyotypes were seen in 12.7% of fetuses with structural malformations.

In-house genetic counseling increases the detection of abnormal karyotypes-a 26-year experience in prenatal diagnosis in a single tertiary referral hospital in Poland

Purpose

To evaluate the trends in prenatal diagnosis over 26 years in a tertiary referral hospital.

Methods

A retrospective analysis of invasive prenatal procedures performed between 1991 and 2016. Maternal characteristics, indications for invasive diagnosis, and percentage of abnormal karyotypes were compared between periods according to guidelines implemented nationally and locally.

Results

A total of 14,302 invasive prenatal procedures were performed. The proportion of invasive procedures performed for advanced maternal age, abnormal karyotype in a previous pregnancy, and maternal anxiety decreased from 71.1%, 17.8%, 8.9% in 1991 to 23.9%, 1.3%, and 2.3% in 2016 (OR 0.6, 0.8, and 0.9 for each 5 years, respectively; p < 0.001), while the proportion of invasive procedures performed for abnormal ultrasound increased from 2.2% in 1991 to 51.6% in 2016 (OR 1.9 for each 5 years; p < 0.001). Abnormal karyotype was found in 9.7%. The proportion of abnormal karyotypes increased significantly from 0.0% in 1991 to 15.7% in 2016 (OR 1.35 for each 5-year period; p < 0.001). The odds of abnormal karyotype increased after the implementation of the Ordinance of the Minister of Health in 2003 (OR 1.6), the National Prenatal Screening Program in 2007 (OR 2.2), and the in-house genetic counseling with combined first trimester screening in 2015 (OR 3.1).

Conclusions

Significant changes in prenatal diagnosis led to a better selection of patients undergoing invasive prenatal procedures. The implementation of in-house genetic counseling was associated with an increased rate of the detection of abnormal karyotypes.

Pedagogical strategies in teaching invasive prenatal procedures: a scoping review protocol

INTRODUCTION

Invasive prenatal procedures (IPP) are core competencies in a Maternal-Fetal Medicine (MFM) fellowship training programme yet no standardised competency-based curriculum exists. This scoping review aims to provide a comprehensive understanding of the existing educational strategies for amniocentesis, chorionic villus sampling, fetal blood sampling and intrauterine blood transfusion. The objective is also to describe current gaps in the literature regarding evidence-based standards for training and assessment in IPP. Finally, we hope to encourage medical educators who are seeking to develop curricula based on competence by design to foster adaptive expertise through incorporating contextual variations in their teaching thus helping future MFM specialists to handle challenges and respond creatively to changing clinical circumstances and environmental variations.

METHODS AND ANALYSIS

Using the five-stage framework of Arksey and O'Malley's scoping review methodology as a guide, we will perform a systematic search in the Medline, Embase and Cochrane library databases to identify relevant studies on the educational strategies for IPP. We will include relevant English articles published after 1978. For a comprehensive search, we will explore websites and key journals, and hand-searched reference lists of key studies. Key studies are articles deemed relevant according to the specific inclusion and exclusion criteria. We will chart and sort data using a descriptive and thematic analysis approach.

ETHICS AND DISSEMINATION

This review will be the first to examine all forms of pedagogical strategies used in training invasive fetal procedures. As an analysis of pre-existing available data in the literature, this scoping review does not require ethical approval. We anticipate that results will identify research gaps as well as novel ideas for education strategies and assessment. Findings from this study will be disseminated through publication in a peer-reviewed journal, medical education and clinical conferences, and in knowledge translation settings, aiming to improve clinical practice and quality of care.

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).

Implementing non-invasive prenatal testing for aneuploidy in a national healthcare system: global challenges and national solutions

Background

Since the introduction of non-invasive prenatal testing (NIPT) in 2011, mainly by commercial companies, a growing demand for NIPT from the public and healthcare professionals has been putting pressure on the healthcare systems of various countries. This study identifies the challenges of establishing a responsible implementation of NIPT for aneuploidy in prenatal healthcare, by looking at the Netherlands.

Methods

A mixed methods approach involving 13 stakeholder interviews, document analysis and (participatory) observations of the Dutch NIPT Consortium meetings were used. The Diffusion of Innovation Theory and a Network of Actors model were used to interpret the findings.

Results

Implementation of NIPT was facilitated by several factors. The set-up of a national NIPT Consortium enabled discussion and collaboration between stakeholders. Moreover, it led to the plan to offer NIPT through a nationwide research setting (TRIDENT studies), which created a learning phase for careful implementation. The Dutch legal context was perceived as a delaying factor, but eventually gave room for the parties involved to organise themselves and their practices.

Conclusions

This study shows that implementing advanced technologies with profound effects on prenatal care benefit from a learning phase that allows time to carefully evaluate the technical performance and women’s experiences and to enable public debate. Such a coordinated learning phase, involving all stakeholders, will stimulate the process of responsible and sustainable implementation.

First trimester screening cut-offs for noninvasive prenatal testing as a contingent screen: Balancing detection and screen-positive rates for trisomy 21

OBJECTIVE

To provide data on how screen-positive and detection rates of first trimester prenatal screening for fetal Down syndrome vary with changes in the risk cut-off and maternal age to inform contingency criteria for publicly funded noninvasive prenatal testing.

MATERIALS AND METHODS

First trimester screening and diagnostic data were collected for all women attending for first trimester fetal aneuploidy screening in Western Australia between 2005 and 2009. Prenatal screening and diagnostic data were linked to pregnancy outcomes, including data from the Midwives' Notification System and the Western Australian Registry of Developmental Anomalies. The prevalence of Down syndrome and performance of screening by risk cut-off and/or for women >35 years were analysed.

RESULTS

The current screening risk cut-off of 1:300 has screen-positive and detection rates of 3.5% and 82%. The screen-positive rate increases by 0.7-0.8% for each 100 point change in risk, up to 19.2% at 1:2500 (96% detection rate). Including all women >35 years as screen positive would increase the screen-positive rate and detection rates to 30.2% and 97.2%.

CONCLUSION

Variation in screening risk cut-off and the use of maternal age to assess eligibility for noninvasive testing could significantly impact the demand for, and cost of, the test. A contingent first trimester screening approach for risk assessment is superior to the use of a combination of screening and maternal age alone. These data will inform decisions regarding the criteria used to determine eligibility for publicly funded noninvasive prenatal testing.

Changing to NIPT as a first-tier screening test and future perspectives: opinions of health professionals

OBJECTIVE

The aim of this study was to investigate health professionals' opinions toward offering noninvasive prenatal testing (NIPT) as first-tier screening test regardless of pregnant women's risk, and toward a potential broader range of disorders.

METHODS

A questionnaire completed by obstetric health professionals (n = 240) after an in-service NIPT training in the West and North of the Netherlands.

RESULTS

The majority (72%) of respondents favored replacing first-trimester combined test (FCT) by NIPT, although 43% preferred to maintain nuchal translucency measurement. Many respondents believed that replacing FCT by NIPT would only have advantages (57%), would lead to more pregnant women opting for prenatal testing (69%), and would simplify counseling (47%). Differences in attitudes toward counseling between health professionals were observed. When considering NIPT to screen for broader range of disorders, the majority (92%) thought that this should include disorders characterized by neonatal death, whereas 52% of the respondents favored testing for fetomaternal risk factors. Overall, 46% thought screening should be offered as a fixed list of disorders.

CONCLUSION

Most health professionals favor NIPT instead of FCT but prefer to maintain nuchal translucency measurement. If NIPT becomes available as a first-tier screening test, attention remains necessary to ensure that pregnant women make well-informed decisions in line with the aim of prenatal screening.

Evaluation of the introduction of the national Down syndrome screening program in the Netherlands: age-related uptake of prenatal screening and invasive diagnostic testing

OBJECTIVE

To study the effect of different government prenatal screening (PNS) policies on the uptake of PNS and prenatal diagnostic testing (PND) over the periods 2001-2003 (PNS on request), 2004-2006 (permission to offer the first-trimester combined test (FCT) to women of advanced maternal age (AMA), with women aged <36 years informed on explicit request) and 2007-2010 (introduction of population screening) and to evaluate whether trends in uptake are related to maternal age. The indication AMA for PND is still warranted, and the costs for FCT are only reimbursed for AMA women.

STUDY DESIGN

Analysis of data on the first- and second-trimester screening program (n=41,600) for Down syndrome (DS) and on PND (n=10,795) performed from 2001 to 2010 in the region North-Holland of the Netherlands. To evaluate the actual participation in PNS and PND in different maternal age groups, estimation of the age distribution of women who underwent a fetal anomaly scan in 2009 (n=14,481) was used as a reference population (participation of 85.2%).

RESULTS

The overall uptake of FCT was 35.2% in 2010. Over the years the number of FCT in all age groups increased significantly (P<0.001). Overall the number of PND decreased significantly; the number of PND for AMA decreased and the number of PND for increased risk at FCT (in women <36 and ≥36 years) increased (P<0.05). Since 2004 significantly more DS cases were detected with FCT in AMA women and fewer with PND for AMA, and since 2007 more DS cases were detected with FCT in women <36 years (P<0.001).

CONCLUSION

The effect of the national screening program is limited. Significantly more women opt for PNS but the overall uptake remains low, especially in younger women. A significant number of AMA women still opt for PND for AMA. The choice for FCT and PND for AMA seems dependent on background risk. To accomplish a more effective screening policy, reimbursement of the cost of the test should apply to all women and the indication for PND for AMA should be abolished.

Best ethical practices for clinicians and laboratories in the provision of noninvasive prenatal testing

OBJECTIVE

The goal of this study is to provide an ethical framework for clinicians and companies providing noninvasive prenatal testing using cell-free fetal DNA or whole fetal cells.

METHOD

In collaboration with a National Institutes of Health-supported research ethics consultation committee together with feedback from an interdisciplinary group of clinicians, members of industry, legal experts, and genetic counselors, we developed a set of best practices for the provision of noninvasive prenatal genetic testing.

RESULTS

Principal recommendations include the amendment of current informed consent procedures to include attention to the noninvasive nature of new testing and the potential for a broader range of results earlier in the pregnancy. We strongly recommend that tests should only be provided through licensed medical providers and not directly to consumers.

CONCLUSION

Prenatal tests, including new methods using cell-free fetal DNA, are not currently regulated by government agencies, and limited professional guidance is available. In the absence of regulation, companies and clinicians should cooperate to adopt responsible best ethical practices in the provision of these tests.

Factors determining uptake of invasive testing following first-trimester combined testing

OBJECTIVE

This study aims to analyze differences in characteristics between women who opted for invasive testing after first-trimester combined testing and those who did not.

METHOD

Follow-up was performed in 20 215 combined tests conducted between 2007 and 2011 in the central region of the Netherlands. Multivariate logistic regression analysis compared variables (Down syndrome risk estimate, maternal age, previous Down syndrome pregnancy, IVF/ICSI, parity and nuchal translucency measurement) between different groups.

RESULTS

65.4% of women with a Down syndrome risk estimate ≥1 in 200 opted for invasive 49 testing. In a multivariate model, women opting for invasive testing were significantly younger (odds ratio 0.92; 95% confidence interval 0.88-0.95) and less likely to have had IVF/ICSI (odds ratio 0.57; 95% confidence interval 0.37-0.87) than women opting out on invasive testing. In this high risk group, women <36 years opted for invasive testing more frequently, regardless of their Down syndrome risk estimate magnitude. Women ≥36 years let the magnitude of the risk estimate count significantly in their decision to opt for invasive testing.

CONCLUSION

Because of the dissimilarity in the offer of prenatal screening and invasive diagnosis in the Dutch prenatal screening policy, women <36 years and women >36 years make different choices when confronted with similar Down syndrome risk estimates.

Prenatal Diagnosis of Chromosome Abnormalities: A 13-Year Institution Experience

Objective: To analyze trends in screening and invasive prenatal diagnosis of chromosome abnormalities (CA) over a 13-year period and correlate them to changes in the national prenatal screening policy. Methods: We retrospectively reviewed Down syndrome (DS) screening tests and fetal karyotypes obtained by prenatal invasive testing (IT) in our fetal medicine unit between January 1999 and December 2011. Results: A total of 24,226 prenatal screening tests for DS and 11,045 invasive procedures have been analyzed. Over a 13-year period, utilization of non-invasive screening methods has significantly increased from 57% to 89%. The percentage of invasive procedures has declined from 49% to 12%, although the percentage of IT performed for maternal anxiety has increased from 22% to 55%. The percentage of detected CA increased from 2.5% to 5.9%. Overall, 31 invasive procedures are needed to diagnose 1 abnormal case, being 23 procedures in medical indications and 241 procedures in non-medical indications. Conclusions: Our experience on screening and invasive prenatal diagnostic practice shows a decrease of the number of IT, with a parallel decline in medical indications. There is an increasing efficiency of prenatal screening program to detect CA. Despite the increasing screening policies, our population shows a growing request for prenatal IT. The a priori low risk population shows a not negligible residual risk for relevant CA. This observation challenges the current prenatal screening strategy focused on DS; showing that the residual risk is higher than the current cut-off used to indicate an invasive technique.

Array comparative genomic hybridization in prenatal diagnosis of first trimester pregnancies at high risk for chromosomal anomalies

Objective

To describe the diagnostic performance of array comparative genomic hybridization (aCGH) as a potential first line diagnostic method in first trimester high risk pregnancies.

Method

In a retrospective study we performed aCGH using a targeted array BAC platform (Constitutional Chip® 4.0, PerkinElmer, Turku Finland, median resolution 600 kB) and the Affymetrix Cytogenetics® Whole Genome 2.7 M array (at a resolution of 400kB) on 100 anonymized prenatal samples from first trimester high risk pregnancies with normal conventional karyotype. We studied the technical feasibility and turn-around-time as well as the detection rate of pathogenic submicroscopic chromosome anomalies and CNVs of unknown significance.

Results

We obtained results in 98 of 100 samples in 3 to a maximum of 5 days after DNA extraction. At the given resolution we did not identify any additional pathogenic CNVs but two CNVs of unknown significance in the chromosomal regions 1q21.1q21.2 (deletion) and 5p15.33 (duplication) (2%).

Conclusion

In accordance with a growing number of reports this study supports the concept that aCGH at a resolution of 400-600kB may be used as a first line prenatal diagnostic test with high diagnostic safety and rapid turn-around time in high-risk first trimester pregnancies. Detection rate of CNVs of unknown significance, considered as a major hindrance for replacing conventional karyotyping by aCGH, is 2%, but the diagnosis of additional submicroscopic anomalies in this heterogeneous group of patients seems to be rare.

Pathologic ultrasound findings and risk for congenital anomalies in teenage pregnancies

OBJECTIVE

To detect the number and diagnosis of fetal malformations in teenage pregnancies and to evaluate whether low maternal age or epigenetic factors have an influence on this issue.

MATERIALS AND METHODS

We performed a retrospective analysis in a single center for prenatal diagnostics in Northern Germany. We searched our electronic databank for all pregnancies with maternal age under 20 years. Pregnancy outcome and fetal malformations are described.

RESULTS

The incidence of teenage pregnancies in our study was 638 patients (4.4%). The total of fetal malformations in teenage pregnancies was 51(8.3%). Chromosomal aberrations were found in 5 cases (0.9%). 9 cases of fetal gastroschisis as one of the most frequent malformations were followed up and neonatal outcome was uneventful. Furthermore we found 16 cases with different heart defects and 30 cases with other malformations. Patients' body mass indices showed an increase over the years and nicotine consumption was testified in more than 50% of the patients.

CONCLUSIONS

Teenage pregnancies are at risk for fetal non-chromosomal and chromosomal abnormalities. As these might be detected by first-trimester-screening prenatal care in teenage pregnancies should include at least early ultrasound examination. Epigenetic factors may play a key role in certain fetal malformations.