Prenatal screening for fetal aneuploidy in singleton pregnancies

Expansion of non-invasive prenatal screening to the screening of 10 types of chromosomal anomalies: a cost-effectiveness analysis

OBJECTIVES

To determine the cost-effectiveness of the addition of chromosomal anomalies detectable by non-invasive prenatal screening (NIPS), in a prenatal screening programme targeting common aneuploidies.

DESIGN, SETTING AND PARTICIPANTS

A simulation study was conducted to study the addition of chromosomal anomalies detectable by NIPS (sex chromosome aneuploidies, 22q11.2 deletion syndrome, large deletion/duplication >7 Mb and rare autosomal trisomies) to five basic strategies currently aiming the common trisomies: three strategies currently offered by the public healthcare systems in Canada, whose first-tier test is performed with biochemical markers, and two programmes whose first-tier test consists of NIPS-based methods.

OUTCOME MEASURES

The total number of cases of chromosomal anomalies detected and the costs related to the consumption of medical services.

RESULTS

The most effective and the most cost-effective option in almost all prenatal screening strategies is the option that includes all targeted additional conditions. In the strategies where NIPS is used as first-tier testing, the cost per additional case detected by adding all possible additional anomalies to a programme that currently targets only common trisomies is $C25 710 (95% CI $C25 489 to $C25 934) for massively parallel shotgun sequencing and $C57 711 (95% CI $C57 141 to $C58 292) for targeted massively parallel sequencing, respectively. The acceptability curves show that at a willingness-to-pay of $C50 000 per one additional case detected, the expansion of NIPS-based methods for the detection of all possible additional conditions has a 90% probability of being cost-effective.

CONCLUSION

From an economic perspective, in strategies that use NIPS as a first-tier screening test, expanding the programmes to detect any considered chromosomal anomalies other than the three common trisomies would be cost-effective. However, the potential expansion of prenatal screening programmes also requires consideration of societal issues, including ethical ones.

The Effect of Resolution Level and Targeted Design in the Diagnostic Performance of Prenatal Chromosomal Microarray Analysis

INTRODUCTION

This study was performed to assess the optimal resolution for prenatal testing by array comparative genomic hybridization (aCGH), aiming to balance between maximum diagnostic yield and minimal detection of variants of uncertain significance (VOUS).

METHODS

This was a prospective study using data of 2,336 fetuses that underwent invasive prenatal diagnosis, and the samples were analyzed by aCGH. In total, six different aCGH platforms were studied; four different resolutions (0.18 Mb, 0.5 Mb, 1 Mb, and 2 Mb) and two platform designs (whole-genome [WG] and targeted). The results of these designs were compared based on their diagnostic yield and VOUS rate. The performance of the different designs was further analyzed according to indication for invasive testing.

RESULTS

The diagnostic yield of copy number variants increased with increasing level of analysis. The detection rates of clinically significant chromosomal abnormalities were almost the same across our targeted array designs; 7.2% with 0.18 Mb backbone/0.05 Mb versus 7.1% with 0.5 Mb backbone/0.05 Mb (p >0.05). However, a significant difference in the rate of VOUS was observed; 9.4% with 0.18 Mb backbone/0.05 Mb versus 6% with 0.5 Mb backbone/0.05 Mb (p <0.001). After analyzing the results across different indications for testing, we found that the application of non-targeted platform designs and lower levels of resolution analysis (such as 1 Mb WG or 0.5 MbL/1 MbG WG) would offer similar diagnostic yield in most cases with major congenital anomalies, with lower VOUS rates. However, the sample size for many indication groups was too small to extract robust associations.

CONCLUSION

It appears that the targeted array platform with 0.5 Mb backbone resolution and 0.05 Mb on targeted gene-rich regions is optimal for routine chromosomal microarray analysis use in prenatal diagnosis. It may be beneficial to individualize the minimum resolution in specific referral indications as the indications for invasive prenatal testing may be quite heterogeneous.

Genetic Implications in High-Risk Pregnancy and Its Outcome: A 2-Year Study

OBJECTIVE

The aim of this study is to evaluate high-risk pregnant females' offspring as regard the presence of any medical condition, hereditary disorder, or major anomaly as well as to document parental sociodemographic characteristics and compliance with follow-up schedules of fetal medicine and clinical genetic clinics.

STUDY DESIGN

This prospective 2-year cohort study of neonates and infants reported the referral indications, investigations, and diagnoses obtained through prenatal and postnatal examinations. It also reported their parental follow-up vigilance.

RESULTS

Of the 811 infants of high risk females referred 460 (56.7%) came for assessment. Mean parental consanguinity and endogamy were 67 and 71.3%, respectively. All pregnant mothers underwent first-trimester biochemical testing (plasma protein-A, α-fetoprotein [AFP], human chorionic gonadotropin [hCG]) and serial ultrasound examinations. Seventy mothers needed second-trimester biochemical testing (AFP, hCG, and estriol). Sixty-two mothers underwent amniocentesis where G-banding karyotype, fluorescence in situ hybridization and targeted molecular testing for the specific gene mutation of single gene disorders were conducted according to suspected disorders. High quality fetal ultrasound was performed when brain malformations were suspected, while 16 fetuses required brain MRI examination. Mean age of newborns at first examination was 26.5 days. They were grouped according to the maternal indication for referral. Upon examination, 18 neonates had confirmed congenital malformations/genetic disorders. Five of them were diagnosed prenatally. In four other fetuses with single gene disorder, the molecular diagnosis of their affected siblings was not established prior to this pregnancy; thus, prenatal diagnosis was not possible. The remaining nine cases were diagnosed postnatally.

CONCLUSION

Parental consanguinity and endogamy were increased among high-risk pregnancies. Public awareness about potential adverse effects of consanguineous marriages and the importance of genetic testing are imperative. A structured multidisciplinary team of specialists in fetal medicine, clinical genetics, and neonatology provides good genetic services. Expansion and financial support of these services are urgently required.

KEY POINTS

· A multidisciplinary team provides good genetic services in high-risk pregnancies.. · Parental consanguinity and endogamy are increased among high-risk pregnancies.. · Increased public awareness about genetic testing importance and financial support are imperative..

Invasive Prenatal Diagnostic Testing for Aneuploidies in Singleton Pregnancies: A Comparative Review of Major Guidelines

Sophisticated screening protocols for genetic abnormalities constitute an important component of current prenatal care, aiming to identify high-risk pregnancies and offer appropriate counseling to parents regarding their options. Definite prenatal diagnosis is only possible by invasive prenatal diagnostic testing (IPDT), mainly including amniocentesis and chorionic villous sampling (CVS). The aim of this comparative review was to summarize and compare the existing recommendations on IPDT from the most influential guidelines. All the reviewed guidelines highlight that IPDT is indicated based on a positive screening test rather than maternal age alone. Other indications arise from medical history and sonography, with significant variations identified between the guidelines. The earlier time for amniocentesis is unequivocally set at ≥15 gestational weeks, whereas for CVS, the earlier limit varies from ≥10 to ≥11 weeks. Certain technical aspects and the overall approach demonstrate significant differences. Periprocedural management regarding Rhesus alloimmunization, virologic status and use of anesthesia or antibiotics are either inconsistent or insufficiently addressed. The synthesis of an evidence-based algorithm for IPDT is of crucial importance to healthcare professionals implicated in prenatal care to avoid unnecessary interventions without compromising optimal prenatal care.

Ethical Aspects of Prenatal DNA Testing

Cell-free DNA (cfDNA) first-trimester screening for fetal aneuploidies, as a non-invasive, safe, and rather accurate method, has changed prenatal screening policies all over the world. Owing to aggressive marketing, cfDNA screening tests exhibit global popularity and a rapid spread in routine prenatal care. However, wide availability of the tests, together with observed difficulties in the test’s interpretation, bring to light several serious ethical concerns. To date it is vital to identify and address the most important ethical, legal, and social issues regarding prenatal screening tests. Furthermore, guidelines and restrictions in certain cfDNA screening advancements that may provide information regarding fetal genetic traits of unknown clinical significance, conditions with variable penetrance, or late-onset conditions, should be considered.

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.

Sex Differences Are Here to Stay: Relevance to Prenatal Care

Sex differences exist in the incidence and presentation of many pregnancy complications, including but not limited to pregnancy loss, spontaneous preterm birth, and fetal growth restriction. Sex differences arise very early in development due to differential gene expression from the X and Y chromosomes, and later may also be influenced by the action of gonadal steroid hormones. Though offspring sex is not considered in most prenatal diagnostic or therapeutic strategies currently in use, it may be beneficial to consider sex differences and the associated mechanisms underlying pregnancy complications. This review will cover (i) the prevalence and presentation of sex differences that occur in perinatal complications, particularly with a focus on the placenta; (ii) possible mechanisms underlying the development of sex differences in placental function and pregnancy phenotypes; and (iii) knowledge gaps that should be addressed in the development of diagnostic or risk prediction tools for such complications, with an emphasis on those for which it would be important to consider sex.

Introducing cell-free DNA noninvasive testing in a Down syndrome public health screening program: a budget impact analysis

BACKGROUND

Non-invasive prenatal testing (NIPT) using cell-free fetal DNA in maternal plasma is a high accurate test for prenatal screening for Down syndrome. Although it has been reported to be cost effective as a contingent test, evidence about its budget impact is lacking.

OBJECTIVE

To evaluate, using computer simulations, the budget impact of implementing NIPT as a contingent test in the Quebec Program of screening for Trisomy 21.

METHODS

A semi-Markov analytic model built to simulate the budget impact of implementing NIPT into the current Quebec Trisomy 21 public Prenatal Screening, Serum Integrated prenatal screening (SIPS). Comparisons were made for a virtual population similar to that of expected Quebec pregnant women in 2015 in terms of size and age. Data input parameters were retrieved from a thorough literature search and in government databases, especially data from Quebec Program of screening for Trisomy 21. The 2015-2016 fiscal year budget impact was estimated from the Quebec healthcare system perspective and was expressed as the difference in the overall costs between the two alternatives (SIPS minus SPS + NIPT).

RESULTS

Our study found that, at a baseline cost for NIPT of CAD$ 795, NIPT as a second-tier test offered to high-risk women identified by current screening program (SIPS + NIPT) may be affordable for Quebec health care system. Compared to the current screening program, it would be implemented at a neutral cost, considering a modest annual savings of $ 80,432 (95% CI $ 79, $ 874-$ 81,462). Results were sensitive to the NIPT costs and the uptake-rate of invasive diagnostic tests.

CONCLUSION

Introducing NIPT as a contingent test in the Quebec Trisomy 21 screening program is an affordable strategy compared to the current practice. Further research is needed to confirm if our results can be reproduced in other healthcare jurisdictions.

Committee Opinion No. 406: Prenatal Testing After IVF With Preimplantation Genetic Testing for Aneuploidy

OBJECTIVE

To review the approach to prenatal genetic screening and diagnosis for chromosomal abnormalities in pregnancies conceived through in vitro fertilization and following preimplantation genetic testing for aneuploidy.

INTENDED USERS

General practitioners, family physicians, obstetricians, midwives, nurses, maternal-fetal medicine specialists, fertility specialists, genetic counsellors, geneticists, and other health care providers involved in prenatal screening.

TARGET POPULATION

All individuals or couples who conceivd through in vitro fertilization and underwent preimplantation genetic testing for aneuploidy.

EVIDENCE

Literature published in or before September 2018 was retrieved through searches of Medline, PubMed, and the Cochrane Library. SUMMARY STATEMENTS.

Use of Placental Growth Factor for Trisomy 21 Screening in Pregnancy: A Systematic Review

Background  Prenatal serum screening is an important modality to screen for aneuploidy in pregnancy. The addition of placental growth factor (PLGF) to screen for trisomy 21 remains controversial. Objective  To determine whether the addition of PLGF to combined serum aneuploidy screening improves detection rates (DRs) for trisomy 21. Study Design  We performed a systematic review of the literature until October 2019 to determine the benefits of adding PLGF to prenatal screening. We performed a goodness-of-fit test and retrieved the coefficient of determinations ( R ² ) as a function of false positive rates (FPRs), providing mean-weighted improvements in the DRs after accounting for PLGF levels. Results  We identified 51 studies, of which 8 met inclusion criteria (834 aneuploidy cases and 105,904 euploid controls). DRs were proportional to FPR across all studies, ranging from 59.0 to 95.3% without PLGF and 61.0 to 96.3% with PLGF (FPR 1-5%). Goodness-of-fit regression analysis revealed a logarithmic distribution of DRs as a function of the FPR, with R ²  = 0.109 (no PLGF) and R ²  = 0.06 (PLGF). Two-sample Kolmogorov-Smirnov's test reveals a p -value of 0.44. Overall, addition of PLGF improves DRs of 3.3% for 1% FPR, 1.7% for 3% FPR, and 1.4% for 5% FPR, respectively. Conclusion  Addition of PLGF to prenatal screening using serum analytes mildly improves trisomy 21 DRs as a function of FPRs.

Physicians' perception toward non-invasive prenatal testing through the eye of the Rogers' diffusion of innovation theory in China

OBJECTIVE

Physicians' attitudes and adoption behavior toward the delivery of prenatal tests take vital significance for its influence on their professional practice and patient acceptance. This study aimed to identify how physicians have perceived the diffusion of non-invasive prenatal testing (NIPT) in China.

METHODS

A cross-sectional study was conducted from July 2016 to October 2016 in Shanghai, and Fujian and Sichuan Provinces in China. Physicians working on prenatal screening completed a self-report questionnaire. Following Roger's diffusion of innovation model, multivariable logistic regressions were performed separately for the following key elements of the theory which influence diffusion: physician-perceived attributes of NIPT, communication channels, the nature of the social system, the extent of change agent (who introduces innovations into a society), promotion efforts, and physicians' benefits from adopting NIPT.

RESULTS

Most specialists had a positive attitude (53.2 percent) toward NIPT, whereas 58.9 percent of physicians had already adopted NIPT in their clinical practice. Physician adoption of NIPT was positively associated with the strength of HTA evidence (p = .03), perceived communication frequency with colleagues (p = .04), adoption by other physicians (p = .07), hospital competition (p = .06), hospital teaching status (p = .02), perceived for-profit genetic testing company's promotion (p < .001), and perceived clinical practice skill improvement (p = .02). However, the adoption behavior toward NIPT may be negatively associated with physician-perceived ethical concerns of NIPT (p = .06).

CONCLUSION

Obstetricians and gynecologists' positive perceptions facilitate the adoption of NIPT. Combined with cost-effectiveness analysis of prenatal screening methods, health policy makers can promote the adoption of appropriate, cost-effective prenatal screening in pregnant women.

Amniotic fluid concentrations of soluble endoglin and endothelial cell-specific molecule-1 in pregnancies complicated with neural tube defects

Objective To determine the concentrations of soluble endoglin (sCD105) and endothelial cell-specific molecule-1 (ESM-1) in the amniotic fluid (AF) of pregnant women, and to investigate the relationship between these concentrations and neural tube defects (NTDs). Methods AF concentrations of sCD105 and ESM-1 were measured in the study group, which included 60 pregnant women complicated with NTDs, and 64 pregnant women with unaffected healthy fetuses (control group). The AF concentrations of sCD105 and ESM-1 in both groups were measured using enzyme-linked immunosorbent assay and compared. Results There were no significant differences in terms of the mean AF concentrations of sCD105 and ESM-1 between the groups (P=0.141, P=0.084, respectively). There was a significant difference between the AF sCD105 concentrations in those with gestational age <24 weeks (n=101) and ≥24 weeks (n=23) (X̅<24=76.35±126.62 vs. X≥24=39.87±58.32, P=0.041). AF ESM-1 concentrations were found to be statistically significant in the gestational age <22 weeks (n=90) and ≥22 weeks (n=34) groups (X̅<22=135.91±19.26 vs. X̅≥22=148.56±46.85, P=0.035). A positive and low-level relation at a statistically significant level was determined between the gestational age and AF ESM-1 concentration in the study group (r=0.257; P=0.048). Conclusion AF concentrations of sCD105 and ESM-1 were not associated with the development of NTDs. Unlike studies that reported that ESM-1 concentrations decreased in maternal plasma with increased gestational age, we determined an increase that was proportionate to gestational age in AF.

Cytogenetic analysis of 3387 umbilical cord blood in pregnant women at high risk for chromosomal abnormalities

Background

Cordocentesis in our practice is most commonly indicated for rapid karyotyping in the second or third trimester and is regarded as the gold standard for foetal chromosomal aberration diagnosis in pregnancies at high risk for chromosomal abnormalities. In this study, we investigated 3387 umbilical cord blood samples for karyotyping from pregnant women who underwent cordocentesis and explored the pregnancy outcomes of foetal sex chromosome mosaicism and chromosomal polymorphism.

Results

Out of the 3387 samples, 182 abnormal karyotypes were detected. Ultrasound soft markers were the most common prenatal diagnostic indication, but the detection rate of abnormal karyotypes was 2.02%, while it was 46.97% in the genome-wide NIPT-positive group. The rate of aneuploidy was lower in the soft marker group than in the other groups. Out of 16 cases with sex chromosome mosaicism, three pregnant women with foetuses with a lower proportion of sex chromosome mosaicism delivered healthy foetuses; the foetus with karyotype 46,X,i(Y)(q10)[20]/45,X[6] showed unclear genitals. Three foetuses with chromosomal polymorphisms had postnatal disorders.

Conclusions

NIPT should not be recommended as the first-tier screening for chromosomal aberration for pregnancies with ultrasound soft markers or pathological ultrasound findings, but NIPT can be considered an acceptable alternative for pregnancies with contraindications to cordocentesis or the fear of procedure-related foetal loss. Mosaicism found in amniotic fluid cell culture requires further cordocentesis for karyotype confirmation, and the continuation of pregnancy is safe when a normal karyotype is identified in foetal blood culture. Further genetic testing and parental karyotype analysis are needed for foetal chromosomal polymorphisms.

Cost-effectiveness of prenatal screening and diagnostic strategies for Down syndrome: A microsimulation modeling analysis

Objectives

Down syndrome (DS) is the most frequently occurring fetal chromosomal abnormality and different prenatal screening strategies are used for determining risk of DS worldwide. New non-invasive prenatal testing (NIPT), which uses cell-free fetal DNA in maternal blood can provide benefits due to its higher sensitivity and specificity in comparison to conventional screening tests. This study aimed to assess the cost-effectiveness of using population-level NIPT in fetal aneuploidy screening for DS.

Methods

We developed a microsimulation decision-analytic model to perform a probabilistic cost-effectiveness analysis (CEA) of prenatal screening and diagnostic strategies for DS. The model followed individual simulated pregnant women through the pregnancy pathway. The comparators were serum-only screening, contingent NIPT (i.e., NIPT as a second-tier screening test) and universal NIPT (i.e., NIPT as a first-tier screening test). To address uncertainty around the model parameters, the expected values of costs and quality-adjusted life-years (QALYs) in the base case and all scenario analyses were obtained through probabilistic analysis from a Monte Carlo simulation.

Results

Base case and scenario analyses were conducted by repeating the micro-simulation 1,000 times for a sample of 45,605 pregnant women per the population of British Columbia, Canada (N = 4.8 million). Preliminary results of the sequential CEAs showed that contingent NIPT was a dominant strategy compared to serum-only screening. Compared with contingent NIPT, universal NIPT at the current test price was not cost-effective with an incremental cost-effectiveness ratio over $100,000/QALY. Contingent NIPT also had the lowest cost per DS case detected among these three strategies.

Conclusion

Including NIPT in existing prenatal screening for DS is shown to be beneficial over conventional testing. However, at current prices, implementation of NIPT as a second-tier screening test is more cost-effective than deploying it as a universal test.

No. 363-Investigation and Management of Non-immune Fetal Hydrops

OBJECTIVE

To describe the current investigation and management of non-immune fetal hydrops with a focus on treatable or recurring etiologies.

OUTCOMES

To provide better counselling and management in cases of prenatally diagnosed non-immune hydrops.

EVIDENCE

Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in 2017 using key words (non-immune hydrops fetalis, fetal hydrops, fetal therapy, fetal metabolism). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, observational studies, and significant case reports. Additional publications were identified from the bibliographies of these articles. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2017. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinicalpractice guideline collections, clinical trial registries, and national and international medical specialty societies.

BENEFITS, HARMS, AND COSTS

These guidelines educate readers about the causes of non-immune fetal hydrops and its prenatal counselling and management. It also provides a standardized approach to non-immune fetal hydrops, emphasizing the search for prenatally treatable conditions and recurrent genetic etiologies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care.

RECOMMENDATIONS

First Trimester Screening for Fetal Aneuploidies Using Placental Growth Factor: The Great Obstetrical Syndrome (GOS) Study

OBJECTIVE

This study sought to estimate the ability of first trimester maternal serum placental growth factor (PlGF) to identify fetal aneuploidies.

METHODS

A prospective cohort study of singleton pregnancy at 11 to 13 weeks was conducted. Maternal serum PlGF concentration was measured using BRAHMS PlGF plus KRYPTOR automated assays (Thermo Scientific BRAHMS, Hennigsdorf, Germany). PlGF and nuchal translucency were log-transformed and reported as multiples of the median (MoM) adjusted for crown-rump length. Detection rates were calculated using receiver-operator characteristic curves.

RESULTS

The study observed 21 cases of fetal aneuploidies (0.4%) out of 4765 participants. Trisomy 21 (13 cases; 0.85 MoM; interquartile range [IQR] 0.80-0.93), trisomy 18 (two cases; 0.77 MoM; IQR 0.66-0.87) and trisomy 13 (two cases; 0.68 MoM; IQR 0.61-0.75) were associated with low PlGF concentrations. The low PlGF values observed in the cases of monosomy X (two cases; 0.85 MoM; IQR 0.82-0.88, P = 0.05), triploidy (0.78 MoM, P = 0.11), and 47,XX,i(22)(p10) (0.18 MoM, P = 0.08) were not statistically different from the controls. A model including maternal age, nuchal translucency, and PlGF could have identified all (95% CI 83%-100%) cases of trisomy 21 and six of the other fetal aneuploidies (75%) at a false-positive rate of 9%.

CONCLUSION

Low first trimester PlGF is associated with an increased risk of fetal aneuploidy. PlGF combined with first trimester ultrasound (nuchal translucency, uterine artery Doppler, and early fetal anatomy) could identify not only women at high risk for preeclampsia, but also fetuses at high risk of aneuploidy for optimal further testing (non-invasive testing for common aneuploidy screening or chorionic villus sampling for full screening and diagnosis).

Cross-cultural perspectives on decision making regarding noninvasive prenatal testing: A comparative study of Lebanon and Quebec

Noninvasive prenatal testing (NIPT), based on the detection of cell-free fetal DNA in maternal blood, has transformed the landscape of prenatal care by offering clinical benefits (noninvasive, high specificity and sensitivity, early detection of abnormalities) compared to existing prenatal screening tests. NIPT has expanded rapidly and is currently commercially available in most of the world. As NIPT spreads globally, culturally sensitive and ethically sound implementation will require policies that take into consideration the social and cultural context of prenatal testing decisions. In a Western context, the main ethical argument for providing access and public funding of prenatal tests is the promotion of reproductive autonomy (also referred to as "procreative liberty" and "reproductive freedom"), by enabling pregnant women and couples to access information about the fetus in order to choose a certain course of action for pregnancy management (continuation of pregnancy and preparation for birth or termination). So how is the framework of reproductive autonomy operationalized in non-Western cultural contexts? We used Quebec, Canada, and Beirut, Lebanon, for case studies to explore what ethical considerations related to reproductive autonomy should guide the implementation of the test in various cultural contexts. To answer this question, we conducted a qualitative study to (1) explore the perceptions, values, and preferences of pregnant women and their partners about NIPT and (2) examine how these values and perceptions influence reproductive autonomy and decision making in relation to NIPT in these two different cultural settings, Lebanon and Quebec. Our findings may guide health care professionals in providing counseling and in helping women and their partners make better informed prenatal testing decisions. Further, at a policy level, such understanding might inform the development of local guidelines and policies that are appropriate to each context.

No. 348-Joint SOGC-CCMG Guideline: Update on Prenatal Screening for Fetal Aneuploidy, Fetal Anomalies, and Adverse Pregnancy Outcomes

OBJECTIVE

To review the available prenatal screening options in light of the recent technical advances and to provide an update of previous guidelines in the field of prenatal screening.

INTENDED USERS

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

TARGET POPULATION

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

EVIDENCE

Published literature was retrieved through searches of Medline, PubMed, and the Cochrane Library in and prior to March 2016 using an appropriate controlled vocabulary (prenatal diagnosis, amniocentesis, chorionic villi sampling, non-invasive prenatal screening) and key words (prenatal screening, prenatal genetic counselling). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies written in English and published from January 1985 to May 2016. Searches were updated on a regular basis and incorporated in the guideline. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical speciality societies.

GUIDELINE UPDATE

Evidence will be reviewed 5 years after publication to determine whether all or part of the guideline should be updated. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations.

The natural history of pregnancies with prenatal diagnosis of Trisomy 18 or Trisomy 13: Retrospective cases of a 23-year experience in a Brazilian public hospital

Trisomy 18 (T18) and trisomy 13 (T13) are polymalformative syndromes associated with a high rate of spontaneous abortions, intrauterine death, and short postnatal life. This study describes the overall outcome in a country where the therapeutic interruption of pregnancy is not available. The medical records of women with prenatal diagnosis of full trisomy of T13 or T18 between October 1994 and October 2017 were analyzed in order to describe their natural outcomes. Thirteen cases of T13 and 29 cases of T18 were included. The miscarriage rate was 9% for T18 and no cases for T13. Intrauterine fetal death occurred in 46% and 52% of cases for T13 and T18, respectively. The rate of live births for T13 was 54%, and the median survival was one day (95% CI -33.55 - 90.40) and 71% died in the first 24 hours of life. The rate of live births for T18 was 37% and the median survival was two days (95% CI -1.89 - 13.17); 90% of the affected babies died within first week of life. For the affected babies reaching the first year of life and for those who lived longer, multiple invasive and expensive procedures were required, without success in prolonging life beyond 180 days. This large series provides information for professionals and women regarding the natural histories of T13 and T18. Results of this study are consistent with those referenced in the literature, emphasizing the need of structured protocols and guidelines aiming early T13 and T18 diagnosis, prenatal care, gestation/parents follow-up, and counseling processes. For those couples with earlier diagnosis, a better follow-up and counseling during the prenatal care lead to the option for a support or palliative management of the newborn. Finally, when the counseling process is appropriate, it becomes easier to take decisions respecting the parent’s autonomy and to look for better outcomes for both, the mother and the fetus.

Care plans for women pregnant using assisted reproductive technologies: a systematic review

Background

Between 1 and 5% of children in industrialized countries are conceived through Assisted Reproductive Technologies (ART). As infertility and the use of ART may be associated with adverse perinatal outcomes, care plans specific to these pregnancies are needed. We conducted a systematic review to examine the existing care plans specific to women pregnant following Assisted Reproductive Technologies (ART).

Methods

MEDLINE, Embase and the Cochrane Library were searched by a senior information specialist. The population of interest included women becoming pregnant with ART (e.g., Intra-Uterine Insemination, In Vitro Fertilization (IVF), Intracytoplasmic Sperm Injection (ICSI), and surrogacy). All proposed care plans were sought that pertained to any aspect of care during pregnancy and delivery. Only Clinical Practice Guidelines (CPGs) addressing the recommendations and plans for the care of ART pregnant women were included. The search was restricted to the publication dates 2007 to June 12, 2017 when the search was run. The search was not restricted by language, however only English and French language guidelines were considered for inclusion.

Results

After screening 2078 citations, a total of ten CPGs were included. The following key clinical messages were prevalent: (1) although there was no supporting evidence, antenatal care for ART pregnancies should be provided by specialist with knowledge in obstetrics; (2) high-order multiple pregnancies are the greatest risk of ART and selective reduction options should be discussed; (3) there is some evidence of increased risk of congenital abnormalities and prenatal genetic and anatomic screening is recommended, especially in IVF-ICSI pregnancies; (4) due to a lack of or conflicting evidence, treatment of venous thromboembolism, antithrombotic therapy, treatment for hypothyroidism, and women with positive thyroid antibodies is recommended to be the same as in spontaneous pregnancies; and lastly (5) since an increased level of distress is a recognized feature in these pregnancies, psychosocial care and counselling should be considered.

Conclusions

There is a lack of CPGs specific to ART pregnancies. While we identified a small number of recommendations for ART pregnancies, specific interventions and models of care aiming at decreasing adverse maternal and perinatal outcomes following ART should be developed, implemented, and evaluated.

Electronic supplementary material

The online version of this article (10.1186/s12978-019-0667-z) contains supplementary material, which is available to authorized users.

The value of non-invasive prenatal testing: preferences of Canadian pregnant women, their partners, and health professionals regarding NIPT use and access

Background

Canadian policies regarding the implementation and public coverage of non-invasive prenatal testing (NIPT) are heterogeneous and shifting, with NIPT being publicly covered for high-risk pregnancies in some provinces, but not others. Such a diverse and evolving policy landscape provides fertile ground for examining the preferences of pregnant women, their partners, and health professionals regarding the implementation and coverage of NIPT by the public healthcare system, as well as the factors influencing their preferences, which is what the present study does.

Methods

In this paper, we report the results of three-large scale Canadian surveys, in which 882 pregnant women, 395 partners of pregnant women, and 184 healthcare professionals participated.

Results

The paper focuses on preferences regarding how and when NIPT should be used, as well as the factors influencing these preferences, and how coverage for NIPT should be provided. These are correlated with respondents’ levels of knowledge about Down syndrome and testing technologies and with their stated intended use of NIPT results.

Conclusion

Salient is the marked difference between the preferences of prospective parents and those of healthcare professionals, which has potential implications for Canadian policy regarding NIPT implementation and insurance coverage.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-2153-y) contains supplementary material, which is available to authorized users.

Reference values of nuchal fold thickness in an Iranian population sample

Background:

Considering that ethnicity and gestational age (GA) could affect the value of nuchal fold thickness (NFT) in mid-trimester, we aimed to determine the reference intervals of NFT values for each gestational week from 16 to 24 weeks of pregnancy among a group of Iranian pregnant women.

Materials and Methods:

In this cross-sectional study, medical files of pregnant women who underwent fetal anomaly scanning at 16–24 weeks of gestation were reviewed and the following data were extracted: GA, value of NFT, value of nuchal translucency (NT) in their previous ultrasound study, if available, and head circumference (HC). The 5^th, 25^th, 50^th, 75^th, and 95^th percentiles of NFT for each gestational week were determined. The association between NFT and HC, GA, and NT were also determined.

Results:

Medical files of 882 pregnant women were studied. The expected 95^th percentile value of NFT between 16^th and 24^th weeks of gestation ranged from 4 mm to 5.9 mm. The mean (standard deviation) of NFT increased with GA from 2.67 (0.90) mm at 16^th weeks to 4.69 (0.71) mm at 24^th weeks. There was a significant positive association between NFT and GA (β = 1.11, p < 0.001), HC (β = 0.21, p < 0.001), and NT (β = 0.351, p < 0.001).

Conclusion:

The findings of this study revealed that before the 20^th week of gestation, the appropriate cutoff value of NFT is 5 mm, and for 21^st to 24^th weeks, the proper cutoff is 6 mm. However, for providing more conclusive results, further studies with larger sample size and considering the impact of other influencing variables are recommended.

Trends in the use of prenatal testing services for fetal aneuploidy in Ontario: a descriptive study

BACKGROUND

In 2014, Ontario augmented its publicly funded multiple-marker screening program for prenatal aneuploidy by incorporating cell-free fetal DNA (cffDNA) analysis for high-risk pregnancies. We assessed trends in the use of multiple-marker screening, cffDNA screening and prenatal diagnostic testing before and after implementation of public funding.

METHODS

We conducted a descriptive study based on data from the Better Outcomes Registry & Network (BORN) Ontario. The study population included all pregnant women in Ontario with a singleton pregnancy and an expected date of delivery between July 1, 2012, and Mar. 31, 2016, with pregnancy data captured in BORN. Pregnancy losses and terminations before 20 weeks' gestation not captured in BORN were excluded. We generated descriptive statistics to show trends and regional variations in use.

RESULTS

The study sample included 534 210 singleton pregnancies. After cffDNA screening was funded for specific indications, uptake of multiple-marker screening increased slightly, from 66.5% to 68.1% (p < 0.001). Uptake of cffDNA screening among women with a positive multiple-marker screening result increased substantially, from 3.2% to 48.8% (p < 0.001). In contrast, the rate of prenatal diagnostic testing in this group decreased from 54.8% to 30.8% (p < 0.001). Although women aged 40 years or older are eligible for primary cffDNA screening, only a small decrease in the use of multiple-marker screening was observed in this group. The greatest use of cffDNA screening and greatest decline in prenatal diagnostic testing were seen in women with a level of risk for trisomy 21 of 1:101-1:200 based on multiple-marker screening.

INTERPRETATION

After public funding of cffDNA screening was implemented in Ontario, there was a significant increase in cffDNA screening and a significant decrease in prenatal diagnostic testing among women with a positive multiple-marker screening result. These changing patterns show the significant impact of public policy and funding decisions on women's choices regarding prenatal testing.

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.

Performance of prenatal screening using maternal serum and ultrasound markers for Down syndrome in Chinese women: a systematic review and meta-analysis

BACKGROUND

Controversies about the performance of conventional prenatal screening using maternal serum and ultrasound markers (PSMSUM) in detecting Down syndrome (DS) have been raised as a result of a recently available noninvasive prenatal test based on cell-free fetal DNA sequencing.

OBJECTIVES

To evaluate the screening performance of PSMSUM in detecting DS in Chinese women.

SEARCH STRATEGY

An exhaustive literature search of MEDLINE, Embase, the Cochrane Library, ISI Web of Science and China BioMedical Disc.

SELECTION CRITERIA

Primary studies, published from January 2004 to November 2014, which examined the screening accuracy of PSMSUM in pregnant Chinese women, compared with a reference standard, either chromosomal verification or inspection of the newborn.

DATA COLLECTION AND ANALYSIS

Data were extracted as screening positive/negative results for Down and non-Down syndrome pregnancies, allowing estimation of sensitivities and specificities. Risks of bias within and across studies were assessed. Screening accuracy measures were pooled using a bivariate random effects regression model.

MAIN RESULTS

Seventy-eight studies, involving six categories of PSMSUM, were included. Second-trimester double serum [pooled sensitivity (SEN) = 0.80, pooled specificity (SPE) = 0.95] and triple-serum (pooled SEN = 0.79, pooled SPE = 0.96) screening were the predominant PSMSUM methods. The screening performances of these methods achieved the national standard but varied enormously across studies. First-trimester combined screening (pooled SEN = 0.92, pooled SPE = 0.93) and second-trimester quadruple serum screening (median SEN = 0.86, median SPE = 0.96) performed better, but were rarely used.

AUTHOR'S CONCLUSIONS

Second-trimester maternal serum screening has the potential to achieve satisfactory screening performance in middle- and low-income countries. The reported enormous range in screening performance of second-trimester PSMSUM calls for urgent implementation of methods for performance optimization.

TWEETABLE ABSTRACT

Meta-analysis results show good accuracy of maternal serum and ultrasound screening for trisomy 21 in Chinese women.

N° 363 - Évaluation et prise en charge de l'anasarque fœtoplacentaire non immune

OBJECTIF

Décrire les méthodes actuelles d'évaluation et de prise en charge de l'anasarque fœtoplacentaire non immune en mettant l'accent sur les étiologies traitables ou récurrentes. RéSULTATS: Offrir de meilleurs services de conseil et de prise en charge en cas d'anasarque fœtoplacentaire non immune diagnostiquée en période prénatale. DONNéES: La littérature publiée a été récupérée au moyen de recherches menées dans PubMed, MEDLINE, CINAHL, et la Bibliothèque Cochrane en 2017 à l'aide de mots-clés (« non-immune hydrops fetalis », « fetal hydrops », « fetal therapy », « fetal metabolism »). Les articles retenus portaient sur des revues systématiques, des essais cliniques contrôlés, randomisés ou non, des études observationnelles et des études de cas importantes. D'autres publications ont été repérées dans les bibliographies de ces articles. Aucune restriction de date ou de langue n'a été employée. Les recherches ont été mis à jour régulièrement, et les résultats ont été incorporés à la directive clinique jusqu'en septembre 2017. Nous avons également tenu compte de la littérature grise (non publiée) trouvée sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes liés aux technologies de la santé, dans des collections de directives cliniques et des registres d'essais cliniques, et obtenue auprès d'associations nationales et internationales de médecins spécialistes. AVANTAGES, INCONVéNIENTS ET COûTS: La présente directive clinique renseigne les lecteurs sur les causes de l'anasarque fœtoplacentaire non immune ainsi que sur son évaluation et sa prise en charge. Elle propose également une approche standardisée d'évaluation et de prise en charge, et met l'accent sur la recherche des conditions traitables en période prénatale et des étiologies génétiques récurrentes.

VALEURS

La qualité des données probantes a été évaluée en fonction des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs. RECOMMANDATIONS.

Women's perspectives on the ethical implications of non-invasive prenatal testing: a qualitative analysis to inform health policy decisions

Background

Non-Invasive Prenatal Testing (NIPT) is a technology which provides information about fetal genetic characteristics (including sex) very early in pregnancy by examining fetal DNA obtained from a sample of maternal blood. NIPT is a morally complex technology that has advanced quickly to market with a strong push from industry developers, leaving many areas of uncertainty still to be resolved, and creating a strong need for health policy that reflects women’s social and ethical values. We approach the need for ethical policy-making by studying the use of NIPT and emerging policy in the province of Ontario, Canada.

Methods

Using an adapted version of constructivist grounded theory, we conducted interviews with 38 women who have had personal experiences with NIPT. We used an iterative process of data collection and analysis and a staged coding strategy to conduct a descriptive analysis of ethics issues identified implicitly and explicitly by women who have been affected by this technology.

Results

The findings of this paper focus on current ethical issues for women seeking NIPT, including place in the prenatal pathway, health care provider counselling about the test, industry influence on the diffusion of NIPT, consequences of availability of test results. Other issues gain relevance in the context of future policy decisions regarding NIPT, including funding of NIPT and principles that may govern the expansion of the scope of NIPT. These findings are not an exhaustive list of all the potential ethical issues related to NIPT, but rather a representation of the issues which concern women who have personal experience with this test.

Conclusions

Women who have had personal experience with NIPT have concerns and priorities which sometimes contrast dramatically with the theoretical ethics literature. These findings suggest the importance of engaging patients in ethical deliberation about morally complex technologies, and point to the need for more deliberative patient engagement work in this area.

Electronic supplementary material

The online version of this article (10.1186/s12910-018-0267-4) contains supplementary material, which is available to authorized users.

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.

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.

Nuchal translucency measurement, free β-hCG and PAPP-A concentrations in IVF/ICSI pregnancies: systematic review and meta-analysis

So far, data on the effect of assisted reproductive technologies (ART) on the components of first trimester combined screening for Down syndrome are still controversial. A systematic search of the literature was performed in order to identify the effect of ART, particularly in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with fresh embryo transfer, on the nuchal translucency, free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein-A measurements. Moreover, a meta-analysis and a descriptive graphical representation of the ratios between ART and spontaneous pregnancies (controls) values of median of the multiple of median (m₀ MoM) were performed. Free beta-human chorionic gonadotrophin test showed slightly higher values in the ICSI group than controls (RR = 1.09, 95%CI: 1.03-1.16) but not in the IVF group (RR = 1.03, 95%CI: 0.94-1.12). Pregnancy-associated plasma protein-A values for IVF/ICSI, IVF and ICSI showed lower values in comparison with controls (RR, 95%CI 0.85, 0.80-0.90; 0.82, 0.74-0.89 and 0.83, 0.79-0.86, respectively). The nuchal translucency measurement did not show any statistical differences between study groups (IVF and ICSI) and controls (RR = 1.00, 95%CI: 0.94-1.08 and RR = 1.01, 95%CI: 0.97-1.05, respectively). These results may be due to alterations in the placentation of ART pregnancies. Differentiating further subgroups of ART pregnancies may explain the differences in biomarker concentrations, in prenatal behavior and in obstetric outcomes between ART and spontaneous pregnancies. © 2017 John Wiley & Sons, Ltd.

Is there any relationship between low PAPP-A levels and measures of umbilical vein and placental thickness during first trimester of pregnancy?

OBJECTIVE

Low pregnancy-associated plasma protein A (PAPP-A) level is associated with adverse perinatal outcomes. The purpose of this study was to evaluate relationship between umbilical cord diameter (UCD), umbilical vein and artery diameters (UVD, UAD), placental thickness, and PAPP-A level at gestational age of between 11 and 14 weeks.

METHODS

UCD, UVD, UAD, and placental thickness of 246 women were assessed during ultrasound examination at between 11 and 14 weeks of gestation, as well as measurement of nuchal translucency (NT) and crown-rump length (CRL). Patients were divided into 2 groups according to PAPP-A percentile. Group 1 comprised 23 patients who had low PAPP-A (<0.44 multiple of medians [MoM], <10th percentile) and Group 2 was made up of 223 patients with PAPP-A of >0.44 MoM, >10th percentile. Calipers used for measurement were placed inner edge to inner edge of echogenic boundaries of the vessel. Largest sections of all vessels (UV and both arteries) were evaluated. Thickest part of the placenta was used for placental thickness measurement.

RESULTS

Narrow UCD (<4.5±0.6 mm) was associated with low PAPP-A level (p=0.02). There was no significant difference in UVD, UAD, or placental thickness between groups. There was no significant difference in gestational age, CRL, or NT between groups. Fetal birth weight was significantly lower in Group 1 (p=0.03).

CONCLUSION

Closer attention to women with low-risk, healthy pregnancies and low PAPP-A level in first trimester screening results is recommended. They should be routinely screened for background medical risk factors and umbilical cord morphology in first trimester scan.

Interventions et techniques de diagnostic prénatal visant l'obtention d'un prélèvement fœtal à des fins diagnostiques : Risques et avantages pour la mère et le fœtus

OBJECTIF

Offrir aux fournisseurs de soins de maternité et à leurs patientes des lignes directrices factuelles contemporaines en ce qui concerne les services de counseling traitant des risques et des avantages maternels propres à la tenue des interventions diagnostiques prénatales orientées par échographie (et/ou des techniques permettant l'établissement d'un diagnostic génétique) nécessaires dans les cas où il a été établi pendant la période prénatale que la grossesse serait exposée à des risques, ainsi qu'en ce qui concerne la prise de décisions subséquentes quant à la prise en charge de la grossesse (questions abordant des aspects tels que le niveau du fournisseur de soins obstétricaux, la surveillance prénatale, le lieu où devraient se dérouler les soins et l'accouchement, et la décision de poursuivre ou d'interrompre la grossesse). La présente directive clinique se limite aux services de counseling traitant des risques et des avantages maternels, et aux décisions en matière de prise en charge de la grossesse pour les femmes qui nécessitent (ou qui envisagent) la mise en œuvre d'une intervention ou d'une technique effractive orientée par échographie aux fins de l'établissement d'un diagnostic prénatal.

POPULATION DE PATIENTES

Femmes enceintes identifiées, à la suite de la mise en œuvre de protocoles établis de dépistage prénatal (taux sériques maternels ± imagerie, résultats d'analyse de l'ADN acellulaire indiquant des risques élevés, résultats anormaux au moment de l'imagerie fœtale diagnostique ou antécédents familiaux de troubles héréditaires), comme étant exposées à un risque accru d'anomalie génétique fœtale. Ces femmes pourraient nécessiter ou demander des services de counseling au sujet des risques et des avantages pour la grossesse de la tenue d'une intervention effractive orientée par échographie visant à déterminer l'étiologie, le diagnostic, et/ou la pathologie de possibles anomalies fœtales. RéSULTATS: La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans Medline, PubMed et The Cochrane Library jusqu'en juin 2014 au moyen d'un vocabulaire contrôlé (« prenatal diagnosis », « amniocentesis », « chorionic villi sampling », « cordocentesis ») et de mots clés (« prenatal screening », « prenatal genetic counselling », « post-procedural pregnancy loss rate ») appropriés. Les résultats ont été restreints aux analyses systématiques, aux études observationnelles et aux essais comparatifs randomisés / essais cliniques comparatifs publiés en anglais entre janvier 1985 et juin 2014. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'en juin 2014. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

La qualité des résultats a été évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau 1). AVANTAGES, DéSAVANTAGES ET COûTS: Consentement éclairé de la patiente, transfert des connaissances, évaluation du risque génétique prénatal, soulagement de l'anxiété, création d'anxiété, défense des droits, compréhension du dépistage fœtal, limites du dépistage fœtal, choix en matière de prise en charge de la grossesse, complication de la grossesse ou fausse couche, soins opportuns et améliorés pour l'accouchement d'un enfant présentant une morbidité reconnue. RECOMMANDATIONS.

Dosage of Sex Chromosomal Genes in Blood Deposited on Filter Paper for Neonatal Screening of Sex Chromosome Aneuploidy

AIMS

In this study, we examined the doses of the stature homeobox (SHOX), vesicle-associated membrane protein 7 (VAMP7), and SRY genes to establish a protocol for using peripheral blood samples deposited on filter paper for the screening of sex chromosome aneuploidy in neonates. We also measured correlations with karyotypes to assess this method as a neonatal screening strategy.

MATERIALS AND METHODS

This was an observational, descriptive, comparative blind study. Thirty-two healthy young adults (17 women, 15 men; age, ≥18 years), four patients with known sex chromosome aneuploidy (positive control group), and 1000 healthy newborns were included. Gene dosages were determined using quantitative real-time polymerase chain reaction (RT-PCR). Values with standard deviations (SDs) of three or more were considered abnormal.

RESULTS

Men and women differed in the gene dosage of the SRY gene. Cases with Turner syndrome showed values below 3 SDs for SHOX and VAMP7 genes, and cases with Klinefelter syndrome showed values above 3 SDs for SHOX and VAMP7 genes. Two suspected cases of sex chromosome aneuploidy were diagnosed using our neonatal screening strategy; these cases were confirmed as Turner syndrome and 47,XYY syndrome by karyotyping.

CONCLUSIONS

Our data establish a basis for the determination of chromosomal sex and neonatal screening of sex chromosome aneuploidy using RT-PCR.

Frequency of fetal karyotype abnormalities in women undergoing invasive testing in the absence of ultrasound and other high-risk indications

OBJECTIVES

No previous studies have reported the frequencies of individual chromosomal anomalies in normal-appearing fetuses stratified by maternal age (MA) and gestational age (GA). We therefore sought to (1) characterize the frequency of all fetal karyotype anomalies in sonographically normal appearing fetuses without pretest risk factors, and (2) assess MA and GA impact on the proportion of anomalies targeted by screening and consequent impact on residual risk following a negative result.

METHODS

Fetal karyotypes from samples without prior risk assessment or ultrasound anomalies were analyzed. We calculated, per single-year MA and in two GA intervals, the predicted frequency of each cytogenetic defect.

RESULTS

A total of 129 263 karyotypes were analyzed. The risk for significant, cytogenetically visible chromosomal anomalies, at 15 to 20 weeks GA, varies between 1/301 at MA of 18 years, and 1/9 at MA of 48 years. The proportion of clinically significant anomalies not addressed by current screening methods is 47% at MA of 18 years and 5% at MA of 48 years.

CONCLUSIONS

By determining frequencies for individual karyotype anomalies stratified by MA and GA, in the setting of normal-appearing fetuses, a more personalized risk assessment, including the residual risk after a normal fetal aneuploidy screening result, can be provided. © 2016 John Wiley & Sons, Ltd.

An update on current prenatal testing options: first trimester and noninvasive prenatal testing

Prenatal genetic testing is rapidly evolving and requires that prenatal care providers stay up-to-date with accurate, evidence-based knowledge. Noninvasive prenatal testing (NIPT), first trimester maternal serum markers, and fetal nuchal translucency are the most recently developed screening tests added to the testing repertoire for detection of chromosomal disorders such as trisomy 21 (Down syndrome). NIPT is a new, highly accurate technique that uses maternal serum and is rapidly being introduced as a first trimester screening tool and increasingly being requested by pregnant women. The American College of Obstetricians and Gynecologists recommends that all pregnant women be offered first and second trimester screening options, regardless of risk status, but does not yet recommend NIPT. It is important for prenatal care providers to be aware of and understand these testing options in order to assist women and their families in making well-informed decisions during pregnancy. The purpose of this article is to update midwives and other prenatal care providers on the current prenatal genetic testing options available and how to appropriately offer and discuss them with their clients. We discuss how these tests work; what to do with the results; and most importantly, how to support and communicate accurate information to women and families as they navigate through an increasingly complicated array of testing choices.

Analysis of first-trimester combined test results in preparation for a cell-free fetal DNA era

OBJECTIVE

To survey experience with the first-trimester combined test (FCT) for trisomy 21 (T21) in different risk score groups to determine the most useful clinical application of cell-free fetal DNA (cffDNA) screening.

METHODS

In a retrospective study, the records of FCT results obtained at a center in Turkey between January 2009 and January 2014 were reviewed. The FCT results and rates of uptake of invasive diagnostic testing were compared among different risk score groups.

RESULTS

FCT results were available for 4804 pregnancies; 276 (5.7%) had IDT results. Ten (72.7%) of 11 cases of T21 had a risk score of 1:300 or more. The IDT uptake rates were 54.5%, 51.9%, and 47.4% at risk scores of 1:100 or more, 1:200 or more, and 1:300 or more, respectively. In the group at intermediate risk (1:1001-1:3000), no pregnancy had an FCT result of both low pregnancy-associated plasma protein A and high free β-human chorionic gonadotropin, but 30 (3.9%) of 766 pregnancies had both advanced maternal age and high β-human chorionic gonadotropin.

CONCLUSION

cffDNA screening should be used to optimize IDT uptake in pregnancies with a risk score of 1:101-1:1000. The selective power of the FCT diminishes beyond the 1:1001 score and cffDNA screening cannot yet be recommended routinely.

Canadian women's attitudes toward noninvasive prenatal testing of fetal DNA in maternal plasma (.)

OBJECTIVE

To determine the perceptions and attitudes of Canadian women to Noninvasive Prenatal Testing of fetal DNA.

STUDY DESIGN

A designed questionnaire was administered to women attending the outpatient antenatal clinic at a tertiary urban hospital. Attitudes to current and new prenatal screening modalities were assessed using a five-point Likert scale. Bowker's test of symmetry was used to compare individual responses regarding the two screening modalities. Changes in women's responses pre- and post-delivery were also compared.

RESULTS

One hundred and twenty-nine women were enrolled in this study. 88% of women state that they would perform prenatal screening via fetal DNA in the maternal plasma if available. When compared to conventional screening, significantly less women believe that the NIPT should be available upon request for non-medical traits (36.4% versus 60.4%, p < 0.001). When compared to their answer before delivery, more women agreed that screening with fetal DNA in maternal plasma could be used in a negative way to select for desired non-medical traits such as gender.

CONCLUSIONS

The use of fetal DNA in the maternal plasma is widely accepted in our Canadian population as a future method of noninvasive prenatal screening despite recognition of certain ethical concerns. This information can be used when implementing new genetic screening programs.

Anatomical and clinical aspects of Klinefelter's syndrome

Klinefelter's syndrome, the most common sex disorder associated with chromosomal aberrations, is characterized by a plethora of clinical features. Parameters for diagnosis of the syndrome are constantly expanding as new anatomical and hormonal abnormalities are noted, yet Klinefelter's remains underdiagnosed and underreported. This review outlines the key anatomical characteristics associated with the syndrome, which are currently used for clinical diagnosis, or may provide means for improving diagnosis in the future. Clin. Anat. 29:606-619, 2016. © 2016 Wiley Periodicals, Inc.

Non-invasive prenatal testing for fetal chromosome abnormalities: review of clinical and ethical issues

Genomics-based non-invasive prenatal screening using cell-free DNA (cfDNA screening) was proposed to reduce the number of invasive procedures in current prenatal diagnosis for fetal aneuploidies. We review here the clinical and ethical issues of cfDNA screening. To date, it is not clear how cfDNA screening is going to impact the performances of clinical prenatal diagnosis and how it could be incorporated in real life. The direct marketing to users may have facilitated the early introduction of cfDNA screening into clinical practice despite limited evidence-based independent research data supporting this rapid shift. There is a need to address the most important ethical, legal, and social issues before its implementation in a mass setting. Its introduction might worsen current tendencies to neglect the reproductive autonomy of pregnant women.

The endocrine function of human placenta: an overview

During pregnancy, several tightly coordinated and regulated processes take place to enable proper fetal development and gestational success. The formation and development of the placenta is one of these critical pregnancy events. This organ plays essential roles during gestation, including fetal nourishment, support and protection, gas exchange and production of several hormones and other mediators. Placental hormones are mainly secreted by the syncytiotrophoblast, in a highly and tightly regulated way. These hormones are important for pregnancy establishment and maintenance, exerting autocrine and paracrine effects that regulate decidualization, placental development, angiogenesis, endometrial receptivity, embryo implantation, immunotolerance and fetal development. In addition, because they are released into maternal circulation, the profile of their blood levels throughout pregnancy has been the target of intense research towards finding potential robust and reliable biomarkers to predict and diagnose pregnancy-associated complications. In fact, altered levels of these hormones have been associated with some pathologies, such as chromosomal anomalies or pre-eclampsia. This review proposes to revise and update the main pregnancy-related hormones, addressing their major characteristics, molecular targets, function throughout pregnancy, regulators of their expression and their potential clinical interest.

Outcomes of pregnancies with more than one positive prenatal screening result in the first or second trimester

OBJECTIVE

To describe adverse outcomes and fetal abnormalities in women with a positive prenatal screening result for more than one disorder.

STUDY DESIGN

Study participants were drawn from a population of 452 901 women pregnant with singletons entering the California Prenatal Screening Program in their first-trimester. Risk assessment was provided for trisomy 21 and trisomy 18 in the first-trimester and trisomy 21, trisomy 18, neural tube defects, and Smith-Lemli-Opitz syndrome in the second-trimester. Inclusion in this study required positive screening for more than one of the screened conditions and a completed outcome of pregnancy survey.

RESULTS

A total of 874 women met our study inclusion criteria. Over 25% of these pregnancies had a fetus with a chromosomal abnormality. Of the euploid pregnancies, 6.9% had a fetus with a major birth defect. Of the pregnancies with a fetus with neither a chromosomal abnormality nor a major birth defect, 9.3% ended in fetal demise. Overall, more than 50% of women with multiple positive screening results had either a fetus with a birth defect or a poor pregnancy outcome.

CONCLUSION

Although it is rare to screen positive for more than one condition, such results indicate a very high risk for chromosomal abnormality, fetal demise, or structural abnormality.