Prenatal screening for fetal aneuploidy in singleton pregnancies

Factors Affecting Improved Prenatal Screening: A Narrative Review

Background:

Prenatal screening deals with the detection of structural and functional abnormalities in the fetus. Health care providers can minimize unintended pregnancy outcomes by providing proper counseling and performing prenatal screening. The purpose of the present review study is to investigate factors affecting improved prenatal screening.

Methods:

The present study is a narrative review searching public databases such as Google Scholar and specialized databases such as Pubmed, Magiran, Scientific Information Database, Elsevier, Ovid and Science Direct as well. Using the keywords “prenatal screening”, “fetus health” and “prenatal counseling”, 70 relevant articles published from 1994 to 2014 were selected. After reviewing the abstracts, the full data from 26 articles were ultimately used for writing the present review study.

Results:

Three general themes emerged from reviewing the studies: health care providers’ skills, clients’ characteristics and ethical considerations, which were the main factors affecting improved prenatal screening.

Conclusion:

Prenatal screening can be successful if performed by a trained and experienced expert through techniques suitable for the mother’s age. Also simultaneously providing proper counseling and giving a full description of the risks and benefits of the procedures for clients is recommended.

Decision aids that support decisions about prenatal testing for Down syndrome: an environmental scan

BACKGROUND

Prenatal screening tests for Down syndrome (DS) are routine in many developed countries and new tests are rapidly becoming available. Decisions about prenatal screening are increasingly complex with each successive test, and pregnant women need information about risks and benefits as well as clarity about their values. Decision aids (DAs) can help healthcare providers support women in this decision. Using an environmental scan, we aimed to identify publicly available DAs focusing on prenatal screening/diagnosis for Down syndrome that provide effective support for decision making.

METHODS

Data sources searched were the Decision Aids Library Inventory (DALI) of the Ottawa Patient Decision Aids Research Group at the Ottawa Health Research Institute; Google searches on the internet; professional organizations, academic institutions and other experts in the field; and references in existing systematic reviews on DAs. Eligible DAs targeted pregnant women, focused on prenatal screening and/or diagnosis, applied to tests for fetal abnormalities or aneuploidies, and were in French, English, Spanish or Portuguese. Pairs of reviewers independently identified eligible DAs and extracted characteristics including the presence of practical decision support tools and features to aid comprehension. They then performed quality assessment using the 16 minimum standards established by the International Patient Decision Aids Standards (IPDASi v4.0).

RESULTS

Of 543 potentially eligible DAs (512 in DALI, 27 from experts, and four on the internet), 23 were eligible and 20 were available for data extraction. DAs were developed from 1996 to 2013 in six countries (UK, USA, Canada, Australia, Sweden, and France). Five DAs were for prenatal screening, three for prenatal diagnosis and 12 for both). Eight contained values clarification methods (personal worksheets). The 20 DAs scored a median of 10/16 (range 6-15) on the 16 IPDAS minimum standards.

DISCUSSION

None of the 20 included DAs met all 16 IPDAS minimum standards, and few included practical decision support tools or aids to comprehension.

CONCLUSIONS

Our results indicate there is a need for DAs that effectively support decision making regarding prenatal testing for Down syndrome, especially in light of the recently available non-invasive prenatal screening tests.

Women's Experiences of Publicly Funded Non-Invasive Prenatal Testing in Ontario, Canada: Considerations for Health Technology Policy-Making

Non-invasive prenatal testing (NIPT) via fetal DNA in maternal blood has been publicly funded in Ontario, Canada, for high-risk women since 2014. We solicited women's experiences and values related to this new health technology to describe how this test is currently being used in Ontario and to provide information about patient priorities to inform future policy decisions about the use of NIPT. Guided by constructivist grounded theory methodology, we interviewed 38 women who had diverse personal experiences with NIPT. Participants' accounts of their values for decision making about NIPT heavily relied on three mutually modulating factors: timing, accuracy, and risk. The values expressed by women conflict with the way that publicly funded NIPT has typically been implemented in Ontario. We offer recommendations for how NIPT might be integrated into prenatal care pathways in a way more consistent with women's values.

Rates of prenatal screening across health care regions in Ontario, Canada: a retrospective cohort study

BACKGROUND

It is recommended that all pregnant women be offered screening for Down syndrome and open neural tube defects, but emerging prenatal tests that are not publicly insured may compromise access. We evaluated screening rates for publicly insured screening tests across health care regions in the province of Ontario and determined whether maternal, provider or regional characteristics are associated with screening uptake.

METHODS

We conducted a population-based retrospective cohort study involving pregnant women in Ontario who were at or beyond 16 weeks' gestation in 2007-2009. We ascertained prenatal screening rates using linked health administrative and prenatal screening datasets. We examined maternal, provider and regional characteristics associated with screening uptake. Rate ratios (RRs) were estimated.

RESULTS

Of the 264 737 women included in the study, 62.2% received prenatal screening; uptake varied considerably by region (range 27.8%-80.3%). A greater proportion of women initiated screening in the first rather than the second trimester (50.0% v. 12.2%). Factors associated with lower screening rates included living in a rural area versus an urban area (adjusted rate ratio 0.64, 95% confidence interval [CI] 0.63-0.66), receiving first-trimester care from a family physician or midwife versus an obstetrician (adjusted rate ratio 0.91, 95% CI 0.90-0.92, and 0.40, 95% CI 0.38-0.43, respectively) and being in a lower income quintile (adjusted RR for lowest v. highest 0.95, 95% CI 0.94-0.96). Being an immigrant or a refugee was associated with higher screening rates.

INTERPRETATION

There were significant maternal, provider and regional differences in the uptake of prenatal screening across the province. With discrepancies expected to increase with the emergence of noninvasive prenatal tests paid for out of pocket by many women, policy efforts to reduce barriers to prenatal screening and optimize its availability are warranted.

Introducing the non-invasive prenatal test for trisomy 21 in Belgium: a cost-consequences analysis

BACKGROUND

The first- and second-trimester screening for trisomy 21 (T21) are reimbursed for all pregnant women in Belgium. Using a cut-off risk of 1:300 for T21, about 5% of all pregnant women are referred for definitive prenatal diagnosis using an invasive test, at a sensitivity of (only) 72.5%. The sensitivity and specificity of the non-invasive prenatal test (NIPT) are over 99% but come at a cost of €460 (£373) per test. The objective is to estimate the consequences of introducing NIPT for the detection of T21.

METHODS

A cost-consequences analysis was performed presenting the impact on benefits, harms and costs. Context-specific real-world information was available to set up a model reflecting the current screening situation in Belgium. This model was used to construct the second and first line NIPT screening scenarios applying information from the literature on NIPT's test accuracy.

RESULTS

Introducing NIPT in the first or second line reduces harm by decreasing the number of procedure-related miscarriages after invasive testing. In contrast with NIPT in the second line, offering NIPT in the first line additionally will miss fewer cases of T21 due to less false-negative test results. The introduction of NIPT in the second line results in cost savings, which is not true for NIPT at the current price in the first line. If NIPT is offered to all pregnant women, the price should be lowered to about €150 to keep the screening cost per T21 diagnosis constant.

CONCLUSIONS

In Belgium, the introduction and reimbursement of NIPT as a second line triage test significantly reduces procedure-related miscarriages without increasing the short-term screening costs. Offering and reimbursing NIPT in the first line to all pregnant women is preferred in the long term, as it would, in addition, miss fewer cases of T21. However, taking into account the government's limited resources for universal reimbursement, the price of NIPT should first be lowered substantially before this can be realised.

Non-invasive prenatal testing: ethics and policy considerations

New technologies analyzing fetal DNA in maternal blood have led to the wide commercial availability of non-invasive prenatal testing (NIPT). We present here for clinicians the ethical and policy issues related to an emerging practice option. Although NIPT presents opportunities for pregnant women, particularly women who are at increased risk of having a baby with an abnormality or who are otherwise likely to access invasive prenatal testing, NIPT brings significant ethics and policy challenges. The ethical issues include multiple aspects of informed decision-making, such as access to counselling about the possible results of the test in advance of making a decision about participation in NIPT. Policy considerations include issues related to offering and promoting a privately available medical strategy in publicly funded institutions. Ethics and policy considerations merge in NIPT with regard to sex selection and support for persons living with disabilities.

The portrayal of Down syndrome in prenatal screening information pamphlets

OBJECTIVE

To examine the information about Down syndrome (DS) provided to pregnant women in Canada through a content analysis of prenatal screening information pamphlets.

METHODS

Prenatal screening information pamphlets were requested from Canadian prenatal testing centres. In total, 17 pamphlets were received (response rate = 65%). Statements presenting information descriptive of DS were identified from the pamphlets, and a content analysis was carried out. Specifically, each statement was analyzed with respect to both the content and the valence of the information presented on the basis of predetermined decision rules. To enhance reliability, four independent raters reviewed each statement, and any differences in coding were resolved through discussion.

RESULTS

In total, 158 statements descriptive of DS were extracted from the pamphlets. The categorical analysis revealed that 91% of the extracted statements emphasized medical or clinical information about DS, whereas only 9% of the statements relayed information pertaining to psychosocial issues. The valence analysis revealed that nearly one half of the statements portrayed a negative message pertaining to DS, while only 2.4% of the statements conveyed a positive image of DS.

CONCLUSION

The pamphlets provided to pregnant women do not appear to present a comprehensive, balanced portrayal of DS, which may serve to limit informed decision-making.

Identification of trisomy 18, trisomy 13, and Down syndrome from maternal plasma

Current prenatal diagnosis for fetal aneuploidies (including trisomy 21 [T21]) generally relies on an initial biochemical serum-based noninvasive prenatal testing (NIPT) after which women who are deemed to be at high risk are offered an invasive confirmatory test (amniocentesis or chorionic villi sampling for a fetal karyotype), which is associated with a risk of fetal miscarriage. Recently, genomics-based NIPT (gNIPT) was proposed for the analysis of fetal genomic DNA circulating in maternal blood. The diffusion of this technology in routine prenatal care could be a major breakthrough in prenatal diagnosis, since initial research studies suggest that this novel approach could be very effective and could reduce substantially the number of invasive procedures. However, the limitations of gNIPT may be underappreciated. In this review, we examine currently published literature on gNIPT to highlight advantages and limitations. At this time, the performance of gNIPT is relatively well-documented only in high-risk pregnancies for T21 and trisomy 18. This additional screening test may be an option for women classified as high-risk of aneuploidy who wish to avoid invasive diagnostic tests, but it is crucial that providers carefully counsel patients about the test's advantages and limitations. The gNIPT is currently not recommended as a first-tier prenatal screening test for T21. Since gNIPT is not considered as a diagnostic test, a positive gNIPT result should always be confirmed by an invasive test, such as amniocentesis or chorionic villus sampling. Validation studies are needed to optimally introduce this technology into the existing routine workflow of prenatal care.

Prenatal diagnosis versus first-trimester screening of trisomy 21 among pregnant women aged 35 or more

OBJECTIVE

To compare the policy of prenatal diagnosis versus first trimester screening of trisomy 21 among pregnant women of advanced age.

METHODS

A retrospective study was conducted on patients aged ≥35 divided in two groups: patients who requested first trimester combined test and only in case of screen-positive result underwent invasive testing (group A); patients undergoing chorionic villous sampling or amniocentesis as first investigation (group B). The following outcome variables were compared: antenatal detection of trisomy 21, occurrence of trisomy 21 at birth, miscarriage rate, hospitals' costs.

RESULTS

4527 women were included. Of these, 534 (11.80%) underwent T21 screening whereas 3993 (88.20%) requested primary invasive testing. In group A, 64 combined test were positive (11.99%) and 8 trisomy 21 cases were diagnosed (1.50%); the loss of euploid fetuses after invasive procedure was 4.55% (2/44). No false-negative case was observed. In group B 57 cases of trisomy 21 were diagnosed (1.43%), and pregnancy loss rate of chromosomally normal fetuses was 0.45% (17/3806). The estimated cost was, respectively, 67.720€ for the primary screening versus 1.996.500€ for direct prenatal diagnosis.

CONCLUSION

First trimester screening of trisomy 21 is highly accurate and cost saving among women ≥35.

QF-PCR rapid aneuploidy screen and aCGH analysis of cell free fetal (cff) DNA in supernatant of compromised amniotic fluids (AF)

OBJECTIVE

The aim of this study was to determine whether cell free fetal (cff) DNA in residual amniotic fluid (AF) supernatant obtained from bloody, low-volume and late gestation samples can be used for prenatal diagnosis by quantitative fluorescence polymerase chain reaction (QF-PCR) and array comparative genomic hybridization (aCGH).

METHOD

A total of 49 compromised AFs were analyzed in this case-control, double-blinded study. The samples were processed through: a conventional cytogenetic approach utilizing Fluorescence in situ Hybridization and/or karyotype (Approach I); QF-PCR analysis to establish the presence of maternal cell contamination (MCC) (Approach II) and a newly proposed approach using AF supernatant cff DNA (Approach III). Data on clinical impact and turn-around-time was collected.

RESULTS

Evidence of MCC was not detected in any of the cff DNA samples, and informative results were provided for all cases, including nine aneuploidies. In contrast, the conventional approach (I) failed to provide results either due to MCC or culture failure in a significant proportion of cases. An adequate amount of quality cff DNA was obtained for successful aCGH testing.

CONCLUSION

We have shown that it is feasible to isolate pure cff DNA from routinely discarded AF supernatant to perform QF-PCR and microarray analyses, providing timely and informative results even for problematic grossly bloody and otherwise compromised AF samples or culture failures.

Obstetric, perinatal, and fetal outcomes in pregnancies with false-positive integrated screening results

OBJECTIVE

To assess the risk of adverse obstetric, perinatal, and fetal outcomes for pregnant women participating in prenatal sequential integrated screening through the California Prenatal Screening Program who had a false-positive screening result.

METHODS

Women who underwent first- and second-trimester prenatal integrated screening plus nuchal translucency measurement with outcome information available were included. Fetuses and neonates with chromosomal or neural tube defects were excluded. We compared the risk of adverse outcomes for all women with a positive screening result compared with a 10% random sample of women with a negative screening result. Logistic binomial regression was used to compare adverse outcomes in screen-positive compared with screen-negative women.

RESULTS

We identified 9,051 screen-positive and 30,928 screen-negative pregnancies with outcome information available. Compared with screen-negative pregnancies, screen-positive women were more likely to be diagnosed with preeclampsia, placenta previa, or abruption (7.6% screen-positive, 3.8% screen-negative; relative risk 1.7, 95% confidence interval [CI] 1.6-1.8) or experience fetal loss before 20 weeks of gestation (1.9% screen-positive, 0.2% screen-negative; relative risk 3.5, 95% CI 3.2-3.8). Women with positive results for more than one screened condition were at substantially greater risk of fetal and neonatal mortality (relative risks 33.6-156.7, 95% CIs 21.8-194.4).

CONCLUSION

Among pregnancies without chromosomal or neural tube defects, prenatal sequential integrated screening provides information regarding risk across a variety of adverse pregnancy outcomes.

Beyond Trisomy 21: Additional Chromosomal Anomalies Detected through Routine Aneuploidy Screening

Prenatal screening is often misconstrued by patients as screening for trisomy 21 alone; however, other chromosomal anomalies are often detected. This study aimed to systematically review the literature and use diagnostic meta-analysis to derive pooled detection and false positive rates for aneuploidies other than trisomy 21 with different prenatal screening tests. Non-invasive prenatal testing had the highest detection (DR) and lowest false positive (FPR) rates for trisomy 13 (DR: 90.3%; FPR: 0.2%), trisomy 18 (DR: 98.1%; FPR: 0.2%), and 45,X (DR: 92.2%; FPR: 0.1%); however, most estimates came from high-risk samples. The first trimester combined test also had high DRs for all conditions studied (trisomy 13 DR: 83.1%; FPR: 4.4%; trisomy 18 DR: 91.9%; FPR: 3.5%; 45,X DR: 70.1%; FPR: 5.4%; triploidy DR: 100%; FPR: 6.3%). Second trimester triple screening had the lowest DRs and highest FPRs for all conditions (trisomy 13 DR: 43.9%; FPR: 8.1%; trisomy 18 DR: 70.5%; FPR: 3.3%; 45,X DR: 77.2%; FPR: 9.3%). Prenatal screening tests differ in their ability to accurately detect chromosomal anomalies. Patients should be counseled about the ability of prenatal screening to detect anomalies other than trisomy 21 prior to undergoing screening.

Are midwifery clients in Ontario making informed choices about prenatal screening?

BACKGROUND

Informed choice is often lacking in women's decisions about prenatal screening.

AIM

The aim of this study is to evaluate how well midwives in Ontario, Canada are facilitating informed choice in this area.

METHODS

An Internet-based survey was used to investigate 171 midwifery clients' knowledge, attitude towards and experience of prenatal genetic screening tests, and to determine the proportion of study participants who made an informed choice about prenatal screening.

FINDINGS

All participants demonstrated adequate knowledge of prenatal screening. The vast majority (93.0%) of participants made an informed choice. Participants who chose to screen had lower knowledge scores than those who opted out of screening. Client satisfaction rates in regard to care received in this area ranged from 97% to 100%.

CONCLUSIONS

Results of this study suggest that Ontario midwives are effective in conveying information on prenatal genetic screening, contributing to high levels of client knowledge and satisfaction in comparison to similar studies in other jurisdictions.

The price of performance: a cost and performance analysis of the implementation of cell-free fetal DNA testing for Down syndrome in Ontario, Canada

OBJECTIVE

To examine the cost and performance implications of introducing cell-free fetal DNA (cffDNA) testing within modeled scenarios in a publicly funded Canadian provincial Down syndrome (DS) prenatal screening program.

METHOD

Two clinical algorithms were created: the first to represent the current screening program and the second to represent one that incorporates cffDNA testing. From these algorithms, eight distinct scenarios were modeled to examine: (1) the current program (no cffDNA), (2) the current program with first trimester screening (FTS) as the nuchal translucency-based primary screen (no cffDNA), (3) a program substituting current screening with primary cffDNA, (4) contingent cffDNA with current FTS performance, (5) contingent cffDNA at a fixed price to result in overall cost neutrality,(6) contingent cffDNA with an improved detection rate (DR) of FTS, (7) contingent cffDNA with higher uptake of FTS, and (8) contingent cffDNA with optimized FTS (higher uptake and improved DR).

RESULTS

This modeling study demonstrates that introducing contingent cffDNA testing improves performance by increasing the number of cases of DS detected prenatally, and reducing the number of amniocenteses performed and concomitant iatrogenic pregnancy loss of pregnancies not affected by DS. Costs are modestly increased, although the cost per case of DS detected is decreased with contingent cffDNA testing.

CONCLUSION

Contingent models of cffDNA testing can improve overall screening performance while maintaining the provision of an 11- to 13-week scan. Costs are modestly increased, but cost per prenatally detected case of DS is decreased.

Influence of qualitative research on women's health screening guidelines

OBJECTIVE

Considerable time and resources are allocated to carry out qualitative research. The purpose of our study was to evaluate the availability of qualitative research on women's health screening and assess its influence on screening practice guidelines in the United States, Canada, and the United Kingdom.

STUDY DESIGN

Medline, CINHAL, and WEB of Science databases were used to identify the availability of qualitative research conducted in the past 15 years on 3 different women's health screening topics: cervical cancer screening, breast cancer screening, and prenatal first-trimester screening. Key national practice guidelines on women's health screening were selected using the National Guideline Clearinghouse web site. Bibliometric analysis was used to determine the frequency of qualitative references cited in the guidelines.

RESULTS

A total of 272 qualitative research papers on women's health screening was identified: 109 on cervical cancer screening, 104 on breast cancer screening, and 59 on prenatal first-trimester screening. The qualitative studies focused on health care provider perspectives as well as ethical, ethnographic, psychological, and social issues surrounding screening. Fifteen national clinical practice guidelines on women's health screening were identified. A total of 943 references was cited, only 2 of which comprised of qualitative research cited by only 1 clinical practice guideline.

CONCLUSION

Although there is considerable qualitative research that has been carried out on women's health screening, its incorporation into clinical practice guidelines is minimal. Further exploration of the disconnect between the two is important for enhancing knowledge translation of qualitative research within clinical practice.

Follow-up of sonographically detected soft markers for fetal aneuploidy

Sonographic soft markers of fetal Down syndrome were first reported in the 1980s. With improvements in aneuploidy screening, detection rates of 90% and higher are possible, and such screening is offered to women of all ages. The utility of sonographic detection and reporting of soft markers, particularly to women at low risk of fetal aneuploidy, is controversial. Some soft markers have no additional significance beyond an association with aneuploidy, while some potentially indicate other pathology, and therefore require sonographic follow-up or other evaluation. The definitions of soft markers vary among reported series, and any practice using such markers to adjust the risk of aneuploidy should carefully determine the most appropriate definitions as well as likelihood ratios and how to apply these in practice.

Assessing the impact of the SOGC recommendations to increase access to prenatal screening on overall use of health resources in pregnancy

OBJECTIVES

The recommendation by the Society of Obstetricians and Gynaecologists of Canada that prenatal screening for fetal aneuploidy be offered to all pregnant women is an important change in clinical obstetrics. However, it is unknown how this recommendation might affect the use of other health resources during pregnancy.

METHODS

Twelve clinical and administrative databases were linked, and care paths outlining typical service use in pregnancy were created based on the type of prenatal screening accessed (first trimester screening [FTS], maternal serum screening [MSS], invasive testing only, or no screening and/or diagnosis). Logistic, Poisson, and negative binomial models were applied to the data to examine the association between use of prenatal screening/diagnosis and other health services during pregnancy.

RESULTS

Women who accessed prenatal screening/diagnosis were significantly more likely to have a consultation with a medical geneticist (FTS OR 2.42; 95% CI 1.75 to 3.33; MSS OR 4.84; 95% CI 2.92 to 8.03; and invasive testing OR 8.58; 95% CI 5.28 to 13.94), and women who accessed FTS had more prenatal visits (FTS incidence rate ratio 1.03; 95% CI 1.01 to 1.05) than women who did not access prenatal screening/diagnosis. Uptake of invasive tests did not differ between women who accessed FTS and those who accessed MSS. Use of prenatal screening/diagnosis was not significantly associated with use of most other health resources

CONCLUSION

In a publicly funded health care system, understanding the impact of recommendations to increase access to a specific service on other services is important. Recommendations to increase access to prenatal screening services may have some unanticipated downstream effects on the use of other services during pregnancy. However, most aspects of health resource use in pregnancy do not appear to be influenced by the use of prenatal screening services.

A systematic review of factors influencing uptake of invasive fetal genetic testing by pregnant women of advanced maternal age

Women of advanced maternal age have a higher risk of having a child affected by a chromosomal disorder than younger childbearing women and are frequently offered invasive testing during pregnancy. The aim of our systematic review was to identify and analyse the current evidence base regarding factors that influence the uptake of invasive fetal testing by pregnant women of advanced maternal age. We conducted a systematic review. A search of The Cochrane Library, CINAHL, Embase and Medline databases was undertaken for papers published in English and Italian from January 2002 to May 2012. Eleven studies satisfied the inclusion criteria, were subjected to quality assessment and included in the review. We analysed the data using thematic analysis. The factors influencing women were classified as either external or psychosocial factors. External factors included the opportunity for screening, screening results and use of genetic counselling. Psychosocial factors related to ethnicity, socio-demographic status and attendance of partners during counselling. It is difficult to draw firm conclusions as to the principle factors that influence uptake of invasive tests by women of AMA. More research is needed to enhance understanding of relevant factors to ensure that services are offered in a way that acknowledges practical as well as psychosocial influences. This type of research will help to equip midwives and other professionals caring for women during pregnancy to ensure that women are supported to make the choices that are appropriate for them and their families.

Counselling considerations for prenatal genetic screening

This document has been developed to aid clinicians in counselling patients about prenatal screening and to provide assistance in counselling about both positive and negative screening results.

Pregnancy and delivery outcomes following a pathological second trimester triple test screening result and a normal karyotype

OBJECTIVE

To investigate whether obstetrical complications are increased in pregnancies with a normal karyotype and an abnormal triple test (TT) (≥1:380 or more) where all analytes were within the normal range.

METHODS

A retrospective cohort study of women who underwent a TT and delivered in a tertiary medical center, was conducted. Patients were divided into a study group (pregnancies with abnormal TT) and a control group (normal TT). In both groups, the analyte concentrations were within the normal range and the karyotype was normal. Demographic and clinical characteristics, antenatal factors, gestational complications and perinatal outcomes were compared between the groups.

RESULTS

An abnormal TT result in the presence of normal analytes and a normal karyotype, had no impact on obstetrical complications. A direct association between elevated values of hCG within the normal range (0-2.0 MoM) and pathological TT was noticed (OR = 2.6, p < 0.01). On the other hand, an inverse correlation between elevation in AFP (0-2.0 MoM) and uE3 was found (OR < 0.01, p < 0.01; OR < 0.01, p < 0.01, respectively).

CONCLUSIONS

An abnormal TT result in the presence of normal analytes and a normal karyotype, had no influence on rate of obstetrical complications.

Prenatal testing for Down syndrome: the perspectives of parents of individuals with Down syndrome

This exploratory, descriptive study examined the views and opinions of parents of individuals with Down syndrome (DS) related to prenatal testing for DS and the use of age-based criteria to determine eligibility for this testing. This survey-based study was designed in collaboration with parents of individuals with DS and the British Columbia-based Lower Mainland Down Syndrome Society (LMDSS). The survey was a 26-item, self-report questionnaire, which was distributed by the LMDSS. Out of the 246 potentially eligible individuals that were mailed surveys, 101 participants returned their completed surveys. The availability of prenatal screening and diagnostic testing for DS was perceived positively by 55.1% and 64.7% of parents, respectively. More than half (60.2%) of participants felt that prenatal diagnostic testing for DS should be available to all pregnant women, regardless of age. In this study, views of Canadian parents of individuals with DS aligned with the prenatal testing policy recently adopted in the USA (whereby any woman, regardless of age or risk factors, can opt for prenatal diagnostic testing) rather than with new Canadian policy (whereby eligibility for diagnostic testing is no longer offered on the basis of age, but on the basis of other risk factors).