Women's opinions and the implications of first- versus second-trimester screening for fetal Down's syndrome

Psychological outcomes, knowledge and preferences of pregnant women on first-trimester screening for fetal structural abnormalities: A prospective cohort study

INTRODUCTION

The primary aim of this study is to investigate the impact of a 13-week anomaly scan on the experienced levels of maternal anxiety and well-being. Secondly, to explore women's knowledge on the possibilities and limitations of the scan and the preferred timing of screening for structural abnormalities.

MATERIAL AND METHODS

In a prospective-cohort study conducted between 2013-2015, pregnant women in the North-Netherlands underwent a 13-week anomaly scan. Four online-questionnaires (Q1, Q2, Q3 and Q4) were completed before and after the 13- and the 20-week anomaly scans. In total, 1512 women consented to participate in the study and 1118 (74%) completed the questionnaires at Q1, 941 (64%) at Q2, 807 (55%) at Q3 and 535 (37%) at Q4. Psychological outcomes were measured by the state-trait inventory-scale (STAI), the patient's positive-negative affect (PANAS) and ad-hoc designed questionnaires.

RESULTS

Nine-nine percent of women wished to be informed as early as possible in pregnancy about the absence/presence of structural abnormalities. In 87% of women levels of knowledge on the goals and limitations of the 13-week anomaly scan were moderate-to-high. In women with a normal 13-week scan result, anxiety levels decreased (P < .001) and well-being increased over time (P < .001). In women with false-positive results (n = 26), anxiety levels initially increased (STAI-Q1: 39.8 vs. STAI-Q2: 48.6, P = 0.025), but later decreased around the 20-week anomaly scan (STAI-Q3: 36.4 vs. STAI-Q4: 34.2, P = 0.36).

CONCLUSIONS

The 13-week scan did not negatively impact the psychological well-being of pregnant women. The small number of women with screen-positive results temporarily experienced higher anxiety after the scan but, in false-positive cases, anxiety levels normalized again when the abnormality was not confirmed at follow-up scans. Finally, most pregnant women have moderate-to-high levels of knowledge and strongly prefer early screening for fetal structural abnormalities.

Prenatal Screening, Ethics and Down’s Syndrome: a literature review

This article reviews the literature on prenatal screening for Down’s syndrome. To be evidence based, medicine and nursing have to take account of research evidence and also of how this evidence is processed through the influence of prevailing social and moral attitudes. This review of the extensive literature examines how appropriate widely-held understandings of Down’s syndrome are, and asks whether or not practitioners and prospective parents have access to the full range of moral arguments and social evidence on the matter. Highly valued ideals of justice, personal autonomy, parental choice, women’s control over their reproduction and of avoiding harm can all tend towards negative rather than neutral approaches to Down’s syndrome. This article considers how ethics and prenatal screening policies and practice that take greater account of social evidence of disability could use moral arguments that inform rather than determine the choices of people who use prenatal services.

Fetal heart defects: potential and pitfalls of first-trimester detection

Congenital heart defects (CHDs) are the leading cause of infant mortality due to birth defects. In the last 15 years, with the shift in screening for aneuploidies to the first trimester, extensive research has concentrated on early screening and detection of CHDs. Early detailed assessment of the fetal heart requires a high level of expertise in early anomaly scanning and fetal echocardiography. However, the detection of major CHDs at 11-13 weeks is influenced by their association with easily detectable markers, such as the nuchal translucency, ductus venosus blood flow and tricuspid regurgitation, and a policy decision as to the objectives of this scan and the allocation of resources necessary to achieve them. The use of transvaginal ultrasound and newer techniques are likely to improve the detection rate. However, the limitations of fetal echocardiography in the first trimester must be borne in mind, and follow-up at mid-gestational echocardiography is prudent in some cases.

First-trimester detection of structural abnormalities and the role of aneuploidy markers

OBJECTIVES

To determine the sensitivity of first-trimester ultrasound for diagnosing different structural anomalies in chromosomally normal pregnancies, and to establish the role of aneuploidy markers in the detection of abnormalities.

METHODS

This was a retrospective study of chromosomally normal singleton pregnancies with an 11-14-week scan performed in our center during 2002-2009. The ultrasound examination included an early fetal anatomy survey and assessment of nuchal translucency, ductus venosus blood flow and nasal bone.

RESULTS

Among 13 723 scanned first-trimester pregnancies with no genetic anomalies and complete follow-up, 439 fetuses (3.2%) were found to present with structural anomalies (194 with major anomalies and 245 with only minor anomalies). Forty-nine per cent of major structural anomalies were detected during the first-trimester scan, the highest rates corresponding to acrania (17/17), holoprosencephaly (three of three), hypoplastic left heart syndrome (10/10), omphalocele (six of six), megacystis (seven of eight) and hydrops (eight of nine). Higher than expected detection rates were obtained for skeletal (69%) and cardiac (57%) defects, coincidentally showing the highest presence of an increased nuchal translucency or abnormal ductus venosus blood flow (38% and 52%, respectively). The finding of an absent nasal bone did not appear to be associated with structural defects.

CONCLUSION

About half of major structural abnormalities can be diagnosed in the first trimester. Increased nuchal translucency or abnormal ductus venosus blood flow appear to be associated with cardiac and skeletal defects and may facilitate early detection.

Ethical considerations in first-trimester Down syndrome risk assessment

PURPOSE OF REVIEW

First-trimester risk assessment has now become sophisticated and of increasing relevance and applicability to decision-making by pregnant woman about invasive diagnosis. Ethics is an essential dimension of understanding this relevance and applicability. This paper addresses the ethical dimensions of first-trimester risk assessment for trisomy 21.

RECENT FINDINGS

It is now well established in the ethics and law of the informed consent process that physicians are obligated to offer to patients all medically reasonable alternatives for managing the patient's condition. This disclosure should be guided by the reasonable person standard: the physician should provide clinically important information about the patient's condition or diagnosis, the medically reasonable alternatives for managing it, and the clinical benefits and risks of each such alternative.

SUMMARY

On the basis of the ethics of informed consent, we argue that routinely offering first-trimester risk assessment in centers qualified to provide it is ethically obligatory. We describe how pregnant women can be expected to respond to this offer. We then argue that routinely withholding the results of first-trimester risk assessment is ethically unjustified. The ethics of informed consent is an essential dimension of first-trimester risk assessment for trisomy 21.

Factors influencing women's acceptance of prenatal screening tests

OBJECTIVE

To determine the factors influencing a woman's acceptance of the expanded alpha-fetoprotein (AFP) test.

METHODS

A population-based case-control study. All women (age < 35) who declined the expanded AFP test were identified as eligible cases. Controls were randomly selected from all women (age < 35) who accepted the test.

RESULTS

We interviewed 199 cases and 229 controls before 30 weeks of gestation. While 47% of cases reported opposition to abortion as one of their reasons for declining the test (Group A), the remaining 53% of cases had a variety of other reasons for declining (Group B). After controlling for potential confounders, factors significantly associated with declining the test included: skepticism of the usefulness of the test results (odds ratio (OR) = 33.0), influence from family members (OR = 11.4), low educational level (OR = 7.1), willingness to keep a malformed fetus (OR = 6.2), failure to use providers as useful sources of information (OR = 5.0), and misunderstanding of the purpose of the test (OR = 2.0). Polytomous logistic regression revealed that Groups A and B had different determining factors as well as common factors.

CONCLUSION

While many influential factors for participating in prenatal screening remain unmodifiable, some of them may be addressed to improve women's acceptance of prenatal screening tests.

Prenatal screening and counseling in Iran and ethical dilemmas

OBJECTIVE

Prenatal screening has become an increasingly common procedure all over the world. It offers couples useful information relating to the health of their fetus, although it faces us with serious ethical dilemmas as well. This study was conducted to find out the attitudes of Iranian scholars towards prenatal screening and counseling with respect to ethical issues.

METHODS

Two hundred and one physicians, genetic and religious scholars were interviewed with regard to demographics and attitudes towards the ethical dilemmas in prenatal screening and counseling. Interviews were analyzed using the four-principle approach.

RESULTS

Findings showed scholars' attitudes towards: (1) the right of couples to choose prenatal screening, (2) the role of prenatal screening and counseling concerning termination of an affected fetus, (3) screening results and emotional distress in couples, and (4) the impact of prenatal screening and counseling on disability rate.

CONCLUSION

Iranian scholars were willing to consider prenatal screening to help prevent transmission of diseases to the next generation. This goal is attained through the autonomous choice of the couple to participate in prenatal screening and counseling.

Rethinking autonomy in the context of prenatal screening decision-making

OBJECTIVES

Answering the question: Does the offer of prenatal screening impede women in making autonomous choices?

METHODS

Semi-structured interviews with 59 women to whom a prenatal screening test was offered and who were in the process of taking a decision.

RESULTS

Women described the offer as confronting but expressed a positive attitude towards screening and considered the offer as an opportunity for making up their minds about testing. Participants stated that they took decisions freely to follow their individual perspectives. Nevertheless, they preferred to share the responsibility of taking decisions, and its consequences for other family members, with their partner and close persons.

CONCLUSIONS

The active offer of an unsolicited prenatal test need not be considered as an impediment for making an autonomous choice. The moral significance of prenatal testing is inseparably bound with the social context in which it is practiced. Influence from other persons and emotional reactions due to the test offer can be interpreted as supportive for making a choice. In clinical practice, testing should be timely offered in order to give women the opportunity of discussing their views with significant others. Caregivers should care for the emotions experienced by women so as to help them decide according to their values.

Ethics is an essential dimension of first-trimester risk assessment for trisomy 21

We identify the clinical implications of the ethics of informed consent for risk assessment for trisomy 21. Based on the ethics of informed consent, we argue that routinely offering first-trimester risk assessment in centers qualified to provide it is ethically obligatory. We describe how pregnant women can be expected to respond to this offer. We then argue that routinely withholding the results of first-trimester risk assessment is ethically unjustified. The ethics of informed consent is an essential dimension of first-trimester risk assessment for trisomy 21.

Ethical considerations of early (first vs. second trimester) risk assessment disclosure for trisomy 21 and patient choice in screening versus diagnostic testing

We discuss the clinical implications regarding disclosure of risk assessment for trisomy 21 screening results in the first versus second trimester. Based on the ethical principles of respect for autonomy, beneficence, and justice, we argue that routinely offering first trimester risk assessment in centers qualified to provide it is ethically obligatory and routinely withholding the results of first trimester risk assessment is ethically unjustified. As risk for trisomy 21 occurs along a continuum, no pregnant woman is without risk; thus, offering diagnostic testing to all women is ethically justified. Informed consent and personal choice regarding diagnostic testing and termination of pregnancy shape patients' decisions to undergo first trimester risk assessment for trisomy 21. Appropriate counseling is required to allow for individual choice regarding timing of disclosure.

Aneuploidy screening in the first trimester

This article reviews the performance of first trimester screening for chromosomal anomalies using various combinations of ultrasound and maternal serum biochemical modalities. Detection rates in excess of 90% can be routinely achieved for Trisomy 21, Trisomy 13, Trisomy 18 using a combination of fetal nuchal translucency (NT) thickness and maternal serum free ss-hCG and PAPP-A at 11 + 0 to 13 + 6 weeks of gestation.

Detection of malformations in chromosomally normal fetuses by routine ultrasound at 12 or 18 weeks of gestation-a randomised controlled trial in 39,572 pregnancies

OBJECTIVE

To compare the antenatal detection rate of malformations in chromosomally normal fetuses between a strategy of offering one routine ultrasound examination at 12 gestational weeks (gws) and a strategy of offering one routine examination at 18 gws.

DESIGN

Randomised controlled trial.

SETTING

Multicentre trial including eight hospitals.

POPULATION

A total of 39,572 unselected pregnant women.

METHODS

Women were randomised either to one routine ultrasound scan at 12 (12-14) gws including nuchal translucency (NT) measurement or to one routine scan at 18 (15-22) gws. Anomaly screening was performed in both groups following a check-list. A repeat scan was offered in the 12-week scan group if the fetal anatomy could not be adequately seen at 12-14 gws or if NT was >or=3.5 mm in a fetus with normal or unknown chromosomes.

MAIN OUTCOME MEASURES

Antenatal detection rate of malformed fetuses.

RESULTS

The antenatal detection rate of fetuses with a major malformation was 38% (66/176) in the 12-week scan group and 47% (72/152) in the 18-week scan group (P= 0.06). The corresponding figures for detection at <22 gws were 30% (53/176) and 40% (61/152) (P= 0.07). In the 12-week scan group, 69% of fetuses with a lethal anomaly were detected at a scan at 12-14 gws.

CONCLUSIONS

None of the two strategies for prenatal diagnosis is clearly superior to the other. The 12-week strategy has the advantage that most lethal malformations will be detected at <15 gws, enabling earlier pregnancy termination. The 18-week strategy seems to be associated with a slightly higher detection rate of major malformations, although the difference was not statistically significant.

Women's and health professionals' preferences for prenatal testing for Down syndrome in Australia

AIM

To describe and compare women's and health professionals' preferences for prenatal screening tests for Down syndrome.

DESIGN

Cross-sectional questionnaire survey.

PARTICIPANTS AND SETTING

Women (n = 322) attending for a glucose challenge test at 26 weeks gestation and health professionals (266 midwives and 34 obstetricians) at the Royal Women's Hospital, Melbourne, between 13 December 2002 and 30 April 2003.

OUTCOME MEASURES

The relative value participants attach to attributes of Down syndrome screening tests as determined by conjoint analysis and ranking scales.

RESULTS

Women and health professionals shared similar relative values regarding the importance of detection rate of screening tests, according to coefficients from conjoint analysis models. However, health professionals placed higher relative values on timing of prenatal tests and risk associated with the subsequent diagnostic test than did women. Comparison of coefficients suggests that, compared with health professionals, women would wait longer and accept a greater decrease in detection rate for a test if it was safer. Using the more traditional ranking scale, the safest test was ranked first by 56% of women while 47% of health professionals ranked a test with the highest detection rate first. Equal proportions ( approximately 10%) in both groups ranked the earliest test first.

CONCLUSION

There is a general agreement between pregnant women and health professionals regarding the relative importance they attach to different attributes of a test. However, health professionals appeared to favour earlier timing of tests while women placed greater emphasis on safety. Utilising two different measures of preference demonstrated the complexity of decision-making.

Psychosocial Correlates of Pregnant Women's Attitudes Toward Prenatal Maternal Serum Screening and Invasive Diagnostic Testing: Beyond Traditional Risk Status

This study examined whether psychosocial variables predict pregnant women's attitudes toward maternal serum screening and invasive diagnostic testing, beyond the influence of traditional obstetric risk status (based on advanced maternal age, history of genetic disorders, etc.). In a sample of 612 pregnant women (66.5% high risk, 33.5% low risk) we assessed responses to hypothetical scenarios of invasive testing following normal or abnormal maternal serum screening. We also assessed psychosocial variables stemming from the theory of planned behavior (e.g., knowledge, concern for fetus, attitudes toward termination, health locus of control). Overall, two thirds of the women would want serum screening. Follow-up invasive diagnostic testing would be sought by 37.2% of the women after a negative screening, and by 75.0% after a positive screening. As expected, traditional risk status predicted desire for screening and also invasive testing following either a negative or positive screen. Yet, controlling for risk status, many psychosocial variables predicted a women's interest in screening and in invasive testing: more knowledge about prenatal testing, concern about fetal health, willingness to terminate a pregnancy, and an internal or medical profession health locus of control. We conclude that psychosocial variables influence women's desire for screening or invasive testing beyond traditional risk status.

A comparison of Australian and UK obstetricians' and midwives' preferences for screening tests for Down syndrome

OBJECTIVE

To establish and compare obstetricians' and midwives' preferences for hypothetical prenatal screening tests for Down syndrome.

METHODS

A cross-sectional questionnaire survey was completed by 296 obstetricians and midwives at two teaching hospitals: one in Melbourne, Australia (n = 175), and one in London, UK (n = 94). Conjoint analysis was undertaken using random effects probit regression.

RESULTS

No significant differences were seen in any measurements when comparing obstetricians in Australia and the UK or midwives in Australia and the UK. Obstetricians and midwives shared similar relative values regarding the importance of the detection rate of the screening tests. However, obstetricians placed higher relative values on both timing of prenatal tests and risk associated with the subsequent diagnostic test than did midwives when considering optimal tests to offer women. Marginal rates of substitution suggest that, compared with midwives, obstetricians would wait longer and accept a greater decrease in detection rate for a test if it was safer. Younger midwives placed higher value on both detection rate and safety of prenatal tests than older midwives. Female obstetricians placed higher value on the timing of a test than male obstetricians.

CONCLUSION

Obstetricians in Australia and UK placed almost identical importance on test attributes, as did the midwives in the two countries. However, different attitudes towards tests were seen between obstetricians and midwives.

Comparing Three Screening Strategies for Combining First- and Second-Trimester Down Syndrome Markers

OBJECTIVE

To describe the choices and tradeoffs inherent in 3 published strategies that combine first- and second-trimester markers for Down syndrome screening.

METHODS

Published marker distributions for Down syndrome and unaffected pregnancies in the first and second trimesters were combined with a maternal age distribution and age-associated Down syndrome risk in a statistical model to compare sequential, contingent, and integrated screening.

RESULTS

Sequential and contingent screening strategies are always less efficient (higher false-positive rate for a given detection rate) than integrated screening, but the reduction in efficiency is dependent on the combination of risk cutoffs chosen. At a fixed false-positive rate, sequential and contingent strategies perform better when a higher proportion of the false positives occur in the second trimester. For all 3 strategies, increasing the overall false-positive rate from 2% to 5% increases detection (from approximately 85% to 91%). Although associated with reduced screening efficiency compared with integrated screening, both sequential and contingent screening identify the majority of detected Down syndrome cases early. With contingent screening, the process is also completed in the first trimester for most women.

CONCLUSION

Integrated screening is the most efficient of the 3 strategies, but it is possible to select risk cutoffs for both sequential and contingent strategies that minimize losses in efficiency while maintaining early detection and early completion. For all of these strategies, well-designed intervention trials are needed to determine acceptability to women and providers in primary care settings and to assess real-world performance.

LEVEL OF EVIDENCE

III.

Women's opinions on the offer and use of nuchal translucency screening for Down syndrome

OBJECTIVE

To study the attitude of Dutch women to the offer and subsequent (non)use of nuchal translucency (NT) screening for Down syndrome in the first trimester of pregnancy, in a country where screening is not routinely offered under 36 years of age.

METHODS

An experimental NT screening programme offered to pregnant women, together with a series of questionnaires to be completed before and after the offer and (non)use of screening, in 12 midwife practices in three different health districts.

PARTICIPANTS

Cohort of pregnant women who had their first prenatal care visit in the participating midwife practices between 1 June 1999 and 1 January 2001.

MAIN OUTCOME MEASURES

Women's knowledge and understanding of prenatal screening tests; attitude towards screening offer; perceived freedom of choice; satisfaction with information given; change in attitude over time.

RESULTS

Eighty-six percent of women accepted the offer of NT screening. Seventy percent had previous knowledge of NT screening and 92% considered the information given before screening clear and sufficient. Thirty-nine percent of women felt worried to some extent after being given the information, but only 3% would have preferred not to have been informed at all. Ninety percent of women (including 68% of decliners) agree that information on Down syndrome screening should be extended to all pregnant women and feel competent in deciding on screening participation.

CONCLUSION

When NT screening is offered as a new screening strategy its concept is understood and well accepted. The large majority of women, including the decliners, are in favour of its standard offer.

Patient preference regarding first-trimester aneuploidy risk assessment

OBJECTIVE

We assessed patient views regarding disclosure of first-trimester Down syndrome risk assessment results compared with withholding results until a single, more accurate second-trimester screening result is available.

STUDY DESIGN

A prospective, institutional review board-approved, voluntary, anonymous survey was presented to patients with singleton pregnancies who were undergoing first-trimester nuchal translucency and biochemical screening at our institution. Options included immediate (sequential testing) or later disclosure (integrated testing). Descriptions and a comparison of the options were included in the survey.

RESULTS

One hundred one women completed the questionnaires; 69.3% of the patients preferred sequential testing, compared with 30.7% of the patients who were either unsure or preferred integrated testing. Older patients and those patients with better background knowledge of screening tests preferred earlier disclosure of screening results (P = .035 and P = .026, respectively). Patients who preferred earlier disclosure also preferred termination of a Down syndrome pregnancy (P = .013).

CONCLUSION

Older patients and those patients with a better understanding of screening tests preferred immediate disclosure of first-trimester risk assessment results; these women were more likely to prefer to terminate an affected pregnancy.

Patient and health professional acceptance of integrated serum screening for Down syndrome

Integrated testing for Down syndrome combines first trimester maternal serum and nuchal translucency (NT) measurements with second trimester maternal serum measurements into a single second trimester Down syndrome risk. A variant of integrated testing, the integrated serum test, requires only the serum measurements and may be more suitable for widespread use in the general pregnancy population. Concern has been voiced that women will find the delay associated with waiting for screening results unacceptable for either fully integrated (including NT measurements) or integrated serum testing. To address this issue, we surveyed 60 women from a population of 8773 women enrolled in an integrated serum screening intervention trial in Maine. The women all had also undergone traditional second trimester screening 1 to 2 years earlier. All 60 women remembered having the integrated serum test, and 59 remembered having a prenatal test in their previous pregnancy. Three-quarters of women did not experience anxiety relating to the wait for final results in the second trimester, and 95% would consider being screened by the integrated serum test in a future pregnancy. Women receiving prenatal care at the primary care level are prepared to wait until the second trimester for more accurate Down syndrome risk estimates on which to base their decision-making.

Clinical implications of the ethics of informed consent for first-trimester risk assessment for trisomy 21

OBJECTIVE

We identify the clinical implications of the ethics of informed consent for risk assessment for trisomy 21.

FINDING

Based on the ethics of informed consent, we find that routinely offering first-trimester risk assessment in centers qualified to provide it is ethically obligatory, and routinely withholding the results of first-trimester risk assessment is ethically unjustified.

CONCLUSION

The ethics of informed consent is an essential dimension of first-trimester risk assessment for trisomy 21.

Implementation of first-trimester risk assessment for trisomy 21: ethical considerations

The performance and evaluation of first-trimester risk assessment should meet standards of scientific and ethical excellence. Scientific standards are well understood. Ethical standards are less well understood. On the basis of the ethical concept of the physician as fiduciary, and the ethical principles of respect for autonomy, beneficence, and justice, we show that the obstetrician has an ethical obligation to routinely offer pregnant women first-trimester risk assessment in high quality centers. On the basis of the professional virtues of integrity and self-sacrifice, we then show that both obstetricians and specialists in risk assessment have a strict ethical obligation to identify, responsibly manage, and disclose both economic and noneconomic conflicts of interests, especially when they are hidden. We conclude that ethics is an essential dimension of implementation of first-trimester risk assessment for trisomy 21.

Screening for Down syndrome based on maternal age or fetal nuchal translucency: a randomized controlled trial in 39,572 pregnancies

OBJECTIVES

Nuchal translucency (NT) screening increases antenatal detection of Down syndrome (DS) compared to maternal age-based screening. We wanted to determine if a change in policy for prenatal diagnosis would result in fewer babies born with DS.

METHODS

A total of 39,572 pregnant women were randomized to a scan at 12-14 gestational weeks including NT screening for DS (12-week group) or to a scan at 15-20 weeks with screening for DS based on maternal age (18-week group). Fetal karyotyping was offered if risk according to NT was > or = 1:250 in the 12-week group and if maternal age was > or = 35 years in the 18-week group. Both policies included the offer of karyotyping in cases of fetal anomaly detected at any scan during pregnancy or when there was a history of fetal chromosomal anomaly. The number of babies born with DS and the number of invasive tests for fetal karyotyping were compared.

RESULTS

Ten babies with DS were born alive with the 12-week policy vs. 16 with the 18-week policy (P = 0.25). More fetuses with DS were spontaneously lost or terminated in the 12-week group (45/19,796) than in the 18-week group (27/19 776; P = 0.04). All women except one with an antenatal diagnosis of DS at < 22 weeks terminated the pregnancy. For each case of DS detected at < 22 weeks in a living fetus there were 16 invasive tests in the 12-week group vs. 89 in the 18-week group. NT screening detected 71% of cases of DS for a 3.5% test-positive rate whereas maternal age had the potential of detecting 58% for a test-positive rate of 18%.

CONCLUSIONS

The number of newborns with DS differed less than expected between pregnancies that had been screened at 12-14 weeks' gestation by NT compared with those screened at 15-20 weeks by maternal age. One explanation could be that NT screening--because it is performed early in pregnancy--results in the detection and termination of many pregnancies with a fetus with DS that would have resulted in miscarriage without intervention, and also by many cases of DS being detected because of a fetal anomaly seen on an 18-week scan. The major advantage of the 12-week scan policy is that many fewer invasive tests for fetal karyotyping are needed per antenatally detected case of DS.

Accepting or declining the offer of prenatal screening for congenital defects: test uptake and women's reasons

OBJECTIVES

Prenatal screening for Down syndrome has become standard practice in many western countries. In the Netherlands, however, prenatal screening tests for congenital defects are not offered routinely. The present study aims to assess test uptake in a large, unselected population of pregnant women, and to give more insight into the decision for or against prenatal screening through nuchal translucency measurement or maternal serum screening.

PATIENTS AND METHODS

The study is part of a randomized controlled trial with two groups, each being offered a different prenatal screening test, and a control group. Pregnant women received postal questionnaires at three stages of their pregnancy.

RESULTS

Of the women being offered the nuchal translucency measurement or the second trimester maternal serum test, 53 and 38% respectively accepted the test offer. The main reasons for accepting were 'gaining knowledge about the health of the foetus/curiosity' (50%), 'favourable characteristics of the screening test' (18%), and 'increased risk of having a child with DS' (15%). The main reasons for declining were 'unfavourable characteristics of the screening test' (42%), 'not applicable/not necessary' (35%), 'anxiety/uncertainty' (36%), 'adverse characteristics of the invasive tests' (32%), and 'being against abortion' (15%).

DISCUSSION

The uptake of prenatal screening was relatively low, and different distributions of reasons were reported, compared to other studies. These differences may be due to the specific Dutch situation in which prenatal screening is not part of standard prenatal care. The question arises as to whether informed decision-making would be reduced if prenatal screening became routinised.

Factors affecting women's preference for type of prenatal screening test for chromosomal anomalies

OBJECTIVE

To ascertain, by means of a questionnaire, women's preferences for four different approaches to prenatal screening for Down syndrome.

METHODS

Women attending antenatal clinics at six UK maternity units were asked to put in order of preference four different approaches to screening for Down syndrome all of which had the same false positive rate of 5%. The options were: (1) first-trimester testing, 90% detection of Down syndrome with results available in 1 h at one-stop clinics for the assessment of risk (OSCAR); (2) first-trimester testing, 90% detection and results available within 2-3 days (combined screening); (3) first-trimester testing plus second-trimester testing, 93% detection and results available within 2-3 days of second test (integrated testing); (4) second-trimester testing, 75% detection and results available within 2-3 days.

RESULTS

Over 1100 women attending antenatal clinics at six maternity units across the UK returned the questionnaire. A total of 75% of women selected a first-trimester test (option 1 or option 2) as their first choice with 68.2% expressing a preference for the OSCAR approach and a further 6.8% for combined screening. Twenty-four percent of women opted for integrated testing as their first choice with only 1% expressing a preference for second-trimester screening.

CONCLUSIONS

A first-trimester test is preferred by the majority of women over a test with marginally higher detection rate that delivers results later in pregnancy. Timing and rapid reporting of results appear to influence women's choice of test.

People who influence women's decisions and preferred sources of information about prenatal testing for birth defects

BACKGROUND

More than half of Victorian pregnant women are undergoing prenatal testing for birth defects, although little is known about the factors that are influencing their decisions.

AIMS

To examine whom women perceived as influencing their decision about prenatal testing for birth defects, with whom they would have liked to talk more, and what sources of information they preferred.

METHODS

A total of 737 pregnant women aged 37 years and over, who either had or had not undergone prenatal testing (screening and/or diagnosis) completed a questionnaire in 18 hospitals throughout Victoria.

RESULTS

Over 90% reported that they themselves had a strong influence on their decision, and 70% reported their partner as strongly influencing their decision. Approximately 30% of women who had both screening and diagnosis and more than 20% of women who had no prenatal testing, would like to have discussed prenatal testing with women who had previously had testing. Face-to-face counselling with a doctor or counsellor was the preferred source of information, followed by a pamphlet as the second choice.

CONCLUSIONS

Given that both tested and untested women felt so strongly that they were responsible for their own decisions about prenatal testing, it is unlikely that universal acceptance and uptake will occur, even in this group of women of advanced maternal age. A support network of women who have already had testing could supplement existing sources of support. However, there continues to be a need for face-to-face sessions with a doctor or counsellor in combination with printed material.

Women and health care professionals' preferences for Down's Syndrome screening tests: a conjoint analysis study

OBJECTIVE

To describe and compare women and health care professionals' preferences for Down's Syndrome screening tests with different test characteristics.

DESIGN

Cross sectional questionnaire based conjoint analysis study.

SETTING

London teaching hospital.

SAMPLE

291/383 women in their first or second trimester of pregnancy and 98/122 health care professionals (41 obstetricians, senior house officers and above and 57 qualified midwives) providing care at the same hospital.

METHODS

Women completed a questionnaire while attending a clinic visit for a dating scan or a routine 20-week anomaly scan. Health care professionals completed a postal questionnaire.

MAIN OUTCOME MEASURES

The relative values participants attach to Down's Syndrome screening test attributes: time of test, detection rate and risk of miscarriage of a baby unaffected by Down's Syndrome as a result of subsequent diagnostic tests.

RESULTS

Pregnant women and health care professionals shared broadly similar relative values regarding the importance of safe tests, conducted early and with high detection rates. When asked to choose between different Down's Syndrome screening tests, health care professionals valued earlier tests more highly than did women.

CONCLUSIONS

While pregnant women and health care professionals share similar relative values regarding optimal prenatal tests, health care professionals place a higher value on earlier tests. This may result in screening policies that overweight timing in the selection of a test to the relative neglect of tests associated with lower miscarriage rates and higher detection rates but conducted later in pregnancy.

Psychological responses to prenatal NTS counseling and the uptake of invasive testing in women of advanced maternal age

This study examines women's psychological responses to prenatal group genetic counseling, and to subsequent individualized risk counseling. All women (N=123) aged 35 and older underwent nuchal translucency screening (NTS), a prenatal ultrasound screening test. After group counseling, decisional conflict decreased significantly among those reporting at baseline having made a decision about invasive testing (t(222)=2.0, P=0.014) and for those who were uncertain (t(222)=5.74, P <0.0005). After receiving NT-adjusted risks, decisional conflict decreased further for those uncertain about testing at baseline (t(222)=4.64, P <0.0005). There was no change in risk perception and anxiety after group counseling. After NT-adjusted risks were communicated, risk perception decreased significantly (t(230)=5.02, P <0.0005), as did anxiety (t(115)=7.91, P <0.005). Despite reassuring NTS results, the uptake rate for prenatal invasive testing was 78.4%. Risk perception, anxiety, and decisional conflict decreased after individual counseling for reassuring NTS results, but the uptake of invasive testing remained high.

Prospective evaluation of a first trimester screening program for Down syndrome and other chromosomal abnormalities using maternal age, nuchal translucency and biochemistry in an Australian population

BACKGROUND

A combination of maternal age and ultrasound assessment of the nuchal translucency (NT) has been used in the first trimester to screen for chromosomal abnormality. In the United Kingdom, the addition of NT screening was shown to be beneficial.

AIMS

To report the sensitivity of combined first trimester biochemistry and ultrasound screening for Down syndrome in an Australian private practice specialising in obstetric ultrasound.

METHODS

A prospective study in a private obstetric ultrasound practice. Over 22 months, 2121 patients were screened and data was analysed for sensitivity (detection) and false positive rates for all chromosome abnormalities.

RESULTS

There were 17 chromosomal abnormalities, five of which were Down syndrome. Using maternal age alone or age and biochemistry, four of the Down syndrome cases were detected for a 29 and 19% false positive rate, respectively. Using age and NT or age, NT and biochemistry, all the Down syndrome cases were detected, for a false positive rate of 5.7 and 7.2%, respectively. The difference in detection rates for Down syndrome or other chromosomal abnormalities, using the four screening methods, did not reach statistical significance. However, the false positive rates in screening methods without ultrasound to assess the NT was significantly higher (P < 0.01).

CONCLUSIONS

A combination of maternal age, NT and maternal serum biochemistry gives a high detection rate for both trisomy 21 and other chromosomal abnormalities. Down syndrome screening using either maternal age alone or age in combination with first trimester biochemistry conferred screen positive rates significantly higher than when combined with NT.

Is nuchal translucency screening associated with different rates of invasive testing in an older obstetric population?

OBJECTIVE

Our objective was to assess the impact of nuchal translucency screening for aneuploidy on chorionic villus sampling and amniocentesis rates in an older obstetric population.

METHODS

Our study population included women >/=35 years old who were delivered at our hospital from January 1, 2000 through December 31, 2002. Records were reviewed to determine whether women underwent nuchal translucency, chorionic villus sampling, and amniocentesis. The chi-squared test for trend was used to evaluate changes in nuchal translucency, chorionic villus sampling, and amniocentesis rates over six 6-month intervals. Maternal characteristics were compared with the use of Mann-Whitney U test and Fisher's exact test.

RESULTS

The 4029 women who met the inclusion criteria had a median age at delivery of 37 years (interquartile range, 36-39 years). The rates of nuchal translucency screening increased from 0% to 41.6% over the study interval. Women who underwent nuchal translucency screening when it was available were older than the women who did not (median age, 37 years [interquartile range, 36-40 years] vs median age, 37 years [interquartile range, 36-39 years]; P=.003). A higher proportion of women who were >/=40 years old underwent nuchal translucency screening when it was available than did women who were 35 to 39 years old (24.9% vs 20.4%; P=.01). Women who underwent nuchal translucency screening were less likely to have chorionic villus sampling compared with women who did not undergo screening (1.9% vs 7.1%; P<.001). Rates of chorionic villus sampling declined over time, although amniocentesis rates remained unchanged. The overall rate of invasive testing declined. Different trends were noted in women who were 35 to 39 years old compared with women who were >/=40 years old.

CONCLUSION

Higher rates of nuchal translucency screening were associated with lower rates of chorionic villus sampling and invasive testing. The addition of first-trimester screening may lead to reduced rates of invasive testing and fewer losses of normal pregnancies.

Invasive procedures in multiple gestations

PURPOSE OF REVIEW

The incidence of multiple gestations has increased significantly with advances in assisted reproductive techniques resulting in a concomitant increase in invasive procedures in these pregnancies. Commonly performed invasive procedures include amniocentesis, chorionic villus sampling, multifetal pregnancy reduction, and selective termination. Amniocentesis and chorionic villus sampling are also performed in singleton pregnancies, while multifetal pregnancy reduction and selective termination are procedures that are unique to multiple gestations.

RECENT FINDINGS

With increased operator experience, pregnancy loss rates after chorionic villus sampling, multifetal pregnancy reduction, and selective termination have decreased to acceptably low levels. Amniocentesis and chorionic villus sampling continue to have similar loss rates in experienced hands. A recent study suggests that amniocentesis in twins may have a higher post-procedural loss rate than in singletons; this may be due to the higher background loss rate of twins. There has been a recent increase in multifetal pregnancy reduction to a singleton with a trend towards improved outcomes over reduction to twins; future studies should focus on whether this confers a definitive advantage. Newer data suggests that selective termination after 20 weeks gestation in experienced hands does not increase loss rates over those procedures performed before 20 weeks. Newer techniques, such as cord coagulation, continue to be developed for selective termination in monochorionic pregnancies, though still with considerable morbidity and mortality.

SUMMARY

In summary, invasive procedures in multiple gestations are now commonly performed with. It is our hope that primary prevention of high order multiple pregnancies by optimization of assisted reproductive techniques will decrease the need for these procedures.

Combined first-trimester versus second-trimester serum screening for Down syndrome: a cost analysis

OBJECTIVE

The purpose of this study was to compare the cost-effectiveness of combined first-trimester screening for fetal Down syndrome with second-trimester maternal serum triple screening.

STUDY DESIGN

A first-trimester screening approach that used nuchal translucency measurement and maternal serum screening was evaluated against second-trimester maternal serum triple screening in a hypothetic population. Screening sensitivities and screen-positive rates were 91% and 5% for the first-trimester approach and 70% and 7.5% for the second-trimester approach, respectively. The costs of fetal Down syndrome, live-born Down syndrome cost, and total costs (screening plus live-born costs) were calculated for each screening program.

RESULTS

First-trimester screening was associated with lower screening and live-born Down syndrome costs versus second-trimester serum screening. Total Down syndrome screening costs were 29.1% lower with first-trimester screening.

CONCLUSION

In this hypothetic model, combined first-trimester screening for fetal Down syndrome was more cost-effective than universal second-trimester triple serum screening.

Women's preferences for reporting of Down syndrome screening results

OBJECTIVE

The aim of this study was to determine whether women prefer the results of screening for Down syndrome tests to be reported as the risk of Down syndrome in early pregnancy at the time of the screening test or the risk at delivery (which takes into account the number of Down syndrome pregnancies that will be spontaneously lost before birth).

DESIGN

A structured questionnaire.

SETTING

A tertiary hospital antenatal clinic.

SAMPLE

One hundred and fifteen English-speaking women who expressed an interest in having screening tests for Down syndrome performed.

METHODS

A structured questionnaire exploring women's preferences for risk reporting was self administered by women attending for their first antenatal visit.

MAIN OUTCOME MEASURES

Women's preference for reporting of screening test results as risk at time of test, risk at birth or both, and the reasons for this preference.

RESULTS

The majority (n = 82) of women preferred to have both the risk of Down syndrome at the time of screening and at the time of birth reported. The most common reason (n = 60) given for this preference was a desire to have as much information available as possible so that an informed decision regarding further investigations could be made.

CONCLUSIONS

The majority of women prefer to receive Down syndrome screening results as both the risk at the time of the test and the risk at birth.

Womens' preference in Down syndrome screening

OBJECTIVE

To determine the knowledge of pregnant women about prenatal tests, and what tests they would choose if offered. Also, the preference of pregnant women for second-trimester or first-trimester screening was assessed.

PATIENTS AND METHODS

Pregnant women receiving antenatal care in a decentralized primary care system (n=80), and pregnant women that were offered a prenatal diagnosis at the Academic Medical Centre (n=195), were asked to complete a questionnaire.

RESULTS

The response rate was over 80%. Most women in both groups preferred a screening test for Down syndrome to be performed in the first trimester of pregnancy. A combination of nuchal translucency measurement and first-trimester serum screening was the option of choice. The screening possibilities for Down syndrome were less well known to the women in the low-risk group compared with the women in the high-risk group. The offer of a prenatal screening test would have been declined by more than 30% of women at low risk for carrying a fetus with Down syndrome.

CONCLUSIONS

Our results show that women prefer screening for Down syndrome to be performed in the first trimester of pregnancy, using both serum and ultrasound tests. In women at low risk for Down syndrome the knowledge of prenatal screening methods was less, as well as the acceptance of prenatal screening being lower.

Predictive value of hormone measurements in maternal and fetal complications of pregnancy

Intrauterine tissues (placenta, amnion, chorion, decidua) express hormones and cytokines that play a decisive role in maternal-fetal physiological interactions. The excessive or deficient release of some placental hormones in association with gestational diseases may reflect an abnormal differentiation of the placenta, an impaired fetal metabolism, or an adaptive response of the feto-placental unit to adverse conditions. This review is focused on the applicability of hormone measurements in the risk assessment, early diagnosis, and management of pregnancies complicated by Down's syndrome, fetal growth restriction, preeclampsia, preterm delivery, and diabetes mellitus. Combined hormonal tests or the combination of hormones and ultrasound may achieve reasonable sensitivity, but research continues to simplify the screening programs without sacrificing their accuracy. Only in a few instances is there sufficient evidence to firmly recommend the routine use of hormone tests to predict maternal and fetal complications, but the judicious use of selected tests may enhance the sensitivity of the risk assessment based solely on clinical and ultrasound examination.

Favorable attitudes toward testing for chromosomal abnormalities via analysis of fetal cells in maternal blood

PURPOSE

The NICHD Fetal Cell Isolation Study (NIFTY) was a multicentered project to isolate fetal cells from maternal blood to detect fetal chromosomal abnormalities. The project included a psychosocial component, which is the basis of this article. We examined the attitudes of high-risk pregnant women toward the availability of a maternal blood test to identify fetal chromosomal abnormalities, how women would respond to hypothetical normal and abnormal maternal blood testing results, and the factors associated with a woman's preference to have an invasive procedure in response to a normal maternal blood test.

METHODS

High-risk pregnant women (N = 854) planning to have prenatal diagnostic invasive testing (amniocentesis or chorionic villus sampling) completed a survey.

RESULTS

The women highly favored maternal blood testing. Almost all women would seek invasive testing after an abnormal blood test. Only half of the women would seek invasive testing after a normal blood test; these women were older, more willing to terminate their pregnancy, and valued the increased accuracy of invasive testing more highly than women who would not have invasive testing after a normal maternal blood test.

CONCLUSIONS

Women having invasive diagnostic testing welcome a noninvasive procedure that uses fetal cells in maternal blood, and its availability would decrease invasive testing by approximately 50%. Research needs to examine the attitudes and anticipated responses of other risk groups as well as the effects of information about maternal blood test sensitivity and specificity on attitudes and responses.

Outcome of first-trimester chorionic villus sampling for genetic investigation in multiple pregnancy

OBJECTIVES

To evaluate the efficacy of and risk associated with chorionic villus sampling for genetic investigations in multiple pregnancies, and to evaluate the accuracy of the ultrasonographic detection of chorionicity during the first trimester.

PATIENTS AND METHODS

A total of 198 sets of twins and nine sets of triplets from 10 087 consecutive first-trimester pregnancies undergoing chorionic villus sampling were considered. Gestational age ranged from 7 to 12.6 weeks. Assessment and confirmation of chorionicity was based on a multiplicity of features. Dichorionicity was established in 169 sets of twins (85.3%) and trichorionicity in all triplet cases, while 29 twins were considered monochorionic. Chorionic villus sampling was performed transabdominally in all but one case, and identification of the placental insertion of the umbilical cord was the main benchmark for sampling. Sampling risks were evaluated by comparing clinical outcome with that of a control population of 63 dichorionic twin pregnancies which underwent no invasive procedure.

RESULTS

Determination of the presence or absence of the lambda sign led to a correct assignment of chorionicity in all cases, while the presence of a membrane thickness of 2 mm or more reflected a 100% specificity with a 22% false negative rate. Sampling was successfully performed in all cases and in only four cases (1.0%) were two needle insertions needed. At follow-up no evidence of incorrect sampling was reported. Karyotyping was provided to all patients, and in 94.1% of cases both short and long-term culture methods were carried out. No difference in fetal and perinatal losses between the study and control populations was found, but a higher rate of deliveries before 37 weeks and of low birth weight babies was noted amongst controls.

CONCLUSIONS

Chorionicity in twin pregnancy can be determined with certainty between 7 and 12 weeks of gestation; in cases of confluent placentas reliability is provided by determining the presence or absence of the lambda sign. This study indicates that first-trimester transabdominal chorionic villus sampling is a highly efficient, reliable, and relatively safe approach for genetic diagnosis in twin pregnancies. Although a precise evaluation of the relative risks of chorionic villus sampling and mid-trimester amniocentesis in twins must await randomized control studies, the advantages of a first-trimester diagnosis to enable early decision-making about selective fetal reduction are obvious.

Women's knowledge of and attitudes to first and second trimester screening for Down's syndrome

One hundred women were interviewed at their first hospital antenatal visit to assess their knowledge of, and attitudes to, first versus second trimester screening for Down's syndrome. Overall, the women had limited knowledge of Down's syndrome, and the prenatal screening and diagnostic tests that are available. However, when informed, the majority of women expressed a clear preference for first trimester screening tests for Down's syndrome, regardless of the rate of miscarriage of Down's syndrome pregnancies between 10 and 15 weeks of gestation. These findings have implications for the planning of prenatal Down's syndrome screening programmes.

How women deal with the results of serum screening for Down syndrome in the second trimester of pregnancy

To gain insight into how pregnant women experience serum screening for Down syndrome, we sent questionnaires to two groups of relevant subjects in the north of the Netherlands. The questionnaires addressed the following issues: decision-making process, knowledge and opinions. Questionnaire A was sent to women of 36 years of age and older (n=99) (group A) who were all 20 to 36 weeks pregnant at that time. In the Netherlands prenatal diagnosis is routinely available to these women. Questionnaire B was sent to women of younger than 36 years (n=69) (group B) who had received a screen-positive result and had subsequently undergone amniocentesis. About half of these women were still pregnant at that time. For these women, serum screening is only available on the basis of opting-in. The two questionnaires were largely identical. The response rates to questionnaires A and B were 82% and 91%, respectively. Group A (women of 36 years and older) considered that second trimester serum screening made a welcome contribution to the decision-making process about whether to undergo amniocentesis. Moreover, it reduced the amniocentesis rate considerably. The vast majority said they would apply for serum screening in a following pregnancy, but favoured the idea of first trimester screening. In group B (women of younger than 36 years), reassurance was the most commonly mentioned reason for undergoing serum screening. Almost all the women experienced some degree of anxiety when they were informed about the screen-positive result and 13% continued to be anxious, even after the favourable result of the amniocentesis. The majority of the respondents would also apply for serum screening in a following pregnancy and were of the opinion that this screening should be offered to all pregnant women in the Netherlands.

Uptake of Down syndrome screening in an Australian Vietnamese population

It has been previously shown that the uptake of prenatal diagnosis by Victorian women of a non-English speaking background is significantly lower than that of comparable English speaking women. To explore this further we have examined the uptake of Down syndrome screening and diagnosis by Vietnamese women attending a community-based antenatal clinic in metropolitan Melbourne over a two year period. Of the 207 women studied, 161 (78%) were offered screening or diagnosis and of these women 139 (86%, 95%CI 81-92%) accepted the offer, representing 67% (95%CI 61-74%) of the entire population. Of the 127 women who had screening, rather than diagnosis, 12 (9%) had an 'increased risk' result. Eleven of these women accepted diagnosis. We also explored the reasons why 45 (22%) of women were not offered screening. Almost half (44%) of these women first attended the clinic at a too advanced stage of gestation but in 25 women there were no obvious reasons. These results are discussed in the context of current prenatal screening and diagnostic practice in Victoria and simple recommendations made.

First trimester screening for aneuploidy: serum biochemical markers

The article reviews screening for Down syndrome in the first trimester (8-13 gestational weeks) with maternal serum analytes. In the first trimester, 2 serum markers stand out: pregnancy-associated plasma protein-A, a large glycoprotein tetramer, and free beta-human chorionic gonadotropin (beta-hCG), 1 of the 2 subunits of the glycoprotein hormone hCG. Some data indicate that hCG itself may be as effective as free beta-hCG in the first trimester. Maternal serum levels of pregnancy-associated plasma protein-A are low and free beta-hCG are high (consensus multiple of the medians, 0.4 and 1.8, respectively) in Down syndrome pregnancy. The consensus estimate of screening performance by using pregnancy-associated plasma protein-A and free beta-hCG in combination with maternal age is 60% detection rate at a 5% false positive rate. This is similar to the screening performance of second trimester double markers, but not as good as the screening performance of second trimester triple or quad markers. For this reason, first trimester screening with serum markers alone cannot be recommended except in cases in which second trimester screening cannot be done.