The extent of Down's syndrome screening in Britain in 1991

Latinas, amniocentesis and the discourse of choice

Little attention has been paid to the impact of the increasingly routine use of fetal diagnosis on how U.S. minority women experience their pregnancies and decide whether to have their fetuses tested. Using narrative analysis, we offer the account of one Latina who, despite considerable turmoil, ultimately accepted an offer of amniocentesis. We describe her reasoning in choosing a course of action. Data from interviews with 147 Latinas who were faced with the same decision are used to contextualize the case study material. We seek to illuminate how a blending of Mexican and European American cultural influences helped shape the woman's experience and define the dilemma she faced when she learned her fetus might be born with a grave or incurable condition because she was ideologically opposed to abortion.

Down's syndrome screening in the UK in 1998

The extent of antenatal screening for Down's syndrome with serum or ultrasound markers has increased over the past decade. We here present a survey of screening in the UK in 1998 and compare the results with similar surveys from 1991 and 1994.

Second-trimester maternal serum inhibin-A screening for fetal Down syndrome in Asian women

Case control studies in the Caucasian population showed that maternal serum inhibin-A is elevated in Down syndrome pregnancies and may be a useful second-trimester marker in addition to human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP). Data in the Asian population are lacking. We measured inhibin-A levels in the stored maternal sera of 49 Down syndrome pregnancies and 341 controls with a commercially available assay and expressed them as the multiples of the median of the gestational week. The log means and standard deviations for case and control inhibin-A MOMs were 0.209, 0.226, and 0.002 and 0.177, respectively. Median inhibin-A MOM in Down syndrome cases was elevated to 1.62 (95 per cent confidence interval, 1.29-1.82). 36 per cent of Down syndrome cases were expected to be detected at a 5 per cent false-positive rate. However, inhibin-A MOMs were strongly correlated with hCG MOMs in the cases (r=0.73, p<0.001) and the controls (r=0.56, p<0.001). This will diminish the value of adding inhibin-A to the existing hCG and AFP screening protocol.

Variation in biochemical screening for Down's syndrome in the United Kingdom

A questionnaire survey was undertaken of all 73 laboratories performing Down's syndrome screening in 1995. An estimated 352,000 tests were performed representing 47% of maternities. Three-quarters of these tests have ultrasound dating information at the time of testing. The majority of laboratories (70%) commenced screening at 15 weeks of gestation or later, and there was considerable variation in the upper limit of screening (17 to 24 weeks). Eighty-six percent of laboratories screened all women regardless of age. The reported Down's syndrome risk was based on term in 85% of laboratories. There was an inconsistent approach to determining and reporting high risk for trisomy 18 (Edwards' syndrome): 5% reported risks on report forms and 42% notified the clinicians if the risk was considered to be raised.

Antenatal screening for Down's syndrome

BACKGROUND

In 1968 the first antenatal diagnosis of Down's syndrome was made and screening on the basis of selecting women of advanced maternal age for amniocentesis was gradually introduced into medical practice. In 1983 it was shown that low maternal serum alpha fetoprotein (AFP) was associated with Down's syndrome. Later, raised maternal serum human chorionic gonadotrophin (hCG), and low unconjugated oestriol (uE3) were found to be markers of Down's syndrome. In 1988 the three biochemical markers were used together with maternal age as a method of screening, and this has been widely adopted. PRINCIPLES OF ANTENATAL SCREENING FOR DOWN'S SYNDROME: Methods of screening need to be fully evaluated before being introduced into routine clinical practice. This included choosing markers for which there is sufficient scientific evidence of efficacy, quantifying performance in terms of detection and false positive rates, and establishing methods of monitoring performance. Screening needs to be provided as an integrated service, coordinating and managing the separate aspects of the screening process. SERUM MARKERS AT 15-22 WEEKS OF PREGNANCY: A large number of serum markers have been found to be associated with Down's syndrome between 15 and 22 weeks of pregnancy. The principal markers are AFP, hCG or its individual subunits (free alpha- and free beta-hCG), uE3, and inhibin A. Screening performance varies according to the choice of markers used and whether ultrasound is used to estimate gestational age (table 1). When an ultrasound scan is used to estimate gestational age the detection rate for a 5% false positive rate is estimated to be 59% using the double test (AFP and hCG), 69% using the triple test (AFP, hCG, uE3), and 76% using the quadruple test (AFP, hCG, uE3, inhibin A), all in combination with maternal age. Other factors that can usefully be taken into account in screening are maternal weight, the presence of insulin dependent diabetes mellitus, multiple pregnancy, ethnic origin, previous Down's syndrome pregnancy, and whether the test is the first one in a pregnancy or a repeat. Factors such as parity and smoking are associated with one or more of the serum markers, but the effect is too small to justify adjusting for these factors in interpreting a screening test.

URINARY MARKERS AND FETAL CELLS IN MATERNAL BLOOD

Urinary beta-core hCG has been investigated in a number of studies and shown to be raised in pregnancies with Down's syndrome. This area is currently the subject of active research and the use of urine in future screening programmes may be a practical possibility. Other urinary markers, such as total oestriol and free beta-hCG may also be of value. Fetal cells can be identified in the maternal circulation and techniques such as fluorescent in situ hybridisation can be used to identify aneuploidies, including Down's syndrome and trisomy 18. This approach may, in the future, be of value in screening or diagnosis. Currently, the techniques available do not have the performance, simplicity, or economy needed to replace existing methods.

DEMONSTRATION PROJECTS

Demonstration projects are valuable in determining the feasibility of screening and in refining the practical application of screening. They are of less value in determining the performance of different screening methods. Several demonstration projects have been conducted using the triple and double tests. In general, the uptake of screening was about 80%. The screen positive rates were about 5-6%. About 80% of women with positive screening results had an invasive diagnostic test, and of those found to have a pregnancy with Down's syndrome, about 90% chose to have a termination of pregnancy. ULTRASOUND MARKERS AT 15-22 WEEKS OF PREGNANCY: There are a number of ultrasound markers of Down's syndrome at 15-22 weeks, including nuchal fold thickness, cardiac abnormalities, duodenal atresia, femur length, humerus length, pyelectasis, and hyperechogenic bowel. (ABSTRA

Maternal serum screening for Down's syndrome: a survey of midwives' views

The lack of consensus regarding the implementation of maternal serum screening, has led to a widespread variation in practice. The importance of the role of midwives within the service has been recognised. All maternity units in the Northern region now have a designated 'co-ordinator' in an attempt to improve service delivery, professional liaison and training. This study was designed to obtain midwives' views about maternal serum screening in principle and to assess whether any changes had occurred since the introduction of co-ordinators. Semi-structured, postal questionnaires were sent to all midwives in one health authority for them to complete and return. Within this authority, one maternity unit offered universal screening whereas the other maintained a selective policy. Responses were obtained from 90 out of 133 (67.7%). There was almost unanimous support for the principle of screening 86 out of 90 (95.5%) and most midwives considered the offer of screening should be an NHS service, independent of age 78 out of 90 (86.7%). Half of the respondents 46 out of 90 (51.2%) reported that the introduction of a co-ordinator had been successful in improving staff education but requests for further training and updating were made by 69 out of 90 (76.6%) despite having had this organized training input: although those midwives who were regularly involved with screening made significantly fewer requests 27 out of 45 (60%). These findings confirmed our previous recommendation that ongoing responsibility for such provision would be required. The results of the study provided a useful contribution towards the review of screening policy undertaken by the health authority, as well as evidence upon which to base further development of the role of the co-ordinators in their support of midwives.

Serum screening for Down's syndrome: how much do health professionals know?

OBJECTIVE

To assess knowledge about serum screening for Down's syndrome in health professionals involved in antenatal care.

DESIGN

Postal questionnaire survey of knowledge of performance and interpretation of serum screening.

SETTING

Portsmouth and South East Hampshire health district.

POPULATION

All health professionals likely to be involved in antenatal care.

METHODS

Questionnaires were sent to all general practitioners (n = 288), hospital midwives (n = 129), community midwives (n = 71), and obstetricians (n = 29) working in the district.

MAIN OUTCOME MEASURES

Total number of correct responses given to eight factual questions and percentage of correct responses to each individual question.

RESULTS

Responses were received from 434 health professionals (84%). Fifty-nine percent of health professionals correctly answered only a half or less of the factual questions on serum screening. Questions relating to the sensitivity, specificity, and positive predictive value were particularly poorly answered. Obstetricians scored most highly. General practitioners scored significantly less than the other groups.

CONCLUSIONS

Women need accurate information to give informed consent to serum screening. Most health professionals likely to be involved in antenatal care in this district do not fully understand the test and are thus unlikely to provide such information. Changes in the provision of maternity services following Changing Childbirth may increase the input of midwives and general practitioners. Training of professionals about serum screening should be reviewed.

Strategies for antenatal detection of Down's syndrome

AIM

To predict the effect of maternal serum screening and fetal echocardiography on the birth prevalence of Down's syndrome.

METHODS

The outcome of all Down's syndrome pregnancies in the Northern Health Region between 1985 and 1991 was retrospectively ascertained. The number and outcome of all Down's syndrome pregnancies were used to define a theoretical population which would exist in the absence of screening. Published reports were used to predict the effects of screening strategies.

RESULTS

Down's syndrome was identified in 412 pregnancies of which 315 (76%) resulted in live birth. A theoretical population with no antenatal screening would be expected to produce 31 stillbirths and 381 (92%) live births affected by Down's syndrome. In the same population a programme of maternal serum screening and fetal echocardiography would lead to 155 and 14 terminations, respectively, and when combined, would reduce affected live births to 229 (56%).

CONCLUSIONS

Even if maternal serum screening and fetal echocardiography achieve their predicted potential, around half of all pregnancies affected by Down's syndrome will result in live born babies.

Screening for Down's syndrome: experience in an inner city health district

OBJECTIVE

To review the experience of Down's syndrome screening in an inner city health district.

DESIGN

In this retrospective study the names of the women were obtained from the Regional Cytogenetic Laboratory and District Down's Syndrome Register. Antenatal notes of the mothers were studied. Maternal age during the affected pregnancy, screening test performed if any, gestational age at booking and at screening, screening test results, and pregnancy outcome were reviewed.

SETTING

An inner city health district.

POPULATION

Down's syndrome cases diagnosed prenatally and postnatally.

INTERVENTIONS

None.

RESULTS

Antenatal diagnosis of Down's syndrome was made in 15/45 women (33.3%); Edwards' syndrome was diagnosed antenatally in 2/5 women. Screening was not performed in eight women (17.8%) whose infants were affected by Down's Syndrome; it was also not performed in one woman whose baby was affected by Edwards' syndrome due to late presentation to the antenatal clinic or loss of the blood sample. Nineteen women (42.2%) with a Down's syndrome pregnancy and two women with a Edwards' syndrome pregnancy had had a negative screening test. Three women had had a positive screening test but declined amniocentesis. Among those who had a screening test, the overall detection rate of screening was 48.6% (18/37) for Down's syndrome and 50% (2/4) for Edwards' syndrome. The detection rates in different ethnic groups did not show significant difference. Four women chose not to have termination following diagnosis of Down's syndrome, giving a total reduction rate of 21%.

CONCLUSION

Screening programmes for Down's syndrome have not yet resulted in a substantial reduction in the number of affected babies. In addition to trials at developing screening programmes with better detection rates, efforts should be made to improve the provision of the screening service and the quality of antenatal care in general with emphasis on early presentation and optimal understanding of the implications of the tests.

Prenatal genetic services for Down's syndrome: access and provision in 1990-1991. Steering Committee of the National Confidential Enquiry into Counselling for Genetic Disorders

OBJECTIVE

To examine access to and provision of prenatal genetic services relating to Down's syndrome.

DESIGN

Retrospective review of obstetric casenotes.

SAMPLE

Pregnancies involving Down's syndrome in England and Wales in 1990-1991 in women aged 38 or over. Information was obtained in 430 cases from a questionnaire completed by the obstetric team who were asked to provide details based only on documentation in the antenatal casenotes. The outcome of pregnancy was a termination in 268 (62%) cases, a liveborn child with Down's syndrome in 144 (34%), a stillbirth in 9 (2%), a miscarriage in 8(2%) and in one case was not known.

RESULTS

Overall, prenatal diagnosis was not offered in 7% pregnancies (95% CI: 4.4-9.2%) with late booking given as the main reason. Of women offered prenatal diagnosis, 76% accepted (95% CI: 72.3-80.6%). Counselling was documented before prenatal diagnosis in 89% of cases (95% CI: 86.0-92.3%) and after the procedure, to discuss the results, in 73% (95% CI: 67.5-77.7%). In 10% of pregnancies terminated for Down's syndrome, fetal products were not sent to the laboratory. There was no report of a normal fetus having been terminated as a consequences of incorrect prenatal diagnosis. However, in 10% (95% CI: 5.9 to 14.0%) of cases examined in the laboratory the diagnosis of Down's syndrome could not be confirmed. Details of prenatal diagnosis were not provided in five cases where a child with Down's syndrome was born. Of the remaining 139 livebirths, prenatal diagnosis was not offered in 27 (19%) cases, offered and declined in 92 (66%) and accepted in 20 (14%). In two cases a normal fetal karyotype was reported following prenatal diagnosis.

CONCLUSIONS

The study has demonstrated that in 1990-1991: 1. There were certain shortcomings in the documentation of antenatal care; 2. Late booking was the main factor precluding the offer of prenatal diagnosis to women aged 38 or over, and 3. The rate of confirmation of Down's syndrome in terminated fetuses was incomplete.

Using decision analysis to compare policies for antenatal screening for Down's syndrome

OBJECTIVE

To compare different screening policies for Down's syndrome across a broad range of outcomes, using decision analysis, with particular reference to the role of maternal serum testing.

DESIGN

A decision tree was used to combine data from local sources and the medical literature to predict the likely frequency of several outcomes. Sensitivity analyses were used to test the robustness of the conclusions drawn.

SETTING

Oxfordshire Health Authority.

MAIN OUTCOME MEASURES

Live births with and without Down's syndrome; miscarriages with Down's syndrome; cases of Down's syndrome detected antenatally; amniocenteses performed (and associated miscarriages); direct NHS screening costs; number of women offered screening.

RESULTS

Screening policies for Down's syndrome that include serum testing can produce better population outcomes than programmes that do not. Each option for screening for Down's syndrome that we considered had significant drawbacks. In Oxfordshire, offering serum testing to women of all ages would prevent the birth of approximately one more baby with Down's syndrome per year than would a policy of screening for women aged 30 years or more. The cost of preventing this one extra Down's birth would be one or two normal babies lost after amniocentesis, 4500 blood tests for young women (with the associated anxiety and counselling), approximately 200 false positive serum test results and amniocenteses (with the associated anxiety and distress), and 90,000 pounds for the extra tests, counselling, and amniocenteses. Opinions are divided as to which policy is the better option for the population.

CONCLUSIONS

Decision analysis is a useful tool for determining the likely consequences of different policy options across a broad range of outcomes. This focuses debate and decision making on outcomes of care, which in turn makes it clear that the choice of screening programme for Down's syndrome depends on the relative importance ascribed to the different outcomes. If individuals' values vary widely it may be impossible to find one screening policy that meets the needs of all pregnant women.

Urinary multiple marker screening for Down's syndrome

We have examined the possibility of using multiple markers in maternal urine rather than serum in order to screen for Down's syndrome. Urine samples were available from 36 cases (24 Down's syndrome, five Edwards' syndrome, three Turner's syndrome, one Klinefelter's syndrome, one triploidy, one triple-X, one twin discordant for Down's syndrome) and 294 controls, including three twins. Three markers were tested: the beta-core fragment of human chorionic gonadotrophin (hCG), total oestrogen (tE) and the free alpha subunit of hCG. Levels were corrected for creatinine excretion and expressed as multiples of the gestation-specific median (MOM) level from the singleton controls. The median value for the singleton Down's syndrome cases was 6.02, 0.74, and 1.08 MOM for beta-core-hCG, tE, and alpha-hCG, respectively. The increases in beta-core-hCG and the reduction in tE levels were highly significant (P < 0.0001 and 0.005, respectively; Wilcoxon rank sum test) but the increase in free alpha-hCG was not (P = 0.40). On the basis of a mathematical model, the expected detection rate for a 5 per cent false-positive rate was 79.6 per cent for beta-core-hCG alone, which increased to 82.3 per cent when combined with tE. Aneuploidies other than Down's syndrome were characterized by low levels of tE and either low or high beta-core-hCG.

Down's syndrome births and pregnancy terminations in 1989 to 1993: preliminary findings

OBJECTIVE

To investigate changes in the numbers of Down's syndrome births and terminations of pregnancies from 1989 to 1993.

DESIGN

Data from a national register of cytogenetic diagnoses of karyotypes associated with Down's syndrome were analysed to obtain observed numbers of births and terminations of pregnancies known to be affected. Allowance was made for those cases diagnosed prenatally for whom the eventual outcome of the pregnancies had not yet been ascertained.

RESULTS

There has been an increase over the study years in the number of cytogenetic diagnoses of Down's syndrome from 1063 in 1989 to 1137 in 1993, despite an overall fall in births in England and Wales. This is largely due to the increase in antenatal screening and diagnosis, but in part also due to the rise in numbers of pregnancies at increased maternal ages. The rise in prenatally diagnosed cases, of which 92% end in termination, has been accompanied by a fall in both the estimated numbers of affected live births, from 764 in 1989 to 615 in 1993, and the rate per 1000 total live births in the same years from 1.1 to 0.9.

CONCLUSIONS

Better and speedier information on the outcome of prenatally diagnosed cases of congenital anomalies such as Down's syndrome would improve the quality of information available for those auditing genetic services or those planning for the care of survivors.

Urinary beta-core human chorionic gonadotrophin: a new approach to Down's syndrome screening

Human chorionic gonadotrophin (hCG) is the most discriminatory maternal serum marker of Down's syndrome. We have carried out a study to establish whether urinary beta-core-hCG, a major metabolic product of hCG, might be an even better marker. Urine samples were available from seven singleton pregnancies with Down's syndrome, and one each of Edwards' syndrome, triploidy, and twins discordant for Down's syndrome. beta-Core-hCG levels were corrected for creatinine and expressed as multiples of the normal gestation-specific median (MOM) level derived from 67 singleton controls. There was a highly statistically significant elevation in level among the singleton Down's syndrome cases (P < 0.0005; Wilcoxon rank sum test). All had levels exceeding 2 MOM with a median of 6.11 MOM (95 per cent confidence interval 3.7-10.0). The levels were extremely low in Edwards' syndrome (0.08 MOM) and triploidy (0.02 MOM), but the twin pregnancy discordant for Down's syndrome did not have a raised beta-core-hCG level (0.64 MOM). The findings are sufficiently encouraging to investigate the possibility of urinalysis as a routine modality in the prenatal screening for Down's syndrome and other common serious aneuploidies.

Monitoring trends in prenatal diagnosis of Down's syndrome in England and Wales, 1989-92

The national register of chromosomal anomalies that lead to Down's syndrome has enabled the monitoring of change in prenatal diagnosis for this condition, and the factors which affect the change. The proportion of cases of cytogenetically diagnosed Down's syndrome in England and Wales detected prenatally rose to 46% in 1991-2 from 31% in 1988-9, a 1.5-fold increase (95% confidence interval 1.3 to 1.7). The increase was confined to mothers under 40 years and was due to the introduction of screening by maternal serum analysis and ultrasound. Over a quarter of affected pregnancies in women aged 25-29 were detected prenatally in 1991-2 compared with less than 10% in 1988-9. Analysis of the data showed regional differences in prenatal diagnosis rates, and in the length of time elapsing between the diagnostic test and termination of an affected pregnancy. An inexplicable finding was that this period varied with the sex of the fetus, being on average a day longer for females than for males.

Serum screening for Down's syndrome: experiences of obstetricians in England and Wales

OBJECTIVES

To assess the experiences of obstetricians in England and Wales of serum screening for Down's syndrome.

DESIGN

Postal questionnaire survey.

SUBJECTS

Questionnaires were sent to all practising obstetricians in England and Wales with nonacademic appointments who had not participated in an earlier (randomly sampled) survey of obstetricians' attitudes (n = 555). Responses were received from 393 (71%), of which 351 were analysed. The data represent about one third of obstetric consultants in England and Wales.

MAIN OUTCOME MEASURES

The extent of use of serum screening for Down's syndrome, and the problems encountered.

RESULTS

Serum screening for Down's syndrome was being offered on some basis by virtually all obstetricians in the survey. Nearly half the sample said that they did not have adequate resources for counselling all the women to whom screening was offered. Many problems were reported, which in all cases were more common than equivalent problems encountered with serum screening for neural tube defects. Over 80% (289) said that women not understanding the test was a problem.

CONCLUSIONS

There is considerable confusion associated with serum screening for Down's syndrome. The precedent of serum screening for neural tube defects does not seem to have lessened the problems experienced, rather the contrary. Many obstetricians report inadequate resources for counselling, which is consistent with the high prevalence of problems associated with women not understanding the test. There is an urgent need to consider what counselling should consist of and who should undertake it and to ensure that necessary resources are available.

Value of maternal serum unconjugated oestriol measurement in prenatal screening for Down's syndrome

We compared the medical and financial cost-effectiveness of prenatal serum screening for Down's syndrome using maternal age, serum alpha-fetoprotein and human chorionic gonadotrophin with and without the use of unconjugated oestriol. The use of unconjugated oestriol is medically more cost-effective than screening without it at all levels of detection. The actual performance depends on whether gestational age is estimated using 'dates' or an ultrasound scan. At a detection rate of 60 per cent, the proportion of unaffected fetal losses per case diagnosed at amniocentesis is about 22 per cent less if gestational age is estimated using dates (time since the first day of the last menstrual period) and about 47 per cent less if it is based on an ultrasound scan examination. At this detection rate, the inclusion of unconjugated oestriol increases costs by about 2k pounds per case diagnosed (36k pounds instead of 34k pounds) if gestational age is estimated using dates, but it is no more expensive if gestational age is measured from an ultrasound scan examination (indeed, it is more cost-effective at detection rates above 60 per cent). Since there is little change in the financial cost with the inclusion of unconjugated oestriol, for the improved medical performance of screening, it is worthwhile including it in the screening test.

Four-marker serum screening for Down's syndrome

The value of measuring the separate sub-units of human chorionic gonadotrophin (free alpha-hCG and free beta-hCG) instead of total hCG together with alpha-fetoprotein (AFP) and unconjugated oestriol (uE3) was examined to determine the effect on the performance of serum screening for Down's syndrome between 15 and 22 weeks of pregnancy. The study was based on stored serum samples relating to 75 singleton pregnancies with fetal Down's syndrome and 367 unaffected singleton pregnancies, matched for maternal age, gestational age, and duration of storage of the serum sample, supplemented by data from 970 white women with unaffected pregnancies. Using the four serum markers AFP, uE3, free beta-hCG, and free alpha-hCG, in addition to maternal age, 65 per cent of Down's syndrome pregnancies were detected for a 5 per cent false-positive rate compared with 59 per cent with the conventional triple test (AFP, uE3, total hCG with maternal age). If gestation was based on an ultrasound scan examination, the detection rate was 72 per cent using the four serum markers compared with 67 per cent with the triple test. As an alternative illustration, if the detection rate was kept at 60 per cent and gestation was estimated by an ultrasound scan examination the four-marker test reduced the false-positive rate by one-third from 3 per cent using the triple test to 2 per cent with the four-marker test. Screening performance was hardly affected by adjusting marker levels for maternal weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Variation in prenatal cytogenetic diagnosis: policies in 13 European countries, 1989-1991. EUROCAT Working Group. European Registration of Congenital Anomalies

The livebirth prevalence of autosomal chromosomal anomalies is determined by several factors, including maternal age distribution and the impact of prenatal cytogenetic diagnosis (PCD). The impact of PCD varies between countries, as the indications and the uptake vary. In a previous study we described differences in Down syndrome prevalence and the proportion of older mothers. We have now made a survey of the official PCD policies in 25 regions in 13 European countries for the period 1989-1991. In two countries, termination of pregnancy was not available. In the other 11 countries, international agreement existed on five indications: advanced maternal age, a previous child with a chromosomal anomaly, parents who are carries of a balanced translocation, mothers who are carriers of an X-linked disorder, and malformations at ultrasound. The exact limit for advanced maternal age varied from 35 to 38 years. There was a considerable variation for the indications advanced paternal age, amniocentesis for AFP or DNA, parental anxiety, a previous child with a congenital anomaly, abnormal maternal serum markers, and exposure to radiation/chemotherapy. The PCD uptake for mothers above the maternal age limit varied from 10 to 88 per cent. International harmonization of the indications for PCD is not considered feasible at present, because of the rapid changes in PCD policies even within countries.

Testing for fetal abnormality in routine antenatal care

The detection of fetal abnormality is a major component of routine antenatal care. A variety of techniques are now in use, although these are constantly being modified in the pursuit of more accurate and earlier detection. In this paper we draw attention to the distinction between screening and diagnostic tests, and describe the techniques which have been most commonly used in the UK: serum-screening for neural tube defects; screening for Down's syndrome; ultrasound scanning; amniocentesis and chorionic villus sampling.

Serum screening for Down's syndrome: some women's experiences

OBJECTIVES

To describe the experiences of a small group of women who had positive results after serum screening for Down's syndrome.

DESIGN

Semistructured telephone interviews and correspondence with women after a positive screening result (four women) negative amniocentesis results (eight), or termination of a pregnancy with a confirmed abnormality (eight).

SUBJECTS

20 women who contacted Support After Termination For Abnormality about their experiences of serum screening for Down's syndrome.

MAIN OUTCOME MEASURES

Women's knowledge and understanding of the test; staff misconceptions; communication of results; how women coped with the diagnostic process; attitudes to the test and to termination of abnormal fetuses.

RESULTS

All women were made anxious by their positive screening test, no matter how they were told. The women's experiences suggested that medical staff were unclear about the implications of screening tests and how to interpret risk. Even after receipt of negative amniocentesis results some women remained anxious. Staff did not always recognise women's concerns while awaiting amniocentesis results.

CONCLUSIONS

The way in which serum screening is being implemented does not always meet the needs of women with positive results. Some of the problems were not specific to screening for Down's syndrome. When screening tests are introduced policies should be adopted to ensure appropriate support for participants.