Delay between pregnancy confirmation and sickle cell and [corrected] thalassaemia screening: a population-based cohort study

Preconception risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease

BACKGROUND

Globally, about 6% of children are born with a serious birth defect of genetic or partially genetic origin. Carrier screening or testing is one way to identify couples at increased risk of having a child with an autosomal recessive condition. The most common autosomal recessive conditions are thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease, with higher carrier rates in high-risk populations of specific ancestral backgrounds. Identifying and counselling couples at genetic risk of the conditions before pregnancy enables them to make fully informed reproductive decisions, with some of these choices not being available if testing is only offered in an antenatal setting. This is an update of a previously published review.

OBJECTIVES

To assess the effectiveness of systematic preconception genetic risk assessment to enable autonomous reproductive choice and to improve reproductive outcomes  in women and their partners who are both identified as carriers of thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease in healthcare settings when compared to usual care.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Registers. Date of latest search of the registers: 04 August 2021. In addition, we searched for all relevant trials from 1970 (or the date at which the database was first available if after 1970) to date using electronic databases (MEDLINE, Embase, CINAHL, PsycINFO), clinical trial databases (National Institutes of Health, Clinical Trials Search portal of the World Health Organization, metaRegister of controlled clinical trials), and hand searching of key journals and conference abstract books from 1998 to date (European Journal of Human Genetics, Genetics in Medicine, Journal of Community Genetics). We also searched the reference lists of relevant articles, reviews and guidelines and also contacted subject experts in the field to request any unpublished or other published trials. Date of latest search of all these sources: 25 June 2021.  SELECTION CRITERIA: Any randomised controlled trials (RCTs) or quasi-RCTs (published or unpublished) comparing reproductive outcomes of systematic preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease when compared to usual care.

DATA COLLECTION AND ANALYSIS

We identified 37 papers, describing 22 unique trials which were potentially eligible for inclusion in the review. However, after assessment, we found no RCTs of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease.

MAIN RESULTS

No RCTs of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease are included. A trial identified earlier has published its results and has subsequently been listed as excluded in this review.

AUTHORS' CONCLUSIONS

As there are no RCTs of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis, or Tay-Sachs disease included in either the earlier or current versions of this review, we recommend considering potential non-RCTs studies (for example prospective cohorts or before-and-after studies) for future reviews. While RCTs are desirable to inform evidence-based practice and robust recommendations, the ethical, legal and social implications associated with using this trial design to evaluate the implementation of preconception genetic risk assessment involving carrier testing and reproductive autonomy must also be considered.  In addition, rather than focusing on single gene-by-gene carrier testing for specific autosomal-recessive conditions as the intervention being evaluated, preconception expanded genetic screening should also be included in future searches as this has received much attention in recent years as a more pragmatic strategy. The research evidence for current international policy recommendations is limited to non-randomised studies.

Antenatal haemoglobinopathy screening - Experiences of a large Australian Centre

Background

Antenatal screening is vital to identifying couples at risk of having children with a clinically significant haemoglobinopathy. In Australia, immigration is increasing carrier incidence.

Methods

A retrospective analysis was performed of full blood count, high-performance liquid chromatography and haemoglobin electrophoresis of women and their partners who underwent antenatal haemoglobinopathy screening over three years at a major NSW laboratory. Genetic testing results were included where available.

Results

One thousand six hundred and twenty-eight women and 729 male partners were screened at a median gestation of 14 weeks. 8.2% of women had a clinically significant result, with a median 16-day interval to partner testing. In 35% of couples screened simultaneously, the partner did not require testing. Genetic confirmatory testing was performed in 65% of high risk couples.

Conclusion

There was a significant delay to antenatal haemoglobinopathy screening for mothers, limiting time for genetic diagnosis, prenatal diagnosis and management of affected pregnancies. Screening should be performed earlier. Simultaneous couple testing is not cost-effective.

Adherence to a selective antenatal haemoglobinopathy screening policy within a tertiary level obstetric unit in Australia

BACKGROUND

Haemoglobinopathies represent the most common single gene disorder worldwide; however, significant centre to centre variations in antenatal screening practices exist.

AIMS

To assess performance of a selective antenatal haemoglobinopathy screening policy within a presumed low-prevalence Australian population. Primary outcome was the failure to screen rate for women with at least one identifiable risk factor. Secondary outcomes included outcomes of maternal screening and rates, gestations and outcomes of paternal, prenatal and neonatal testing.

MATERIALS AND METHODS

A two-year retrospective cohort study identifying all women attending for public antenatal care with at least one identifiable risk factor for haemoglobinopathy.

RESULTS

At least one risk factor for haemoglobinopathy was identified in 8.8% of the entire pregnant cohort; however, the failure to screen rate was high at 83.7% overall. Screening was significantly more likely to be undertaken in multiparous women, those with multiple risk factors and women originating from the Middle East. Twenty percent of screened women returned an abnormal result; however, this led to paternal haemoglobinopathy screening in only 66.6%. Where completed, the addition of partner screening reclassified offspring to low-risk status in 85.7% of cases.

CONCLUSIONS

This study demonstrates an 83.7% screen failure rate within a selective screening model raising concerns regarding the clinical utility and health equity of this approach. This major drawback of selective screening suggests that institution of a universal antenatal screening system for haemoglobinopathies, even in anticipated low-prevalence areas, will improve detection rates and ensure families receive appropriate and timely counselling.

Preconception risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease

BACKGROUND

Globally, about five per cent of children are born with congenital or genetic disorders. The most common autosomal recessive conditions are thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease, with higher carrier rates in specific patient populations. Identifying and counselling couples at genetic risk of the conditions before pregnancy enables them to make fully informed reproductive decisions, with some of these choices not being available if genetic counselling is only offered in an antenatal setting. This is an update of a previously published review.

OBJECTIVES

To assess the effectiveness of systematic preconception genetic risk assessment to improve reproductive outcomes in women and their partners who are identified as carriers of thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease in healthcare settings when compared to usual care.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Registers. In addition, we searched for all relevant trials from 1970 (or the date at which the database was first available if after 1970) to date using electronic databases (MEDLINE, Embase, CINAHL, PsycINFO), clinical trial databases (National Institutes of Health, Clinical Trials Search portal of the World Health Organization, metaRegister of controlled clinical trials), and hand searching of key journals and conference abstract books from 1998 to date (European Journal of Human Genetics, Genetics in Medicine, Journal of Community Genetics). We also searched the reference lists of relevant articles, reviews and guidelines and also contacted subject experts in the field to request any unpublished or other published trials.Date of latest search of the registers: 20 June 2017.Date of latest search of all other sources: 16 November 2017.

SELECTION CRITERIA

Any randomised or quasi-randomised controlled trials (published or unpublished) comparing reproductive outcomes of systematic preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease when compared to usual care.

DATA COLLECTION AND ANALYSIS

We identified 25 papers, describing 16 unique trials which were potentially eligible for inclusion in the review. However, after assessment, no randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease were found.

MAIN RESULTS

No randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease were included. One ongoing trial has been identified which may potentially eligible for inclusion once completed.

AUTHORS' CONCLUSIONS

As no randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis, or Tay-Sachs disease were found for inclusion in this review, the research evidence for current policy recommendations is limited to non-randomised studies.Information from well-designed, adequately powered, randomised trials is desirable in order to make more robust recommendations for practice. However, such trials must also consider the legal, ethical, and cultural barriers to implementation of preconception genetic risk assessment.

Preconception risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease

BACKGROUND

Globally, about five per cent of children are born with congenital or genetic disorders. The most common autosomal recessive conditions are thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease, with higher carrier rates in specific patient populations. Identifying and counselling couples at genetic risk of the conditions before pregnancy enables them to make fully informed reproductive decisions, with some of these choices not being available if genetic counselling is only offered in an antenatal setting.

OBJECTIVES

To assess the effectiveness of systematic preconception genetic risk assessment to improve reproductive outcomes in women and their partners who are identified as carriers of thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease in healthcare settings when compared to usual care.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Registers. In addition, we searched for all relevant trials from 1970 (or the date at which the database was first available if after 1970) to date using electronic databases (MEDLINE, Embase, CINAHL, PsycINFO), clinical trial databases (National Institutes of Health, Clinical Trials Search portal of the World Health Organization, metaRegister of controlled clinical trials), and hand searching of key journals and conference abstract books from 1998 to date (European Journal of Human Genetics, Genetics in Medicine, Journal of Community Genetics). We also searched the reference lists of relevant articles, reviews and guidelines and also contacted subject experts in the field to request any unpublished or other published trials.Date of latest search of the registers: 25 June 2015.Date of latest search of all other sources: 10 December 2014.

SELECTION CRITERIA

Any randomised or quasi-randomised control trials (published or unpublished) comparing reproductive outcomes of systematic preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease when compared to usual care.

DATA COLLECTION AND ANALYSIS

We identified 19 papers, describing 13 unique trials which were potentially eligible for inclusion in the review. However, after assessment, no randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease were found.

MAIN RESULTS

No randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease were found.

AUTHORS' CONCLUSIONS

As no randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis, or Tay-Sachs disease were found for inclusion in this review, the research evidence for current policy recommendations is limited to non-randomised studies.Information from well-designed, adequately powered, randomised trials is desirable in order to make more robust recommendations for practice. However, such trials must also consider the legal, ethical, and cultural barriers to implementation of preconception genetic risk assessment.

Offering antenatal sickle cell and thalassaemia screening in primary care: a pre-post evaluation of a brief type of communication skills training

OBJECTIVE

To evaluate brief communication skills training for healthcare professionals (HCPs) in offering antenatal sickle cell and thalassaemia (SCT) screening in primary care.

DESIGN

Descriptive study within a cluster randomised controlled trial in 17 inner city practices.

METHODS

126 HCPs were invited to attend a training session. Outcome measures were: attendance; perceived usefulness of training; comfort and confidence in offering screening; offering screening at pregnancy confirmation consultations; gestational age at test uptake.

RESULTS

62% (78/126) HCPs attended training and 61 completed both pre- and post-training questionnaires. There were 49 new joiners and locums not in post at the start of the trial. After training, HCPs reported greater comfort [4.8 vs 5.4, p = 0.05] and confidence [4.6 vs 5.6, p<0.001] in offering screening. Pregnant women consulting trained HCPs were offered screening more frequently and at an earlier gestational age than those consulting untrained HCPs (75% vs 44%, χ(2) = 122, p<0.001; 91.5 days (attending training) vs 98.5 days (did not attend training) vs 101.8 days (new joiners and locums), F = 8.49, df 1069,2 p = 0.001).

CONCLUSION

Brief communication skills training for HCPs in offering antenatal SCT screening in primary care is feasible and can be effective.

PRACTICE IMPLICATIONS

Ways of maximising HCP attendance in training sessions requires consideration.

A systematic review of issues around antenatal screening and prenatal diagnostic testing for genetic disorders: women of Asian origin in western countries

Antenatal screening has become standard practice in many countries. However, not all pregnant women choose to be tested. In the UK, the incidence of some birth defects is found to be higher in babies of Asian women than in those of women from other ethnic groups, while there is some evidence suggesting that ethnic minorities, especially Asian women, are less likely to undergo antenatal screening and prenatal diagnosis, the reasons for which are unclear. This study aims to identify and describe the literature on issues around antenatal screening and prenatal diagnostic testing for genetic disorders among women of Asian descent in western countries. The Medline, CINAHL, ASSIA and PsycInfo databases were searched for the period of 1995 and 2010. Twenty-one studies met the inclusion criteria and were therefore reviewed. In general, Asian women were found to hold favourable attitudes towards testing. However, they reported a poorer understanding of testing than white women and not being offered a test, and were less able to make informed choices. Asian women in the UK and Australia were found to be less likely than their white counterparts to have undergone prenatal diagnosis, while such differences were not found in the USA and Canada. The equity of access to quality antenatal care, alongside comprehensive well thought out antenatal screening programmes, can be assured if strategies are in place which actively involve all ethnic groups and take account of social and cultural appropriateness for the population served. An understanding of broad factors that inform women's decision-making on test uptake would help health professionals provide women and their families with more culturally sensitive information and support that they may additionally need to make more informed choices.

Screening for sickle cell and thalassaemia in primary care: a cost-effectiveness study

BACKGROUND

Haemoglobinopathies, including sickle cell disease and thalassaemia (SCT), are inherited disorders of haemoglobin. Antenatal screening for SCT rarely occurs before 10 weeks of pregnancy.

AIM

To explore the cost-effectiveness of offering SCT screening in a primary care setting, during the pregnancy confirmation visit.

DESIGN AND SETTING

A model-based cost-effectiveness analysis of inner-city areas with a high proportion of residents from ethnic minority groups.

METHOD

Comparison was made of three SCT screening approaches: 'primary care parallel' (primary care screening with test offered to mother and father together); 'primary care sequential (primary care screening with test offered to the mother and then the father only if the mother is a carrier); and 'midwife care' (sequential screening at the first midwife consultation). The model was populated with data from the SHIFT (Screening for Haemoglobinopathies In First Trimester) trial and other sources.

RESULTS

Compared to midwife care, primary care sequential had a higher NHS cost of £34,000 per 10,000 pregnancies (95% confidence interval [CI] = £15,000 to £51,000) and an increase of 2623 women screened (95% CI: 1359 to 4495), giving a cost per additional woman screened by 10 weeks of £13. Primary care parallel was dominated by primary care sequential, with both higher costs and fewer women screened.

CONCLUSION

The policy judgement is whether an earlier opportunity for informed reproductive choice has a value of at least £13. Further work is required to understand the value attached to earlier informed reproductive choices.

Offering antenatal sickle cell and thalassaemia screening to pregnant women in primary care: a qualitative study of GPs' experiences

BACKGROUND

Timely antenatal sickle cell and thalassaemia (SC&T) screening for all women in primary care facilitates informed decision making, but little is known about its implementation.

AIM

To assess the feasibility of offering antenatal SC&T screening in primary care at the time of pregnancy confirmation.

DESIGN OF STUDY

Cross-sectional investigation of GPs' beliefs and perceived practices.

METHOD

Informal face-to-face interviews with 34 GPs.

SETTING

Seventeen inner-city general practices that offered antenatal SC&T screening as part of a trial.

RESULTS

GPs identified both barriers and facilitators. Organisational barriers included inflexible appointment systems and lack of interpreters for women whose first language was not English. Professional barriers included concerns about raising possible adverse outcomes in the first antenatal visit. Perceived patient barriers included women's lack of awareness of SC&T. Hence, GPs presented the test to women as routine, rather than as a choice. Organisational facilitators included simple and flexible systems for offering screening in primary care, practice cohesion, and training. Professional facilitators included positive attitudes to screening for SC&T. Perceived patient facilitators included women's desire for healthy children.

CONCLUSION

GPs reported barriers, as well as facilitators, to successful implementation but the extent to which screening could be regarded as offering 'informed choice' remained fundamental when making sense of these barriers and facilitators.

Effectiveness of earlier antenatal screening for sickle cell disease and thalassaemia in primary care: cluster randomised trial

OBJECTIVE

To evaluate the effectiveness of offering antenatal screening for sickle cell disease and thalassaemia in primary care as a way of facilitating earlier uptake of screening.

DESIGN

Partial factorial cluster randomised controlled trial.

SETTING

25 UK general practices from deprived inner city areas.

PARTICIPANTS

Anonymised data on all pregnant women attending participating practices during a six month period before randomisation and a seven month period after randomisation. This included 1708 eligible women.

INTERVENTION

Practices were randomised to three groups for seven months: parallel testing in general practice (tests for sickle cell disease and thalassaemia offered to both parents when pregnancy was first reported); sequential testing in general practice (tests offered to mothers when pregnancy was first reported, and subsequently to the partners of women who were found to be carriers); and midwife care (tests offered to mothers at first consultation with a midwife).

MAIN OUTCOME MEASURES

The primary outcome (available for all women) was the proportion of eligible women screened before 10 weeks' (70 days') gestation. Secondary outcomes were an offer of screening to women before 10 weeks' gestation, gestational age at testing, mean interval from first visit to the general practice visit to screening, and women's knowledge of the carrier status of their baby's father before 77 days' (11 weeks') gestation. The study was designed to detect a 20% absolute increase in screening uptake. Cluster level analyses were adjusted for age group, parity, ethnic group, primary care organisation, and number of general practitioners per practice.

RESULTS

Data were analysed for 1708 eligible women. In the midwife care arm, 2% (9/441) of women were screened before 10 weeks' gestation compared with 24% (161/677) in the GP parallel testing arm and 28% (167/590) in the GP sequential testing arm. The estimated adjusted difference between the midwife care and GP parallel testing arms was 16.5% (95% confidence interval 7.1% to 25.8%; P=0.002) and between the midwife care and GP sequential testing arms was 27.8% (14.8% to 40.7%; P<0.001). By 26 weeks' gestation the proportion of women screened across the three trial arms was similar (81%). The proportion of women who knew the carrier status of the baby's father by 11 weeks' gestation was 0% (0/441) in the midwife care arm, 2% (13/677) in the GP parallel testing arm (P=0.003), and 1% (3/590) in the GP sequential testing arm (P=0.374).

CONCLUSION

Offering antenatal screening for sickle cell disease and thalassaemia as part of consultations for pregnancy confirmation in primary care increases the proportion of women screened before 10 weeks' gestation. Even with intervention, however, only a minority of women were screened before 10 weeks. Additional interventions should be considered to achieve testing early in pregnancy for most women wanting such tests so that couples with affected pregnancies have less time pressure to choose options, which may include termination of the pregnancy.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN00677850.

Preimplantation genetic diagnosis for the prevention of sickle cell disease: current trends and barriers to uptake in a London teaching hospital

INTRODUCTION

Sickle cell disease (SCD) is a clinically significant hemoglobinopathy with increasing global incidence. We describe our experience of using pre-implantation genetic diagnosis (PGD) for the prevention of SCD at a tertiary referral centre in London.

METHODS

Between January 2002 and December 2007, of 78 at-risk couples referred for PGD treatment, 12 couples (15%) underwent 16 PGD cycles for the prevention of SCD. RESULTS. The live birth rate was 13% per initiated cycle, 18% per embryo transfer and 17% per couple.

CONCLUSIONS

Although PGD for prevention of the birth of a child affected by SCD is a viable treatment option for couples at risk of having an affected child, potential barriers to uptake of this service need to be fully addressed to ensure its availability to all couples seeking to avoid having a child affected with SCD.

Maximising recruitment and retention of general practices in clinical trials: a case study

BACKGROUND

There is limited evidence regarding the factors that facilitate recruitment and retention of general practices in clinical trials. It is therefore pertinent to consider the factors that facilitate research in primary care.

AIM

To formulate hypotheses about effective ways of recruiting and retaining practices to clinical trials, based on a case study.

DESIGN OF STUDY

Case study of practice recruitment and retention to a trial of delivering antenatal sickle cell and thalassaemia screening.

SETTING

Two UK primary care trusts with 123 practices, with a high incidence of sickle cell and thalassaemia, and high levels of social deprivation.

METHOD

Practices were invited to take part in the trial using a research information sheet for practices. Invitations were sent to all practice managers, GPs, practice nurses, and nurse practitioners. Expenses of approximately pound 3000 per practice were available. Practices and the research team signed research activity agreements, detailing a payment schedule based on deliverables. Semi-structured interviews were completed with 20 GPs who participated in the trial. Outcome measures were the number of practices recruited to, and completing, the trial.

RESULTS

Four practices did not agree to randomisation and were excluded. Of 119 eligible practices, 29 expressed an interest in participation. Two practices withdrew from the trial and 27 participated (two hosted pilot studies and 25 completed the trial), giving a retention rate of 93% (27/29). The 27 participating practices did not differ from non-participating practices in list size, number of GPs, social deprivation, or minority ethnic group composition of the practice population.

CONCLUSION

Three factors appeared important in recruiting practices: research topic, invitation method, and interest in research. Three factors appeared important in retaining practices: good communication, easy data-collection methods, and payment upon meeting pre-agreed targets. The effectiveness of these factors at facilitating recruitment and retention requires assessment in experimental studies.