Antenatal haemoglobinopathy screeningBMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c5243 (Published 18 October 2010) Cite this as: BMJ 2010;341:c5243
The haemoglobinopathies, sickle cell disease and β thalassaemia major, are autosomal recessive diseases. In the United Kingdom, about 240 000 people are healthy carriers of sickle cell gene variants and 12 500 have the disease; β thalassaemia is less common, with 214 000 healthy carriers and 700 patients affected by illness.1 The NHS screening programme for sickle cell disease and thalassaemia was set up in 2001 on evidence from systematic reviews.2 It aims to offer screening before 10 weeks of pregnancy to all women in England, in addition to neonatal blood spot screening.3 Screening couples before 12 weeks provides the opportunity to discuss all the reproductive choices available, including prenatal diagnosis and termination of pregnancy. In the linked randomised controlled trial (doi:10.1136/bmj.c5132), Dormandy and colleagues assess whether offering screening in primary care facilitates earlier uptake of screening⇓.
A problem exists with antenatal screening for sickle cell disease and thalassaemia. Previous research in a high prevalence area has shown that although most women visit their general practitioner early (median gestation 7.6 weeks) screening is significantly delayed (median gestation 15.3 weeks).4 Although 74% of women presented in time only 5% were screened before 10 weeks.
The present study attempted to tackle this problem. Three antenatal screening strategies were compared: parallel testing in general practice, where screening was offered to both parents when pregnancy was first confirmed; sequential testing in general practice, where screening was offered to mothers at first presentation and then to the partners of screen positive women; and midwifery care, where screening was offered when the woman first presented to the midwife.5 Around 24% and 28% of women were screened before 10 weeks in the parallel and sequential arms, respectively, significantly more than the 2% in the midwifery arm. The proportion of women screened by 26 weeks was similar in all three groups (81%); this indicates that the women did not differ in their willingness to be screened. The uptake of screening by partners was very low in all three groups. The research design included training and support for recruited practices; in usual practice the results would probably be even worse.
Other evidence indicates that health professionals rather than pregnant women are responsible for the delay in screening.6 7 In a study of antenatal screening for Down’s syndrome, women from ethnic or socioeconomically disadvantaged groups (or both) were less likely to be screened than other women, not because they had more negative attitudes to screening, but because they had lower testing rates.8 The reasons for this are unclear but probably reflect language problems and cultural differences.
The full report of the linked study explores barriers to screening for sickle cell disease and thalassaemia by general practitioners.9 These include lack of time within the 10 minute consultation, delays in arranging blood tests, language problems, and negative professional attitudes. In another study, general practitioners reported a lack of confidence and knowledge about communicating basic genetic information to women and families at risk, and a lack of knowledge of the importance of rapid referral to prenatal diagnostic services.10
If the results for general practitioners are poor, those for midwives are even worse. This may be the perverse effect on midwives of a national target that makes “booking” women by 12 weeks of completed pregnancy more important than seeing women early, especially when there are workload pressures and recruitment difficulties.
Preconception testing may be more acceptable culturally and ethically to some women and men. The experience from Cyprus, where the prevalence of the thalassaemia carrier state is higher, is compelling: there has been an intensive educational campaign and preconception screening policy since the 1970s, and babies with thalassaemia are now uncommon there. Most Cypriots living in the UK request preconception screening, unlike South East Asian people, whose awareness of the risk is poor.11 It is clearly important to raise awareness within ethnic populations. In the voluntary sector, the Sickle Cell Society and Thalassaemia UK have active educational campaigns that aim to do just this and to encourage early testing.
What are the implications of this study for general practitioners? The role of general practitioners in maternity care has changed greatly over the past 20 years; in current practice they rarely do more than signpost to midwives.12 The challenge is to re-engage general practitioners in early maternity care and to raise their awareness and skills. The NHS sickle cell disease and thalassaemia screening programme provides patient information in different languages and training is offered through PEGASUS (www.pegasus.nhs.uk/index.php). Future technological advances may make it easier to do rapid tests on blood spots or saliva, but unless the tests are offered they won’t happen. Antenatal screening for sickle cell disease and thalassaemia is just the tip of a genetic iceberg and primary care needs to be prepared.
General practitioners provide lifelong care and haemoglobinopathy testing is a “test for life,” not just for pregnancy. Done once and computer coded properly, sickle cell disease and thalassaemia screening does not need repeating. Men as well as women need to consider their genetic heritage. General practitioners have many opportunities to raise the subject of haemoglobinopathy testing whenever they see young people—for example, when giving contraception advice.
Antenatal screening for sickle cell disease and thalassaemia is an important and worthwhile programme, but it cannot be successful unless general practitioners take responsibility for testing or midwives book women earlier, or both. The current low level of uptake of early screening is unacceptable; we are failing women with affected pregnancies, who cannot make reproductive choices if professionals “miss the boat.” It may be that the only way to facilitate this change is through an incentive scheme, such as the Quality and Outcomes Framework.
Cite this as: BMJ 2010;341:c5243
Competing interests: The author has completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work
Provenance and peer review: Commissioned; not externally peer reviewed.