95% of women in England not screened for sickle cell anaemia or thalassaemia by 10 week target

BMJ 2008; 336 doi: (Published 28 February 2008) Cite this as: BMJ 2008;336:468
  1. Susan Mayor
  1. 1London

Most women fail to receive antenatal screening for sickle cell anaemia or thalassaemia within the recommended time of 10 weeks, a study of general practice in England has found (British Journal of General Practice 2008;58:154-9). This indicates that screening may often occur too late to allow couples a choice regarding termination of affected fetuses.

The study assessed antenatal screening for the two inherited disorders in all pregnancies reported in at least a six month period in 25 general practices of two inner city primary care trusts. They both had about 40% of their populations from minority ethnic groups and ranked among the most deprived in England.

Results from the 1441 pregnancies analysed showed that 95% of women failed to receive screening by the target of 10 weeks.

The median delay was 6.9 (interquartile range 4.7-9.3) weeks between pregnancy being confirmed and screening for sickle cell anaemia and thalassaemia. The median gestational age at screening was 15.3 (12.6-18.0) weeks. Almost three quarters of women (74%) had their pregnancy confirmed before 10 weeks’ gestation, but only 4.4% were screened by this time.

Elizabeth Dormandy, national monitoring and performance manager for the NHS sickle cell and thalassaemia screening programme and one of the study’s authors, said, “These results show that the NHS has not yet got to grips with a new generation of genetic tests. Our systems are lagging behind the new technologies.”

Dr Dormandy added, “The point of antenatal screening for sickle cell and thalassaemia is to give parents information about whether their unborn baby is at risk of inheriting a serious disease. In this case, the timing of the initial blood test is critical and delay undermines the ability to offer genuine informed choice.”

The delays in screening seemed to be associated with the organisation and delivery of antenatal care rather than factors associated with individual patients, she noted.

Allison Streetly, director of the screeningprogramme, considered that measures are urgently needed so that more women are screened by the 10 week target. “That means either providing screening in a primary care setting or minimising the delay between primary care and seeing a midwife,” she suggested.

One option would be to educate people that they can be screened at any time. “So, for example, if young people are screened before they plan a family, they can explore their options without the pressure of a developing pregnancy,” Dr Streetly said.

She hopes that updated guidelines from the National Institute for Health and Clinical Excellence about antenatal care, to be published in March, will explicitly support recommendations for early screening for sickle cell and thalassaemia and provide clear guidance on how sickle cell and thalassaemia screening fits into antenatal care as a whole.

The screening programme recommends that an initial blood test should be provided before 10 weeks of pregnancy. The father should be offered a blood test if the mother is identified as a genetic carrier, and the couple should be given specialist counselling; offered prenatal diagnosis of the fetus if both parents are identified as carriers; and offered an early termination, if needed, which should be completed before the end of 12 weeks’ gestation.

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