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

Research output: Contribution to journalArticle


  • E Dormandy
  • M Gulliford
  • S Bryan
  • M Calnan
  • K Atkin
  • J Karnon
  • J Logan
  • F Kavalier
  • HJ Harris
  • TA Johnston
  • EN Anionwu
  • V Tsianakas
  • P Jones
  • TM Marteau


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


Original languageEnglish
Article numberc5132
JournalBritish Medical Journal (International edition)
Issue number7779
Publication statusPublished - 1 Oct 2010