We should be prepared to re-examine entrenched practices

Papers p 606

An important lesson in all medicine, but particularly illustrated in screening programmes, is the continued need to review and audit. Serum screening for Down's syndrome, introduced by many health authorities in the past decade, 1^–3 is a good example. The original demonstration projects compared the detection rate when Down's syndrome was identified after serum screening with earlier data derived from screening targeted towards pregnancies in older women.2 Howe et al from Southampton now challenge some of the assumptions (see p 606).4 They found that the Down's syndrome detection rate in one Southampton maternity hospital averaged 68% (and at least 41% in the pregnancies of women aged less than 35), without using serum screening. The higher detection rate without serum studies undermines the cost benefit arguments for such screening and raises questions about what to do next.

One reason for this higher than expected detection rate is a change in the age distribution of pregnant women. In the Southampton …