Effect of fetal diagnostic testing on birth-rate of thalassaemia major in Britain.

A programme of prospective heterozygote detection and counselling, fetal diagnostic testing, and abortion of fetuses affected by thalassaemia major introduced in Britain in 1977 has proved highly acceptable to at-risk couples of Cypriot and East African Asian origin, but less so to couples of Pakistani origin. However, many at-risk couples are still not detected prospectively, the proportion of thalassaemia-major births prevented was only 32% by the end of 1981, and there is little evidence of a further fall since then. The thalassaemia-major birth-rate had fallen by 60% in Cypriots and by 20% in East African Asians, but it had not fallen at all in Pakistanis. Improved approaches to fetal diagnosis of thalassaemia major are becoming available, so a concerted effort is needed to inform all the at-risk ethnic groups of the existence of the problem and the possibility of detection of affected fetuses.