THE VALUE OF SCREENING FOR DOWNS-SYNDROME IN A SOCIOECONOMICALLY DEPRIVED AREA WITH A HIGH ETHNIC-POPULATION

Objective To assess the utility of biochemical antenatal screening for Down's syndrome in a socioeconomically deprived area with a high prop ortion of Asian women from the Indian Subcontinent. Design Audit of Do wn's syndrome biochemical screening service over a four-year period. S etting Teaching hospital and community antenatal clinic in inner city Birmingham. Population Women booked between October 1992 and December 1996. Methods Blood for screening was collected between 14 and 21 week s gestation, alpha-fetoprotein and intact human chorionic gonadotrophi n were measured in serum and the risk of Down's syndrome was calculate d. Main outcome measures Uptakes of screening and amniocentesis, scree n positive rate, odds of being affected given a positive result, misca rriages associated with amniocentesis offered following a high risk re sult, detection rate, number of Down's cases prevented and a cost anal ysis. Outcome measures were compared between Asians and Caucasians. Re sults Overall 11,974 women (71%) accepted serum screening. The screen positive rate was 8.3% in Asians and 5.0% in Caucasians. The uptake of amniocentesis in women following a high risk result was 54% overall ( 35% Asian, 67% Caucasian). Nineteen cases of Down's syndrome were iden tified, of which 13 occurred in women who opted for biochemical screen ing. The detection rate of the biochemical screening programme was 85% (11/13). Of these 11 cases, six (none of whom were Asian) elected to have an amniocentesis, of whom four thereafter had a termination. Conc lusion In this study the public health benefits of screening for Down' s syndrome in a socioeconomically deprived area with a high Asian popu lation, were small.