Clinical experience with the triple test for Down's syndrome screening.

The introduction of maternal serological screening for chromosome disorders in pregnancy in women aged over 30 years at the estimated date of delivery was monitored in two hospitals. The test used involved measurement of three substances in maternal serum combined with maternal age (the triple test). This is the first report of such screening applied to an unselected antenatal clinic population. Test uptake was high but there was no overall increase in amniocentesis numbers because the increase in younger mothers was compensated for by a decrease in older women who previously, without serological testing, might have gone directly to amniocentesis. It is anticipated that widespread introduction of such testing will lead to improved detection of Down's syndrome as predicted from retrospective studies.