New Down syndrome screening protocol encouraged. (News).
British researchers are urging that prenatal screening for Down
syndrome be based on maternal age and four markers in the mother's
blood. In a study published in the March 6 issue of the British medical
journal Lancet, Dr. Nicholas Wald and colleagues from St.
Bartholomew's and The London School of Medicine and Dentistry
assessed prenatal serum screening for Down syndrome with the quadruple
test among 46,193 pregnancies in 14 hospitals over a five-year period.
The quadruple test calculates the risk of a Down syndrome term pregnancy
based on the maternal age and concentration of four markers in maternal
serum--alpha-fetoprotein, unconjugated estriol, human chorionic
gonadotropin and inhibin-A--at weeks 14 to 22 of the pregnancy. In the
study, the quadruple screen detected Down syndrome in 81 percent of 88
pregnancies. The authors concluded that the quadruple test is a better
method of screening for Down syndrome than the use of maternal age alone
(51 percent det ection rate) and is more effective than other second
trimester screening tests, and urged that the quadruple test be the test
of choice in second trimester Down screening.