| pubmed-article:12424764 | pubmed:abstractText | Women having access to prenatal care late in pregnancy may still wish to benefit from maternal serum screening for Down syndrome. Therefore, we established reference values for alpha-feto protein (AFP) and free beta-human chorionic gonadotrophin (beta-hCG), and assessed the diagnostic value of maternal serum marker screening at 18-35 weeks' gestation based upon a series of 4072 sera from unaffected pregnancies and 118 sera from pregnant women with fetuses affected by Down syndrome. Using a 1/250 risk cut-off, a detection rate of 72.9% (95% CI = 71.5-74.3%) was achieved with a false-positive rate of 7.51% (95% CI = 6.71-8.3%). This was not significantly different from the percentages observed in our 14-17 weeks routine screening (50 596 patients): 71.9% (95% CI = 71.5-72.3%) and 6.48% (95% CI = 6.28-6.68%), respectively. Detection and screen-positive rates were, respectively, 51.3% (95% CI = 35.6-67.0%) and 5.95% (95% CI = 5.12-6.68%) in women aunder 35 years of age, and 84.8% (95% CI = 76.9-92.7%) and 24% (95% CI = 20.7-27.3%) in women aged 35 years and over. In conclusion, maternal serum marker screening is feasible at 18 weeks' gestation and later, which may be of interest in selected cases. | lld:pubmed |
