Value of second trimester serological screening of Down syndrome in pregnant women with advanced age

Abstract

Objective To evaluate the value of second trimester serological screening of Down syndrome (DS) in pregnant women with advanced age. Methods From January 2009 to December 2014, a total of 1 571 cases of pregnant women with advanced age (expected age of delivery≥35 years old) who received second trimester serological screening for DS in Department of Prenatal Diagnosis of Obstetrics and Gynecology, West China Second University Hospital were enrolled as advanced age group (n=1 571). From January to December 2012, a total of 10 881 cases of young pregnant women (expected age of delivery 0.05). Results ①Among 1 571 cases of pregnant women in advanced age group, 121 cases were in high-risk of DS serological screening, and 4 cases were diagnosed as DS; 1 450 cases were in low-risk of DS serological screening, and no fetal DS was found. Among 10 881 cases of pregnant women in young group, 759 cases were in high-risk of DS serological screening, and 6 cases were diagnosed as DS; 10 122 cases were in low-risk of DS serological screening, and 1 case were diagnosed as DS postnatally. ②In advanced age group, the false positive rate of DS serological screening was 7.4% (117/1 571), the young group was 6.9% (753/10 881), and the difference was not statistically significant (χ2=0.587, P=0.444). ③In advanced age group, DS serological screening efficiency was 3.3% (4/121), which was significantly higher than that of young group (0.8%, 6/759), and the difference was statistically significant (χ2=3.870, P=0.049). Conclusions The three-marker (β-hCG, AFP and uE3) test is an effective screen strategy for second trimester serological screening of DS in pregnant women with advanced age. It can reduce the rate of genetic amniocentesis. Key words: Down syndrome; Serological screening; Pregnancy trimester, second; Screening efficiency; False positive rate; Pregnant women, advanced