Clinical value of ultrasonography in screening trisomy 13 during the second and third trimesters of gestation

Objective: To investigate the clinical value of ultrasonography in screening trisomy 13 during the second and third trimesters. Methods: Amniocentesis and cordocentesis were performed on 3297 pregnant women with indications for prenatal diagnosis to detect karyotype of the fetus during second trimester and late pregnancy. The detection rates of trisomy 13 were compared among different indications of pregnant women. The relationship between the ultrasonography abnormalities and trisomy 13 was analyzed. Results: In chromosomal karyotypes analysis of 3297 pregnant women by amniocentesis and cordocentesis, 3 trisomy 13 were detected with a detection rate of 0.09%. There were 226 in 3297 pregnant women with simple ultrasonography abnormalities, and 2 of them were found with trisomy 13 with a detection rate of 0.88%. The detection rate of trisomy 13 detected with ultrasound (0.88%) was higher than that with the Down's syndrome high risk (P=0.001). Conclusion: During the second and third trimester, ultrasonography contributes to detect the trisomy.