Clinical significance of ultrasonic screening of fetal structural anomalies at 11-13+6 weeks

Abstract

Objective To summarize the clinical significance of ultrasonic screening of fetal structural anomalies at 11-13+6 weeks. Methods We conducted a retrospective study of 4853 cases of nuchal translucency screening at 11-13+6 weeks in Maternal and Child Health Hospital of Bao′an of Shenzhen City from September 2011 to May 2014. The screening ultrasound planes included the median sagittal plane, neck sagittal section, cerebral transverse section, cardiac four-chamber view, three-vessel-trachea view, abdominal transverse section, bladder section, upper limb section and lower limb section of the fetuses. All the cases then underwent the ultrasonic structural screening in the second trimester (20-24 weeks) and the third (28-32 weeks) trimester and were followed up until 6 weeks after birth or the biopsy after abortion. Results Eighty-five fetal structural anomalies were detected among the 4853 pregnant women at 11-13+6 weeks of gestation with the detection rate of 1.75% (85/4853), including central nervous system abnormalities (28 cases), anterior abdominal wall anomalies (9 cases), cardiac anomalies (6 cases), urinary system malformation (3 cases), skeletal system malformation (2 cases), multilocular cystic tumor and dropsy embryo (35 cases), and abnormal twins (2 cases). Among above abnormal fetuses, 6 cases showed normal structure in the screening after 14 weeks and were born without malformations, while the rest 79 cases were taken artificial abortion (73 cases in the first trimester and 6 cases in the second trimester). Only 9 cases were taken chorionic puncture or amniocentesis, including normal karyotypes (3 cases), 47, XN, +18 (3 cases) and 45, X (3 cases). The False negative rate in the first trimester was 23% (25/110). Supplementary detection of fetal structural abnormalities in the second and third trimester were found in 22 cases (20%, 22/110). Two cases of VSD and 1 case of microtia were identified after birth. Conclusions The fetal malformation can be detected in the earlier gestation with the ultrasonic screening at 11-13+6 weeks, which provide the earlier termination to the abnormal fetus. It has important clinical significance in effectively reducing fetal births with structural abnormalities. Key words: Ultrasonic screening; Fetus; Congenital anomalies