UNLABELLED: The role of ultrasound examination in second trimester screening for fetal aneuploidies.OBJECTIVE: Authors sought to determine the frequency of ultrasound findings in major chromosomal defects. They also tried to evaluate possible patterns of ultrasound signs of fetal chromosomal defects.METHODS: Through the time period of 15 years (1999-2004) 22,150 fetal karyotypings were done, and 514 abnormal karyotypes (2.3%, 514/22,150) were diagnosed prenatally. Congenital anomalies of these fetuses, detected by second trimester sonography, were analyzed in this study.RESULTS: Of the 514 chromosome aberrations, 207 fetuses with trisomy 21 (40.3%), 70 fetuses with trisomy 18 (13.6%), 28 fetuses with trisomy 13 (5.4%), 69 fetuses with Turner syndrome (13.4%) and 12 fetuses with triploidy (2.3%) were detected. The incidences of major structural defects and minor anomalies were evaluated then ultrasound signs with the highest incidences were established in each of the major chromosomal defects.CONCLUSION: This study may help to select the "optimal components" of the genetic sonogram that would assist the counseling of women for the risk of a chromosomal abnormality. Other advantages of such approach could be the standardization of the contents of ultrasound examination among different health care providers and institutions, and a decrease in false-positive rates.
Adult Aneuploidy