Clinical Analysis of Prenatal Cytogenetic Diagnoses: Four-year Experience at Asan Medical Center / 대한산부인과학회잡지

ABSTRACT

OBJECTIVE: To review and evaluate a total of 2,372 cases of prenatal cytogenetic diagnoses at Asan Medical Center from 1999 to 2002. METHODS: We reviewed the medical records of the patients in whom the procedure for prenatal cytogenetic diagnosis was performed. A total of 1780 cases of amniocentesis, 455 cases of cordocentesis, and 137 cases of chorionic villus sampling were analyzed. The cytogenetic results, indications for prenatal cytogenetic diagnoses, maternal ages, and the profiles of abnormal karyotypes were reviewed. We calculated the positive predictive value of each indication for abnormal fetal karyotypes and evaluated a factor that was the most sensitive marker for abnormal fetal karyotypes. RESULTS: Among the 2,372 cases of prenatal cytogenetic diagnoses, abnormal karyotypes were identified in a total of 158 cases (6.7%). The most frequent indication for prenatal cytogenetic diagnosis was abnormal maternal serum screening (33.9%), followed by ultrasonographic abnormality (22.9%) and old age (20.0%). No significant difference was found between mean maternal age with and without abnormal fetal karyotypes after excluding balanced rearrangements and polymorphisms (31.9 +/- 5.3 vs. 32.1 +/- 4.5 years). Among the 92 cases of abnormal fetal karyotypes after excluding balanced rearrangements and polymorphisms, the most frequent indication for prenatal cytogenetic diagnosis was ultrasonographic abnormality (58.7%), followed by abnormal maternal serum screening (10.9%). The positive predictive value of ultrasonographic abnormality for abnormal fetal karyotype was 9.9%. CONCLUSION: Among the several indications for prenatal cytogenetic diagnosis, ultrasonographic abnormality could be the most predictive marker for abnormal fetal karyotypes.