Currently the number of pregnant women who have indications for, but do not receive, prenatal cytogenetic diagnosis is increasing. The purpose of this study was to review the prenatal cytogenetic services and to analyze the effect of genetic counseling on performance of the prenatal cytogenetic test. From January 1987 to July 1988, there were 2,796 deliveries at Severance Hospital, Yonsei Medical Center, of which 126 patients had indications for prenatal cytogenetic diagnosis. Chromosomal abnormalities were found in 5 patients (1, monosomy X; 1, trisomy 18; and 3, trisomy 21). Four patients were found in the group who had indications for prenatal cytogenetic diagnosis while only one was found in the group who did not (p less than 0.01). The most common indication for prenatal cytogenetic diagnosis was advanced maternal age (59%). The prenatal test rate was highest in patients whose indications were a previous child with chromosomal abnormality (100%) and parental translocation carrier (100%). Most (89%) of the patients were tested by amniocentesis between the 16th and 20th week of gestation. The two most common reasons for patients not receiving a prenatal cytogenetic diagnosis were late registration (41%) and absence of genetic counseling (34%).
Abnormalities, Multiple/genetics ; Adult ; Amniocentesis ; *Cytogenetics ; Female ; *Genetic Counseling ; Heterozygote ; Human ; Maternal Age 35 and over ; Pregnancy ; *Prenatal Diagnosis ; Translocation (Genetics)

The purpose of this article is to assess the value of maternal serum triple marker screening of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) for the prenatal diagnosis of fetal chromosomal abnormalities in Korean women of advanced maternal age. Maternal sera were collected from 458 pregnant Korean women aged 35 between 15 and 20 weeks gestation before amniocentesis. A patient- specific second trimester risk for fetal Down's syndrome was calculated using the median values for AFP, hCG, uE3 and maternal age. Twelve fetal chromosomal abnormalities were identified. These included six cases of trisomy 21, one case of 46,XY/47,XY,+21, two cases of trisomy 18, one case of trisomy 13, and two cases of 45, X. A cutoff level of 1:200 detected 85.7% (6/7) of the cases of Down's syndrome and 20% (1/5) of the other aneuploidies, with a 27.3% false positive rate. However, a cutoff level of 1:270 did not result in any gains in detecting Down's syndrome or other aneuploidies at the expense of a false positive rate of 34.3%. Second trimester triple marker testing is an effective screening tool for detecting fetal Down's syndrome in Korean women > or = 35 years old. However, it is not an effective screening tool for non-Down's chromosomal abnormalities.
Adult ; Chromosome Abnormalities/genetics* ; Female ; Fetus/physiology* ; Genetic Markers ; Genetic Screening* ; Human ; Maternal Age 35 and over* ; Pregnancy