Clinical and Cytogenetic Analysis of Midtrimester Amniocentesis

Lee, Jin Gu; Chung, Koo Hyun; Kang, Byung Hun; Noh, Heung Tae; Rhee, Yun Ee; Gu, Seon Hoe

Abstract

OBJECTIVE
To analyze the indications, clinical features, cytogenetic results and complications of amniocentesis and to determine the efficacy of antenatal genetic amniocentesis.
METHODS
We analyzed retrospectively maternal age, gestational age, indications, transplacental puncture, frequency, discoloration of amniotic fluid, karyotype and complications in 325 cases of prenatal genetic amniocentesis performed at Chungnam National University Hospital from January 2000 to December 2002.
RESULTS
The most common age group was from 30 to 34 (31.4%) and mean age was 32.7 years old. 85.3% of cases were performed at 16th-20th gestational weeks. Abnormal maternal serum markers were the most common indication of amniocentesis (56.0%) and the second most common indication was maternal age over 35 (33.2%). Abnormal karyotypes were found in 12 cases (3.6%) and normal variants were 21 cases (6.5%). Numerical aberration were 9 cases (2.7%) and structural aberration were 3 cases (0.3%). Among the autosomal aberrations, Down syndromes were 5 cases and Edward syndrome was 1 case. Among the sex chromosomal aberrations, 47,XXX were 2 cases and Turner syndrome was 1 case. As the increasing maternal age, the incidence of abnormal karyotype was increased. Procedure-related complications occurred in 11.7% of cases and fetal loss rate was 7.4%. No significant associations were found between procedure-related complications and maternal age, gestational age, transplacental puncture, frequency, discoloration of amniotic fluid, and antibiotic treatment.
CONCLUSION
Amniocentesis is useful for prenatal genetic diagnosis in pregnancies with increasing risk of chromosome aberrations, such as advanced maternal age, abnormal maternal serum markers or abnormal US findings. Further studies are necessary to identify risk factors of complications after invasive procedure.