J Genet Med.  2008 Dec;5(2):125-130.

Midtrimester Amniocentesis for Prenatal Diagnosis

• Kim SR
• Choi EJ
• Kim TY
• Kwon KH
• Song NH
• Oh SK
• Chi HJ

Abstract

PROPOSE: To analyze the indications and cytogenetic results of midtrimester amniocentesis. MATERIAL AND METHODS: This study reviewed 2,523 cases of midtrimester prenatal genetic amniocentesis performed at MizMedi Hospital between January 2000 and December 2007.
RESULTS
The most frequent indication for midtrimester amniocentesis was advanced maternal age (45.9%), followed by positive serum markers (29.9%). Chromosomal aberrations were diagnosed in 110 cases (4.4%), for which numerical aberration accounted for 38 cases (34.5%), structural aberration accounted for 65 cases (59.1%), and mosaicism accounted for 7 cases (6.4%). Among the autosomal aberrations, there were 20 cases of trisomy 21 and 8 cases of trisomy 18. With respect to structural aberrations, there were 14 cases of reciprocal translocation and 8 cases of robertsonian translocation. The frequencies of chromosomal aberrations according to the indication were highest in individuals with a family history of chromosome abnormality 14.0% (8/57) followed by previous congenital anomaly 5.9% (2/34).
CONCLUSION
Midtrimester amniocentesis is an effective tool for prenatal diagnosis. Indications such as advanced maternal age, maternal serum markers, and ultrasound are important for predicting abnormal fetal karyotypes.

Keyword

Amniocentesis; Chromosomal abnormality

MeSH Terms

Amniocentesis
Biomarkers
Chromosome Aberrations
Cytogenetics
Down Syndrome
Female
Humans
Karyotype
Maternal Age
Mosaicism
Pregnancy
Pregnancy Trimester, Second
Prenatal Diagnosis
Trisomy