Related Experiment Video
Updated: Apr 18, 2026
Chromosome Screening of Human Preimplantation Embryos by Using Spent Culture Medium: Sample Collection and Chromosomal Ploidy Analysis
Published on: September 7, 2021
Chromosome abnormalities diagnosed in utero: a Japanese study of 28 983 amniotic fluid specimens collected before 22
Miyuki Nishiyama1, Jim Yan2, Junko Yotsumoto3
1Department of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan.
Abstract:
To investigate the frequency and type of abnormal karyotype in Japan by amniocentesis before 22 weeks of gestation. We performed a retrospective analysis of 28 983 amniotic fluid specimens in a local population collected before 22 weeks gestations for fetal karyotyping. The incidence of abnormal karyotype was 6.0%. The main indication was advanced maternal age (AMA) of 35 years and older, which represented over half of the clinical indications. Abnormal karyotype was most frequently reported among the referrals for abnormal ultrasound findings (21.8%), followed by positive maternal serum screen results (5.3%). Three-fourths of abnormal karyotype was either autosomal aneuploidy (64.0%) or sex chromosome aneuploidy (11.6%). Abnormal karyotype was detected in 2.8% of pregnant women referred for AMA. Clinically significant abnormal karyotype increased with advancing maternal age. The frequency and type of abnormal karyotype detected by amniocentesis for various indications were determined. Amniocentesis was mainly performed among the referrals for AMA, which is a characteristic distribution of indications of Japan.
