Cytogenetic Analysis of Spontaneous Miscarriages Using Long-Term Culturing of Chorionic Villi

Abstract

Spontaneous miscarriages are strongly associated with fetal chromosomal abnormalities. We sought to validate the occurrence of chromosomal abnormalities in Japanese patients with early spontaneous miscarriages using a conventional long-term culture method. One hundred and thirty-two patients were studied after excluding 7 cases with culture failure. Chromosomal analysis of 132 cases was performed using a long-term culture method of the villous placental tissue. Patients’ age, number of previous spontaneous abortions, fetal data from ultrasonography, and the method of conception (ART or spontaneous pregnancy) were obtained from the electronic medical records. The association between the patient’s background and the cytogenetic data was analyzed using a Chi squared test. The average maternal age of the 132 cases of early spontaneous abortion was 34.2 ± 4.7 year (range: 24–43). Chromosomal abnormalities were detected in 89 cases (67.4%), among which 52.8% represented trisomy, 1.1% represented double trisomy, 10.1% represented polyploidy, 7.9% represented monosomy, 12.4% represented structural chromosomal abnormality, and 15.7% represented mosaic chromosome abnormalities. Women older than 35 year had a higher rate of chromosomal abnormalities than younger women (76.6% vs. 58.8%; P = 0.015). Twenty-five of the 132 pregnancies were achieved with ART and were associated with a higher rate of trisomy (64.0% vs. 37.4%; P = 0.008). G-banding identified a rare form of polyploidy 94,XXYYYY. Our results confirmed previous findings that older Japanese women with spontaneous miscarriages have a higher rate of chromosomal abnormalities.