Cytogenetic analysis of the retained products of conception after missed abortion following blastocyst transfer: a retrospective, large-scale, single-centre study

Cytogenetic analysis of the retained products of conception (POC) is the most effective test for identifying miscarriage causes. However, there has been no large-scale study limited to blastocyst transfer. This study retrospectively reports the findings of 1030 cases in which POC analysis was performed after missed abortion following single blastocyst transfer performed at the Shinbashi Yume Clinic. We identified 19.4% as normal karyotypes and 80.6% as aneuploid. These cases broke down into: 62.3% trisomy; 7.8% double trisomy; 0.5% triple or quadruple trisomy; 1.3% monosomy 21; 3.2% monosomy X; 0.1% 47,XXY; 1.0% polyploidy; 1.0% mixed; 1.1% embryonic mosaicism; and 2.4% structural anomalies. In samples with normal karyotypes, 49.5% were female while 50.5% were male. The occurrence of trisomy and double trisomy were both significantly more frequent in the ≥38 years group than in the ≤37 years group (P < 0.01). Trisomy was significantly more frequently associated with fetal heartbeat (P < 0.01); double trisomy, polyploidy and normal karyotype were significantly more frequent with no fetal heartbeat (P < 0.01). There was no significant difference in the frequency of chromosomal abnormalities between the number of miscarriages or blastocyst quality. Thus, POC cytogenetic testing is highly valuable for ascertaining the cause of miscarriage.