Abnormal embryogenesis in the etiology of ectopic pregnancy

Flow cytometric measurements of DNA using paraffin-embedded retrospective material were performed on 42 samples of ectopic conceptuses to see whether there were any aberrations from normal DNA. It was found that DNA aneuploidy was associated with tubal implantation in 14 (33%) cases. The range of DNA indices of the DNA aneuploid peaks was from 1.14 to 2.17. Near-diploid karyotype changes were seen in 8 (19%) cases. Six cases were found to be tetraploid. In 18 abortions with known cytogenetic status, all 3 cytogenetically normal cases showed DNA diploidy in flow cytometry. It was also found that 3 out of 10 cases of trisomy 21 were DNA aneuploid. Flow cytometric DNA reflects only chromosomal changes where a significant number of cells have either lost or acquired several chromosomes. DNA aneuploidy of ectopic pregnancies suggests a grave chromosomal aberration in one third of the cases. Abnormal embryogenesis may contribute significantly to the occurrence of ectopic implantation.