Tissue sampling technique affects accuracy of karyotype from missed abortions

Purpose: To determine if careful specimen selection and washing of tissue from first trimester missed abortion products of conception specimens increases the sensitivity of routine cytogenetics in detecting aneuploidy. Methods: Retrospective review of cytogenetics results from tissue from dilation and curettage for missed abortion in a university fertility practice between 1998 and 2001. A technique of careful selection and washing of the specimen was implemented in July 1999. Results from before (n = 15) and after (n = 41) this change were compared. Cytogenetics reports from other physicians using the same laboratory were used for comparison (n = 59). Results: The percentage of 46XX results was significantly decreased in the test group when compared to historical and community controls: 29% vs. 73% and 56% respectively. The percentage of aneuploid results was significantly higher in the test group at 61% vs. 7% and 36% in the historical and community controls respectively. Conclusion: Thorough separation and cleaning of villi prior to sending missed abortion specimens significantly increases sensitivity of conventional cytogenetics for detecting aneuploidy by decreasing maternal contamination.