Skewed sex ratio and low aneuploidy in recurrent early missed abortion.

BACKGROUND AND OBJECTIVES: Conventional cytogenetic studies have revealed more number of females in spontaneous abortion and it has been assumed that a large proportion of those were resulted from maternal contamination and overgrowth of maternal decidua in long term culture. In this study we have attempted to overcome difficulties of conventional cytogenetics by using meticulous tissue dissection and molecular methods onto uncultured chorionic villous tissue thus bypassing long term culture to find out true sex ratio and frequency as well as type of common aneuploidy in early missed abortions. METHODS: Early missed abortion products (n=58) were collected from recurrent aborter in and around Lucknow, India, over a period of three years. All the cases were selected on the basis of ultrasonography diagnosis. Chorionic villous tissue was cleaned from maternal tissue and processed for conventional as well as molecular cytogenetic analysis. RESULTS: Conventional cytogenetics was successful in 15, of which 12 were females and 3 males. There were 3 cases of chromosomal abnormality, including one false. Interphase FISH with X, Y, 1, 9, 12, 16, 18 and 13/21 probes was carried out in all 58 cases. There were 43 females and 15 males. Four cases of chromosomal abnormality were detected by interphase FISH (6.9%). Comparative genomic hybridization was successful in 8 cases (6 females and 2 males). There was no aneuploidy; however, suspected gain and losses were seen in 4 cases. INTERPRETATION AND CONCLUSION: Our results suggested skewing of sex ratio (M : F, 1 : 2.9 ) and low aneuploidy rate, indicating that in early missed abortion from recurrent spontaneous abortion female outnumbers male. The various possibilities with literature support are presented that may serve as a template for future work.