X chromosome aneuploidy in lymphocyte cultures from women with recurrent spontaneous abortions.

Occasional metaphases with X chromosome aneuploidy can be detected in short-term lymphocyte cultures from women with recurrent abortions. The significance of this finding is unknown. It has been suggested that it may reflect a genetic tendency to nondisjunction that predisposes these women to an increased risk of producing aneuploid offspring. We have investigated prospectively the frequency of X chromosome aneuploidy in lymphocyte cultures from 104 women with a normal chromosome constitution and a history of recurrent pregnancy loss defined as 2 or more spontaneous abortions. Seventeen women (16%) had a significant number (2-10%) of X aneuploid cells in cultured lymphocytes but no evidence of constitutional chromosome mosaicism, based on analysis of fibroblast cultures. A control group of age-matched fertile women without a history of recurrent abortions showed a similar level of X chromosome aneuploidy in lymphocyte cultures. No increased risk for production of liveborn children with aneuploidy was found on retrospective analysis of the reproductive histories of these women. A significant effect of culture conditions on X chromosome gain or loss has been demonstrated by comparison of medium 199 with Dulbecco's modified Eagle medium.