MICROSATELLITE MUTATIONS IN SPONTANEOUSLY ABORTED EMBRYOS

Objective: To evaluate the incidence of microsatellite instability in spontaneously aborted embryos. Design: Retrospective study. Setting: L aboratory of Clinical Virology and Department of Obstetrics and Gyneco logy, University Hospital, Medical School, University of Crate. Patien t(s): Thirty-live women in whom spontaneous abortions occurred between the 6th and 20th weeks of pregnancy. Intervention(s): Thirty-five abo rted embryonic tissues were analyzed with seven microsatellite markers , and their haplotypes were compared with the corresponding pattern of their parents. Main Outcome Measure(s): Microsatellite DNA. Result(s) : Microsatellite instability was observed in 8 of 35 cases (23%). In 7 of 8 positive cases, microsatellite instability was restricted to one of the seven microsatellite markers, whereas in one case, three micro satellite markers Mere affected by instability. A statistically signif icant association was found between microsatellite instability and a p revious normal childbirth. Conclusion(s): Genetic instability is a det ectable phenomenon in spontaneous abortions, representing a significan t increase in the mutational rate of the embryo and providing evidence for a mechanism associated with the phenomenon of spontaneous abortio n. We conclude that this elevated mutational rate affects active genom ic sequences that play a critical role in the viability of the embryo, leading to cell death and abortion. (Fertil Steril(R) 1998.70:892-5, (C) 1998 by American Society for Reproductive Medicine.).