X-chromosome inactivation and ovarian age during the reproductive years

ObjectiveTo explore whether skewed X-chromosome inactivation (XCI) is related to indicators of ovarian age.DesignThe XCI skewing percent and indicators of ovarian age were measured in women with recent pregnancy losses and women with recent livebirths. All analyses adjust for chronologic age and pregnancy outcome.SettingHospital in eastern central New York.Patient(s)One hundred thirty-six women with informative XCI assays: 83 with index pregnancy losses and 53 with livebirths.Intervention(s)None.Main Outcome Measure(s)The primary indicators of ovarian age were antral follicle count, levels of FSH and inhibin B. A secondary indicator was level of estradiol (E2).Result(s)The XCI skewing percent, defined either continuously or categorically (≥90%), was unrelated to the indicators of ovarian age. The sample was large enough to rule out as unlikely a modest decline in antral follicle count or a modest increase in FSH in relation to skewed XCI.Conclusion(s)X-chromosome anomalies are associated with skewed XCI and with premature ovarian failure. Our data raise the possibility that X-chromosome anomalies may not be an important influence on ovarian aging in menstruating women.