"The prevalence of chromosome abnormalities in women facing a single sporadic miscarriage is to be 45%. Approximately 50% to 60% of early spontaneous miscarriages are associated with a chromosomal anomaly of conceptus. Most common abnormality is aneuploidy, with autosomal trisomy accounting for more than 50% of chromosomally abnormal abortuses. A strong family history of recurrent miscarriage or genetic anomaly suggests a parental karyotypic abnormality, and a chromosomal analysis of the affected partner is appropriate in the primary evaluation. Chromosomal analysis of the miscarriage offers an explanation in at least 50% of cases. Parental karyotyping is not predictive of a subsequent miscarriage. Routine karyotyping of couples with recurrent miscarriage is not recommended. Cytogenetic analysis may be performed on products of conception to avoid unnecessary evaluation and treatment and because an aneuploid conceptus indicates a somewhat greater likelihood of success with a subsequent pregnancy (Evidence Level III)."