Minor chromosomal variants and major chromosomal anomalies in couples with recurrent abortion.

One hundred three women with prior histories of recurrent spontaneous abortion and 81 of their mates were karyotyped with Q-banding during 1976-1980. Recurrent abortion was defined as two or more spontaneous pregnancy losses; no couple with a previous malformed fetus or child was included. These cases were reviewed in order to examine the possible contributions of minor polymorphic chromosomal variants and major chromosomal abnormalities to recurrent spontaneous pregnancy loss. Balanced translocations were detected in four women and two men in the study; mosaic X aneuploidy was noted in one woman. Quantitative (1 qh, 9qh, 16qh, Yqh) and qualitative (3c, 4c, 13p, 13s, 14p, 14s, 15p, 15s, 21p, 21s, 22p, 22s) heterochromatic polymorphisms were blindly assessed and compared with a control group. Cases and controls did not differ in the frequency of any qualitative polymorphisms or in the length of any quantitative polymorphism. Thus, while major parental cytogenetic aberrations are significantly associated with fetal wastage, these data suggest that minor polymorphic chromosomal variants do not play an important role in the etiology of recurrent spontaneous abortion.