Chromosome rearrangements among couples with pregnancy losses and other adverse reproductive outcomes.

During the years 1975-1987, 1,364 cytogenetic studies were performed in 682 couples with history of adverse pregnancy outcome. Thirty-six balanced translocations were detected, 24 (3.5%) in women and 12 (1.7%) in men. Before 1982, all 234 couples studied had 2 or more spontaneous abortions with unknown pedigrees, with an incidence of 6.8% of balanced translocations. During 1982-1987, complete pedigree analysis was performed on a subset of 448 couples, who were then classified into 3 groups. Group I; 321 couples with 2 or more spontaneous abortions, but no other adverse outcome; group II; 37 couples with at least one or more spontaneous abortions plus a malformed child or stillbirth; and group III; 90 couples with one or more spontaneous abortions plus a sib having at least a malformed child or repetitive spontaneous abortions. The incidence of balanced translocations in these 3 groups was 2.8%, 5.4%, and 10.0%, respectively. When group III was compared with group I, the frequency of translocations was significantly different (P less than 0.02). Robertsonian translocations were predominantly detected in women, raising the possibility that prezygotic failure producing primary sterility may occur in men with such translocations.