G.Schwanitz2, P.Albers3, G.Haidl4 and

5To whom correspondence should be addressed This paper reports on results of intracytoplasmic sperm injection (ICSI) in patients in whom constitutional or secondary chromosome aberrations were detected in the male and/or female partner. Out of 434 couples treated by ICSI (590 cycles), 16 couples (3.7%) were affected by constitutional chromosome aberrations and 96 (22.1%) by secondary chromosome aberrations. Constitutional chromosome aberrations were found in eight male and eight female patients. Couples with the aberration in the male showed significantly lower fertilization, implantation and pregnancy rates (P < 0.05). The occurrence of female constitutional chromosome aberrations led to lower fertilization rates but implantation and pregnancy rates were similar to a control group; however, a higher abortion rate was noted. In the group with secondary chromosome aberrations, 22 males and 59 females carried an abnor-mality and in 15 couples, both partners. Compared to the remaining (unaffected) 322 couples, fertilization and embryo transfer rates were reduced but implantation rates and pregnancy rates were not different. In all couples where an abortion occurred, mainly parental autosomal aberrations were involved (six out of eight). Our retrospect-ive analysis shows that an unexpectedly high number of infertile couples in an ICSI programme are affected by chromosome aberrations, which in turn may explain the reduced fertilization rates observed in this subgroup of patients. Key words: constitutional chromosome aberrations/genetic risk/ intracytoplasmic sperm injection/secondary chromosome aber-ration