Low-level sex chromosome mosaicism in female partners of couples undergoing ICSI therapy does not significantly affect treatment outcome

BACKGROUND: There is an increased rate of chromosomal anomalies, in particu lar low-level sex chromosome mosaicism, in the female partners of couples u ndergoing intracytoplasmic sperm injection (ICSI). METHODS: Among 811 conse cutive couples presenting for pre-ICSI chromosome analysis, chromosomal abn ormalities were detected in 54 individuals, of which 26 were low-level sex chromosome mosaicism in the females. Attention was focused on the treatment course and outcome of ICSI in 20 couples with low-level sex chromosome mos aicism in the females actually embarking on ICSI treatment (group I, n = 38 ICSI treatment cycles). Applying a case-control design, each of the 20 cou ples was matched according to female age and source of spermatozoa to coupl es without a chromosomal abnormality in either of the partners (group II, n = 38 ICSI treatment cycles). RESULTS: No significant differences were foun d between the groups in ovarian response, fertilization rate and number of embryos transferred. Pregnancy rates, as well as implantation and abortion rates did not differ significantly between the groups. CONCLUSIONS: The dat a suggest that low-level sex chromosome mosaicism in females has no major e ffect on the course and outcome of ICSI.