Intracytoplasmic sperm injection could minimize the incidence of prematurely condensed human sperm chromosomes.

OBJECTIVE

To compare the fertilization and prematurely condensed human sperm chromosomes (PCCs) rates between two intracytoplasmic sperm injection (ICSI) techniques.

DESIGN

A retrospective study.

SETTING

The data were obtained from the University of British Columbia in vitro fertilization (IVF) laboratory.

PATIENT(S): ICSI cycles (n = 105) were performed for couples suffering from severe male-factor infertility and dysfunction of fertilization.

INTERVENTION(S): Two types of ICSI techniques were used for ICSI procedures.

MAIN OUTCOME MEASURE(S): Fertilization and pregnancy rates in group B using the improved ICSI technique were compared with those of group A using the standard ICSI technique. Unfertilized oocytes from the two groups were studied with cytogenetic methods.

RESULT(S): Oocyte damage dropped from 14.8% in group A to 5.3% in group B. Normal fertilization for each group was 57.3% and 88.4%, respectively (P<.05). Pregnancy rate per egg retrieval was 15.6% in group A and 27.4% in group B (P<.05). PCCs occurred in 19.4% of unfertilized oocytes in group A and did not occur in group B.

CONCLUSION(S): This study indicates that ICSI not only yields high fertilization rates, but also minimizes the incidence of PCCs. It may be directly related to two crucial steps (immobilization of sperm and aspiration of oocyte cytoplasm) used in ICSI procedures. This study also suggests that it is possible to overcome one cause of IVF failure resulting from the formation of PCCs by using the improved ICSI technique.