Frequency and patterns of premature sperm chromosome condensation in oocytes failing to fertilize after intracytoplasmic sperm injection.
OBJECTIVE
The purpose of this study was to evaluate reasons for fertilization failure after intracytoplasmic sperm injection as a part of internal quality control and to review corresponding previous data.


METHODS
One hundred injected but unfertilized oocytes were fixed and examined after Giemsa staining.


RESULTS
Three oocytes (3.0%) did not show the presence of a spermatozoon and two (2.0%) contained pronuclear structures. An intact spermatozoon was found in 25 cases (25.0%), whereas the sperm nucleus had undergone premature chromosome condensation (PCC) in 70 cells (70.0%). A modified classification system was established to characterize the different PCC patterns.


CONCLUSIONS
PCC indicates a correct intracytoplasmic injection and excludes technical problems as a major reason for fertilization failure in the present study. A lack of oocyte activation due to cytoplasmic immaturity is considered responsible for the occurrence of PCC. A review of the literature shows that the role of sperm chromatin abnormalities in the process of nuclear decondensation needs further investigation.
Rosenbusch
B E
BE
Department of Gynecology and Obstetrics, University of Ulm, Donau, Germany.
D000328:Adult; D002467:Cell Nucleus / Q000473:pathology; D002843:Chromatin / Q000378:metabolism; D002869:Chromosome Aberrations; D005260:Female; D005306:Fertilization; D006651:Histocytochemistry; D006801:Humans; D007246:Infertility / Q000209:etiology / Q000473:pathology*; D008297:Male; D009865:Oocytes / Q000502:physiology*; D011786:Quality Control; D020554:Sperm Injections, Intracytoplasmic / Q000592:standards; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology*
D002843:Chromatin