Sperm deposition site during ICSI affects fertilization and development.
OBJECTIVE
To evaluate the effects of sperm placement during ICSI relative to the M-II spindle location on fertilization and preimplantation development.


METHODS
Retrospective analysis of oocyte fertilization and embryo development with respect to sperm deposition site during ICSI.


METHODS
A program of IVF-ET.


METHODS
Seven hundred seventy-six patients.


METHODS
Egg quality, sperm deposition site, and polar-body position were recorded during ICSI; fertilization was assessed on day 1; embryo development was evaluated on days 2 and 3.


METHODS
Fertilization, embryo development, and implantation rates.


RESULTS
Normal fertilization is not affected by polar-body orientation, with the exception of a significantly lower fertilization rate from a 9 o'clock polar-body orientation. Injections with the polar-body positioned at 7 or 11 o'clock result in the greatest number of high-quality embryos, significantly more than the adjacent 6 or 12 o'clock polar-body orientations and irrespective of oocyte anomaly frequency. Embryos originating from the 7 or 11 o'clock polar-body category implant at a higher rate, although the data are not significant.


CONCLUSIONS
The placement of the sperm during ICSI relative to the presumed location of the meiotic spindle significantly impacts fertilization and high-quality embryo development. Sperm deposition in the M-II spindle area should be avoided. It appears that development, and not fertilization, is improved by decreasing the distance between the sperm cell and the spindle.
Blake
M
M
The Institute for Reproductive Medicine and Science of Saint Barnabas, West Orange, New Jersey, USA. MarlenaBlake@embryos.net
Garrisi
J
J
Tomkin
G
G
Cohen
J
J
D002467:Cell Nucleus / Q000648:ultrastructure; D010064:Embryo Implantation; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009865:Oocytes / Q000648:ultrastructure*; D015388:Organelles / Q000648:ultrastructure; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D016896:Treatment Outcome