Intracytoplasmic sperm injection: optical magnification for sperm selection and microinjection affects fertilization, cleavage and pregnancy rates. Fertility & Sterility, vol. 80, Suppl. 3, pág. 124, September 2003. Trabalho apresentado no 59º Congre

P-10 Intracytoplasmic sperm injection: Optical magnification during sperm selection and microinjection affects fertilization, cleavage, and pregnancy rates. Sandro C. Esteves, A R. Guidi, S. F. C. Zabaglia, S. Verza Jr.

ANDROFERT-Centro de Refereˆncia em Infertilidade Masculina, Campinas, Brazil.

Objective: To evaluate the effect of performing ICSI using two different optical magnification on fertilization, cleavage, and pregnancy rates.

Design: A prospective and randomized clinical study.

Materials and Methods: This study included 120 ICSI cycles from September 2002 to February 2003. Cycles were divided in two groups: group 1 (n _ 60): sperm selection and microinjection were performed using 200X magnification, and group 2 (n _ 60): sperm selection and microinjection using 400X magnification. All injections were performed by one person. In group 1, all injections were performed with the polar body at 6 or 7 o _ clock position. In group 2, 82% of the injections were performed with the polar body at 6 or 7 o _ clock position while the remaining were done with the PB in different positions because it was suspected, by morphological appearance, that the injection at 6 or 7 o _ clock position could damage the MII meiotic spindle. Female age, mean number of oocytes retrieved and mean number of MII oocytes were not statistically different in groups 1 and 2.

Results: Significantly more oocytes developed two pronuclei in group 2 than in group 1 (74.1 _ 23.8 versus 57.4 _ 30.2, P _ 0.001). Significantly more good quality embryos developed in group 2 than in group 1 either on day 2 (65.4 _ 37.4 versus 44.2 _ 37.8, P _ 0.002) and day 3 (54.6 _ 34.9 versus 27.8 _ 28.3 (P _ 0.001). The percentage of abnormally fertilized oocytes was higher in group 1 (11.4 _ 17.5 versus 1.4 _ 4.7, P _ 0.0001). Higher pregnancy rate (P _ 0.046) was found after transfer of embryos derived from group 2 (38.8%) versus group 1 (24.9%).

Conclusion: Given the better results with 400X magnification, it is recommended that spermatozoa be selected and oocytes be injected with the higher magnification as possible, to optimize the chance of selecting the best morphologically normal sperm and to minimize the chance of damaging the MII meiotic spindle.