Second polar body extrusion is highly predictive for oocyte fertilization as soon as 3 hr after intracytoplasmic sperm injection (ICSI).

OBJECTIVE

Our objective was to evaluate the time course and the predictive value of the extrusion of the second polar body after intracytoplasmic injection (ICSI) related to the fertilization rate, embryo cleavage and quality.

SETTING

The setting was the in vitro fertilization program of a university hospital.

PATIENTS

Twenty-one patients were treated with intracytoplasmic single sperm injection either for fertilization failure in IVF, low fertilization in IVF (< 5%), or severe male factors.

DESIGN

One hundred thirty-five of 205 metaphase 2 oocytes treated with intracytoplasmic single sperm injection were observed 1, 2, and 3 hr after the assisted fertilization procedure. Extrusion of the second polar body was recorded. For each of these oocytes, fertilization was noted 18 hr after ICSI and cleavage and embryo quality were assessed 24 hr later. The 70 remaining oocytes were used to assess a possible negative effect of repeated exposure to light microscopy.

RESULTS

The extrusion of the second polar body 3 hr after injection was an observation with a sensitivity of 0.87, a specificity of 0.58, and a high positive predictive value (0.90) toward oocyte fertilization. Twenty-nine and four-tenths percent of the oocytes extruded a second polar body within the first hour, 56.6% within the first 2 hr, and 78.3% had a second polar body 3 hr after injection. This time course was related neither to the speed of embryo cleavage nor to the embryo quality. Fertilization, cleavage, and embryo quality were not affected by repeated observation as deduced from comparison with the control group and confirmed by a high pregnancy (62% per oocyte retrieval) and implantation rate (22% per replaced embryo).

CONCLUSION

Oocytes can be checked, in all safety, 3 hr after a single sperm injection for the presence of a second polar to predict oocyte fertilization with a high certainty.