Prediction of the rates of fertilization, cleavage, and pregnancy success by cumulus-coronal morphology in an in vitro fertilization program.

OBJECTIVE: To examine the relation between the grading of cumulus-coronal morphology at oocyte retrieval and the rates of fertilization, cleavage, and pregnancy success in IVF-ET cycles. DESIGN: Retrospective study. SETTING: University-affiliated medical center. PATIENT(S): Infertile women who underwent IVF-ET treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Fertilization and cleavage of the oocytes and the pregnancy outcome. RESULT(S): Mature grade 3 cumulus-oocyte complexes (COCs) constituted the highest percentage among all grades and had a higher fertilization rate than COCs of other grades (77% versus 65%, 43%, and 28% for grades 2, 1, and 4, respectively). The cleavage and polyspermy rates did not correlate with cumulus-coronal morphology grading. The pregnancy rate was higher in cycles with >50% grade 3 COCs than in cycles with < or =50% grade 3 COCs (32% versus 16%). In cycles with >80% grade 3 COCs, the pregnancy rate was 57%. The correlation between the percentage of grade 3 COCs and the pregnancy rate was independent of patient age and the number of COCs retrieved. CONCLUSION(S): The cumulus-coronal morphology grade correlates with the fertilization rate but not with the cleavage or polyspermy rate. In vitro fertilization cycles that have a greater percentage of grade 3 COCs have an increased chance of resulting in pregnancy. The cumulus-coronal morphology grade predicts pregnancy success in IVF-ET cycles.