Aromatase activity in granulosa cells as a predictor of pregnancy potential

The ability to predict the potential of an oocyte to sustain embryo development in vitro would be an advantageous tool for reproductive technology. Currently, the only measure of oocyte quality is based on cumulus expansion or nuclear maturation. Neither of these observations predicts the degree of cytoplasmic maturation, which is critical for normal embryo development. The unique cell-to-cell interaction between the oocyte and surrounding granulosa cells (GCs) provides an opportunity to measure oocyte competence by quantifying properties of the supporting GCs. We have observed that the capability of GCs to synthesize estrogen, as measured by aromatase activity (AA), is related to pregnancy success of patients being treated for infertility. Evaluation of AA may provide a reliable non-invasive method of predicting implantation potential of embryos.