Spectrophotometric analysis of follicular fluid related to oocyte fertilization, embryo cleavage, and follicular fluid protein and hormone content.

Spectrophotometric absorbance patterns of follicular fluids (FF) obtained from in vitro fertilization patients were analyzed and compared with oocyte fertilization and embryo cleavage rates. Each absorbance pattern was resolved into three components: delta OD360, delta OD415, and delta OD455. A positive correlation was found between fertilization outcome and delta OD455. The absorbances were not related to embryo cleavage rates. We confirmed the presence of bilirubin and beta-carotene in FF: these pigments absorb at 455 nm and are most likely serum-derived. To explain the association between delta OD455 and fertilization, we hypothesized that the FF delta OD455 is a marker of the degree of vascularization of the follicle that could be assessed by FF protein and hormone concentrations. However, no correlation was found between the delta OD455 and these FF parameters, suggesting an alternative explanation for this association.