Automatic user-independent zona pellucida imaging at the oocyte stage allows for the prediction of preimplantation development

ObjectiveTo analyze whether a change in three-dimensional structure of the zona pellucida could indicate suboptimal gamete quality.DesignProspective study.SettingWomen's general hospital.Patient(s)A total of 72 patients who gave informed consent.Intervention(s)The birefringence of all oocytes was prospectively analyzed with an automatic user-independent polarization microscopy imaging system.Main Outcome Measure(s)Birefringence of the inner zona layer, preimplantation development, implantation, and pregnancy.Result(s)In approximately one third of all gametes (244/712), the system's automatic detection of the inner zona layer did not succeed. This phenomenon was a negative predictor of compaction (P < 0.01), blastulation (P < 0.001), and pregnancy (P < 0.001). In cases of successful zona imaging, the score based on the birefringence of the inner zona layer was a strong predictor of blastocyst formation but not of embryo quality or pregnancy (P > 0.05). Interestingly, antagonist protocol resulted in lower zona scores as compared with the long protocol (P < 0.05).Conclusion(s)Combining the information from both undetected and detected oocytes, zona imaging was a helpful tool in oocyte selection. This knowledge might further help to reduce both the time in culture and the number of concepti considered for transfer.