Oocyte yield and dysmorphisms as indicators of biological efficiency in intracytoplasmic sperm injection cycles

The aim of the study was to examine whether oocyte yield could be an indicator of morphological oocyte quality and biological competency in patients younger than 36 years undergoing controlled ovarian stimulation (COS). Three hundred and thirty-five intracytoplasmic sperm injection (ICSI) procedures were arbitrarily subdivided into five groups according to the number of retrieved oocytes. Patients' demographic characteristics and treatment success were compared among the groups. The influence of the morphological oocyte abnormalities on outcomes was also investigated. The proportion of oocytes that gave rise to viable embryos and high-quality embryos decreased significantly according to oocyte yield. Similarly, the number of foetal heartbeat per retrieved oocyte in fresh embryo transfer cycles was higher in patients with fewer oocytes collected. Finally, a negative correlation was observed between the occurrence of intracytoplasmic oocyte dysmorphisms and the number of foetal heartbeat per oocyte. High oocyte yield may be considered an indicator of low oocyte biological efficiency and intracytoplasmic dysmorphisms may contribute to this biological wastage suggesting that protocols of minimal or mild stimulation should be used.