The Influence of Seasons on Oocyte Parameters in ICSI Cycles

Objective: This study aimed to evaluate the effect of seasonal variability on the assisted reproductive technique (ART) success rate. Materials and methods: This study was a descriptive – analytical survey performed on 91 infertile women undergoing intracytoplasmic sperm injection – embryo transfer (ICSI-ET) in different seasons. The patients aged less than 35 years old and had normal LH/FSH ratio. All patients entered long protocol down regulation treatment cycle and the picked up oocytes were transferred to GIII medium in the infertility laboratory. The cumulus characteristics, oocyte parameters including number of the retrieved oocytes, morphological characteristics, fertilization and degeneration rate and number of cleaved embryos were recorded. Data were analyzed by SPSS software. Results: The number of embryos was significantly higher in autumn. Abnormal morphological parameters (color, size, zona thickness) and the degeneration rate were significantly higher in spring. The number of retrieved oocytes, MI, MII oocytes and fertilization rate had no significant seasonal variations. Conclusion: The results of this study showed a significant seasonal variation in morphological parameters of the oocytes, degeneration rate and the number of formed embryos.