[CHALLENGING THE OPTIMAL NUMBER OF RETRIEVED OOCYTES AND ITS IMPACT ON PREGNANCY AND LIVE BIRTH RATES IN IVF/ICSI CYCLES].

INTRODUCTION: Large numbers of retrieved oocytes are associated with higher chances of having cryopreservation of embryos. However, the process entailed exposes women to increased risk for ovarian hyperstimulation syndrome. Furthermore, mild ovary stimulation protocols are more patient-friendly and with less adverse effects. Only limited reports exist on the significance of the number of retrieved oocytes achieved in a single stimulation cycle. AIM: To investigate the optimal number of retrieved oocytes to achieve pregnancy and live birth. METHODS: This retrospective analysis included 1590 IVF cycles. Oocytes maturation, fertilization, cleavage, as well as pregnancy and live birth rates were analyzed according to the number of retrieved oocytes. RESULTS: Oocyte maturation, fertilization and cleavage rates were lower in cycles with more than 10 retrieved oocytes compared with other groups. Live birth rates were highest when the number of retrieved oocytes was 11-15. CONCLUSIONS: Retrieval of more than 15 oocytes was not associated with a significant increase in chances of conception and birth. DISCUSSION: The better oocyte quality with 10 or less oocytes retrieved could be the result of a possible interference with the natural selection, or the minimized exposure of growing follicles to the potentially negative effects of ovarian stimulation. Although the average number of available embryos was higher when more than 10 oocytes were retrieved, achievement of more than 15 oocytes did not improve IVF outcome in terms of pregnancy and delivery rates. SUMMARY: Analysis of 1590 IVF cycles including the frozen-thawed transfers shows that the best outcomes were achieved with an optimal number of 11-15 oocytes.