Association between the number of oocytes and cumulative live birth rate: A systematic review

The available literature is controversial regarding the association between the number of oocytes retrieved and the cumulative live birth rate (CLBR). Although some authors report a continuous increase in the CLBR with the number of oocytes retrieved, others have found a plateau. A systematic review was conducted, including all eligible studies published until June 2022, to determine the optimal number of oocytes retrieved to maximize the CLBR. We found a positive association between the number of oocytes and the CLBR. However, this association varies according to patients' age. While in patients younger than 35 years, little benefit is derived from increasing the number of oocytes above 25-30, in patients older than 35 years, the number of oocytes seems to improve the CLBR until the extreme of reproductive age is reached. In women aged 44 years or older, the CLBR will be consistently low, independent of the number of oocytes retrieved.