In vitro growth of secondary follicles from cryopreserved-thawed ovarian cortex.

Study Question: Can secondary follicles be obtained from cultured cryopreserved-thawed human ovarian cortical tissue?

Summary Answer: We obtained high-quality secondary follicles from cultured cryopreserved-thawed human ovarian cortical tissue from cis female donors (cOVA), but not from trans masculine donors (tOVA) in the same culture conditions.

What Is Known Already: The in vitro growth of oocytes present in unilaminar follicles into metaphase II stage (MII) oocytes has been previously achieved starting from freshly obtained ovarian cortical tissue from adult cis female donors. This involved a multi-step culture protocol and the first step included the transition from unilaminar follicles to multilayered secondary follicles.

Cumulative live birth rate of a blastocyst versus cleavage stage embryo transfer policy during in vitro fertilisation in women with a good prognosis: multicentre randomised controlled trial.

Objectives: To evaluate whether embryo transfers at blastocyst stage improve the cumulative live birth rate after oocyte retrieval, including both fresh and frozen-thawed transfers, and whether the risk of obstetric and perinatal complications is increased compared with cleavage stage embryo transfers during in vitro fertilisation (IVF) treatment.

Design: Multicentre randomised controlled trial.

Setting: 21 hospitals and clinics in the Netherlands, 18 August 2018 to 17 December 2021.

Classification of Atretic Small Antral Follicles in the Human Ovary.

The reproductive lifespan in humans is regulated by a delicate cyclical balance between follicular recruitment and atresia in the ovary. The majority of the small antral follicles present in the ovary are progressively lost through atresia without reaching dominance, but this process remains largely underexplored. In our study, we investigated the characteristics of atretic small antral follicles and proposed a classification system based on molecular changes observed in granulosa cells, theca cells, and extracellular matrix deposition.

Dynamic culture of cryopreserved-thawed human ovarian cortical tissue using a microfluidics platform does not improve early folliculogenesis.

Current strategies for fertility preservation include the cryopreservation of embryos, mature oocytes or ovarian cortical tissue for autologous transplantation. However, not all patients that could benefit from fertility preservation can use the currently available technology. In this regard, obtaining functional mature oocytes from ovarian cortical tissue would represent a major breakthrough in fertility preservation as well as in human medically assisted reproduction.

Single-Cell Transcriptomics Analysis of Human Small Antral Follicles.

Human ovarian folliculogenesis is a highly regulated and complex process. Characterization of follicular cell signatures during this dynamic process is important to understand follicle fate (to grow, become dominant, or undergo atresia). The transcriptional signature of human oocytes and granulosa cells (GCs) in early-growing and ovulatory follicles have been previously described; however, that of oocytes with surrounding GCs in small antral follicles have not been studied yet.