Question#5

Author: Prof: Claus Y. Andersen

Introduction

For more than two decades, frozen–thawed ovarian cortex transplantation has been performed to restore fertility. It is well established that a substantial proportion of transplanted follicles fail to survive during the first one to two weeks after grafting, leaving only a limited fraction available for long-term endocrine function and fertility.

Despite the widespread use of the technique, there is no consensus on the optimal method of transplantation. Approaches vary considerably between centres: in some, cortical fragments are assembled in the laboratory to form a coherent graft, which is then placed onto the decorticated ovary; in others, the fragments are threaded onto a string to stabilize them within a peritoneal pocket. In certain settings, cortical fragments are sutured into small pockets either in the ovary or peritoneal wall; elsewhere, they are placed beneath a tissue flap to prevent displacement without suturing. Additional centres use fibrin-based or other bio-adhesive materials to temporarily secure the graft.

A more standardised approach to transplantation would clearly be desirable, but defining appropriate endpoints is challenging. Pregnancy following transplantation of frozen–thawed tissue is the ultimate goal, yet patients may keep tissue frozen for years before undergoing transplantation. Furthermore, pregnancy may occur several years after the procedure (with reports of pregnancies even five years post-transplantation), meaning that outcomes initially considered failures may later prove successful.

Scientific Question

The ultimate objective of ovarian cortex transplantation is to restore fertility, resulting in pregnancies and the birth of healthy children. While overall success rates across larger patient series appear broadly comparable, the variability in transplantation techniques raises an important question: do methodological differences influence outcomes such as graft function, longevity, or fertility? The growing number of procedures worldwide now provides a unique opportunity to compare outcomes systematically across centres and techniques.

Study Design

This collaborative study aims to evaluate outcomes following different transplantation techniques. Proposed endpoints include:

• Ovarian activity: AMH levels measured at defined intervals after transplantation (e.g., 6 months, 1 year), compared with pre-treatment AMH levels where available.

• Graft longevity: Duration of endocrine activity, assessed by the length of time the woman resumes and maintains menstrual cycles (approximating the fraction of ovary restored).

• Reproductive outcomes: Number of pregnancies achieved, with live births as the primary outcome, supplemented by detailed documentation of pregnancy losses.

• Transplantation site: Outcomes in relation to anatomical location, e.g., in situ placement on the postmenopausal ovary versus peritoneal pockets.

Collaborative Potential

Within the ISFP network, participating centres could contribute outcome data according to their standard transplantation technique. Such collaboration would provide valuable comparative insights and help define best practices for one of the most critical procedures in fertility preservation.

Get in contact with as us by writing to info@isfp-fertility.org