Granulocyte-macrophage colony-stimulating factor-containing medium for blastocyst recovery culture: study protocol for a randomized controlled trial (GSET-study).

BACKGROUND

Although the number of frozen-thawed blastocysts transfer is increasing worldwide, the live birth rate following blastocyst transfer using assisted reproductive technology remains at 30-60%. Thus, improving the pregnancy rate per transfer is an urgent issue. In a previous retrospective study, we evaluated the use of granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium for recovery culture to improve the outcomes of frozen-thawed blastocyst transfers. The results demonstrated that the live birth rates increased by approximately 10% following recovery culture in the GM-CSF-containing culture medium. This study aims to prospectively evaluate whether GM-CSF-containing blastocyst recovery culture following thawing increases live birth.

METHODS

This is a multicenter, randomized, parallel-group, active-controlled, single-blind trial. The recruitment target is 750 participants meeting the criteria. Enrolled patients are randomized 1:1 to the GM-CSF-containing culture medium group (test group) or the non-GM-CSF-containing culture medium group (control group). The blastocyst recovery culture after warming was defined as an intervention in this study; frozen-thawed blastocysts will be cultured for 3-7 h in GM-CSF-containing medium (test group) or medium without GM-CSF (control group) followed by blastocyst transfer. The primary outcome will be live birth. We will also evaluate embryo transfer outcomes as secondary efficacy endpoints and evaluate perinatal and neonatal outcomes as a safety endpoint.

DISCUSSION: This is the first large-scale prospective study to investigate the efficacy of a GM-CSF-containing medium for frozen-thawed blastocyst transfer. The study findings will provide evidence regarding the efficiency of GM-CSF-containing medium for blastocyst recovery culture after warming.

TRIAL REGISTRATION: Japan Registry of Clinical Trials jRCT1040240159. Registered on January 6, 2025.