Comparison of a ‘freeze-all’ strategy including GnRH agonist trigger versus a ‘fresh transfer’ strategy including hCG trigger in assisted reproductive technology (ART): a study protocol for a randomised controlled trial

摘要

IntroductionPregnancy rates after frozen embryo transfer (FET) have improved in recent years and are now approaching or even exceeding those obtained after fresh embryo transfer. This is partly due to improved laboratory techniques, but may also be caused by a more physiological hormonal and endometrial environment in FET cycles. Furthermore, the risk of ovarian hyperstimulation syndrome is practically eliminated in segmentation cycles followed by FET and the use of natural cycles in FETs may be beneficial for the postimplantational conditions of fetal development. However, a freeze-all strategy is not yet implemented as standard care due to limitations of large randomised trials showing a benefit of such a strategy. Thus, there is a need to test the concept against standard care in a randomised controlled design. This study aims to compare ongoing pregnancy and live birth rates between a freeze-all strategy with gonadotropin-releasing hormone (GnRH) agonist triggering versus human chorionic gonadotropin (hCG) trigger and fresh embryo transfer in a multicentre randomised controlled trial.