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

Introduction Pregnancy 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. Methods and analysis Multicentre randomised, controlled, double-blinded trial of women undergoing assisted reproductive technology treatment including 424 normo-ovulatory women aged 18-39 years from Denmark and Sweden. Participants will be randomised (1:1) to either (1) GnRH agonist trigger and single vitrified-warmed blastocyst transfer in a subsequent hCG triggered natural menstrual cycle or (2) hCG trigger and single blastocyst transfer in the fresh (stimulated) cycle. The primary endpoint is to compare ongoing pregnancy rates per randomised patient in the two treatment groups after the first single blastocyst transfer. Ethics and dissemination The study will be performed in accordance with the ethical principles in the Helsinki Declaration. The study is approved by the Scientific Ethical Committees in Denmark and Sweden. The results of the study will be publically disseminated. Trial registration number NCT02746562; Pre-results

HCG Trigger After Failed GnRH Agonist Trigger Resulted in Two Consecutive Live Births:A Case Report

Background: Failed gonadotropin-releasing hormone (GnRH) agonist trigger with no oocyte retrieved during aspiration of several follicles is a rare but recurrent situation that can be rescued by the termination of the aspiration procedure, retriggering by human chorion gonadotropin (hCG), and repeated oocyte pickup 36 h later. Failed GnRH agonist trigger is frustrating and unsatisfactory, and fertility doctors must be aware of possible hCG retriggering and retained opportunity for successful cycle outcome. Objective: In this case report, we present a woman who experienced failed GnRH agonist trigger and rescue hCG retrigger followed by two consecutive live births after frozen-thawed single blastocyst transfers. Methods: A case report. Results: Two healthy children were born in 2018 and 2020, respectively as a result of controlled ovarian stimulation for IVF, failed GnRH agonist trigger followed by hCG re-trigger, and successful retrieval of 25 oocytes. Conclusion: Retriggering with hCG after failed GnRH agonist trigger can result in consecutive live births, and such knowledge can prevent cycle cancellation and patient discouragement. Knowledge on retriggering with hCG and consecutive live births after failed GnRH agonist trigger can prevent cycle cancellation and patient discouragement