Dual Trigger in IVF—A SWOT Analysis

The typical agent used for final oocyte maturation and resumption of meiosis in in-vitro fertilisation (IVF) has been human chorionic gonadotropin (hCG). This acts as a surrogate for the physiological spontaneous luteinising hormone (LH) surge. Gonadotropin-releasing hormone agonist (GnRH-a) has been used as an alternative trigger in cycles where endogenous LH control is achieved using GnRH-antagonist and has been shown to be an effective method of reducing the risk of OHSS. However, GnRHa trigger is associated with poor corpus luteum function, leading to impaired endometrial receptivity. A combination of a GnRHa and hCG (dual trigger) was proposed to improve IVF cycle outcomes, especially in poor and normo-responder patients. Dual trigger aims to provide a more physiological alternative to HCG-only trigger while obviating some of the problems associated with GnRHa alone. Clinical evidence now supports the value of dual trigger where there has been a previous low proportion of mature eggs or where there is a suboptimal LH response to GnRHa alone. In poor responders, dual triggers could be considered as an effective first line. Dual trigger allows for comparable outcomes in normal and high responders, allowing the possibility of fresh embryo transfer with good clinical pregnancy and live birth rates while minimising OHSS risk.