A reappraisal of ovarian stimulation strategies used in assisted reproductive technology

AbstractOvarian stimulation is a fundamental step in assisted reproductive technology (ART) with the intention of inducing ovarian follicle development prior to timed intercourse or intra-uterine insemination and facilitating the retrieval of multiple oocytes during a single in vitro fertilization (IVF) cycle. The basis of ovarian stimulation includes the administration of exogenous gonadotropins, with or without pre-treatment with oral hormonal therapy. Gonadotropin-releasing hormone agonist or antagonist is given in addition to the gonadotropins to prevent a premature rise of endogenous luteinizing hormone that would in turn lead to premature ovulation. With the advancement in technology, various stimulation protocols have been devised to cater for different patient needs. However, ovarian hyperstimulation syndrome and its serious complications may occur following ovarian stimulation. It is also evident that suboptimal ovarian stimulation strategies may have a negative impact on oogenesis, embryo quality, endometrial receptivity, and reproductive outcomes over recent years. This review describes the various forms of pre-treatment for ovarian stimulation and stimulation protocols, and aims to provide clinicians with the latest available evidence.Keywords: Duostimgonadotropin-releasing hormone agonist protocolgonadotropin-releasing hormone antagonist protocolovarian stimulationprogestin primed ovarian stimulation AcknowledgmentsWe would like to thank Ms Wing Iu Li (research nurse) and Elaine Yee Lee Ng (research assistant) for their support and assistance in preparing this review.Disclosure statementNo potential conflict of interest was reported by the author(s).Data Availability StatementThis review article is based on a comprehensive analysis and synthesis of existing published literature. All the data used in this review are publicly available through the cited references. No additional datasets were generated or analysed specifically for this review. Readers are encouraged to refer to the cited sources for further information and access to the original data.