Human steroidogenesis: implications for controlled ovarian stimulation with exogenous gonadotropins

Area of Science:

• Reproductive endocrinology
• Steroidogenesis
• Ovarian physiology

Background:

• The menstrual cycle involves gonadotropin surges (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) initiating the periovulatory interval.
• Controlled ovarian stimulation (COS) utilizes gonadotropins, leading to supraphysiological steroid concentrations distinct from natural cycles.
• Elevated progesterone during COS may cause endometrial alterations, potentially affecting oocyte viability and reproductive outcomes in assisted reproductive technology due to asynchrony between embryo and endometrium.

Purpose of the Study:

• To review current knowledge on progesterone regulation in the human ovary during the follicular phase.
• To highlight existing gaps in understanding the hormonal regulation of progesterone production during COS.
• To provide detailed information on the regulation and function of gonadotropins in steroidogenesis.

Main Methods:

• Literature review of current scientific evidence.
• Analysis of hormonal systems regulating progesterone production in the human ovary.
• Examination of the interplay between theca and granulosa cells, LH, and FSH actions.

Main Results:

• Progesterone regulation during COS involves complex interactions between hormonal systems, theca and granulosa cells, and gonadotropin actions.
• Supraphysiological steroid profiles in COS differ significantly from natural cycles.
• The impact of elevated progesterone levels on fertility outcomes in COS remains uncertain.

Conclusions:

• The precise role of elevated progesterone in COS on fertility is not definitively established.
• Further research is needed to clarify the detrimental effects, if any, of high progesterone levels on reproductive outcomes in assisted reproductive technology.
• Understanding gonadotropin regulation of steroidogenesis is crucial for optimizing COS protocols.