Review question / Objective: This systematic review aims to evaluate the efficacy of progestin-primed ovarian stimulation (PPOS) on reproductive outcomes in patients with polycystic ovary syndrome (PCOS) undergoing assisted reproductive techniques. Condition being studied: PCOS is a common endocrine disorder that can cause infertility in women of childbearing age. The PPOS protocol, which involves oral progestins with gonadotropin (Gn), has been shown to be effective and safe in treating patients with PCOS. However, the question of whether PPOS provides a significant benefit over conventional GnRH analogue protocols in PCOS patients is still controversial.