Luteal Phase Defects (LPD), also known as Corpus Luteum Insufficiency or Luteal Phase Insufficiency, are characterized by insufficient function of the corpus luteum, resulting in inadequate progesterone secretion. This can lead to a shortened luteal phase and poor endometrial secretion, which are critical for embryo implantation and pregnancy maintenance. During the menstrual cycle, women with LPD still experience normal follicular development and ovulation. However, due to early degeneration of the corpus luteum or insufficient progesterone, the luteal phase becomes dysfunctional. This can hinder the thickening of the endometrium, which is necessary for a fertilized egg to implant. Luteal Phase Defects are a common cause of female endocrine dysfunctions, impacting fertility and pregnancy outcomes. With advancements in Assisted Reproductive Technology (ART), LPD has become more prevalent, particularly among ART patients. The condition is often addressed through progesterone supplementation or other fertility treatments to improve the luteal phase function and enhance chances of conception. Management of LPD typically includes hormone therapy to correct progesterone deficiency and optimize the uterine environment for implantation.