EC Gynaecology

Endometrial preparation is crucial in IVF protocols to create optimal conditions for embryo implantation and pregnancy. Successful embryo nidation requires a receptive endometrium, influenced by factors such as endometrial thickness, hormonal environment, autocrine and paracrine growth factors, and resident stem cells in the endometrium basalis. Synchronization between embryonic and endometrial development is essential. However, identifying the precise Window of Implantation (WOI) is challenging due to variability in estrogen and progesterone production, metabolism, and metabolic clearance rates (MCR). This review aims to outline a clinical approach that, though not absolute, assists in understanding complementary phenomena and provides useful guidance for practice.

 Keywords: Endometrium; Basalis; Functionalis; Estradiol; Progesterone; Metabolic Clearance Rate; Transport; Growth Factors; Endometrial Thickness; Markers of Decidualization; Pinopodes; Endometrial Assessment; Embryo Implantation

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