This prospective observational study will include women undergoing IVF treatment with a GnRH antagonist protocol and fresh embryo transfer at the IVF unit of Shaare Zedek Medical Center. Patients will undergo controlled ovarian stimulation followed by ovulation triggering with hCG, GnRH agonist, or dual trigger according to OHSS risk. After oocyte retrieval and fertilization by IVF/ICSI, embryos will be cultured and transferred. Luteal phase support will consist of either intranasal GnRH agonist (Synarel) or vaginal progesterone. Blood and follicular fluid samples will be collected at predefined time points to assess hormonal, inflammatory, and angiogenic markers, including LH, FSH, estradiol, progesterone, IL-6, IL-8, VEGF, PEDF, and relaxin.