Perimenopause is the transitional phase leading up to menopause, marking the end of a woman's reproductive years. It typically begins in a woman's 40s but can start earlier. During this time, hormone levels fluctuate, causing changes in menstrual cycles, mood swings, and physical symptoms like hot flashes. This phase can last several years, with varying experiences for each woman. Some may notice irregular periods, while others might have heavier or lighter flows. Understanding perimenopause can help women prepare for the changes ahead and seek support if needed.