Perimenopause
The transitional period before menopause, during which a woman's body undergoes various changes as it approaches the end of reproductive years. This phase can last several years and is characterized by fluctuations in hormone levels, particularly estrogen and progesterone, leading to symptoms such as irregular menstrual cycles, hot flashes, and mood swings. Perimenopause typically begins in a woman's 40s but can start as early as the mid-30s, affecting women who are approaching menopause.