Postpartum depression begins when estrogen and progesterone fall sharply within hours to days after childbirth, destabilizing the brain's emotional regulation circuits. On top of this, the sleep deprivation from waking to nurse every night, the pressure of an unfamiliar parenting role, and the body's recovery process all overlap, producing symptoms such as persistent sadness, listlessness, guilt, poor concentration, and indifference toward the baby. It is common enough that 1 to 2 out of every 10 to 15 mothers experience it, and it happens not because of weak willpower but because of changes occurring in the body. Unlike the baby blues, which resolve on their own within two weeks of childbirth, postpartum depression lasts four weeks or longer and interferes with daily life.