The postpartum period, also known as the puerperium, lasts around 6 weeks as the body returns to its pre-pregnant state. During this time, the uterus involutes from 1000g back to 60g, the cervix narrows, and the vagina regains tone. Lochia is discharged for 1-3 weeks as the endometrium regenerates. Physiological changes include temperature regulation returning to normal and increased risk of urinary tract issues as the bladder adapts. Nursing care focuses on monitoring involution and managing any complications.