The uterus is a pear-shaped, hollow, and muscular organ located in the female pelvis between the bladder and rectum. It is a reproductive organ that plays a critical role in menstruation, fertility, and pregnancy. The uterus has several functions, including:

• Menstruation: The uterus is the site of menstruation, a 28-day hormone-controlled cycle in which the uterine lining proliferates to prepare for the implantation of a fertilized ovum and subsequently sheds if fertilization does not occur.

• Pregnancy: The uterus stretches to grow the baby during pregnancy and contracts to help push the baby out of the vagina during delivery.

• Fertility: The uterus is where a fertilized egg implants during conception and where the baby grows.

The uterus consists of three layers: the perimetrium, the outermost protective layer; the myometrium, the highly muscular middle layer; and the endometrium, the innermost layer that lines the uterus and changes in thickness during the menstrual cycle. The uterus is supported by the pelvic floor muscles, perineal body, and ligaments in the pelvis, lower back, and hips.