The myometrium is the middle layer of the uterus, composed of smooth muscle tissue. It plays a crucial role during childbirth by contracting to help push the baby out of the womb. These contractions are regulated by hormones, particularly oxytocin. In addition to its role in labor, the myometrium also supports the endometrium, the inner lining of the uterus, and helps maintain the overall structure of the uterus. Its ability to expand and contract is essential for various reproductive functions, including menstruation and pregnancy.