The uterus is an organ of the female reproductive system. Its main function is to house and nourish a fetus until it’s ready for birth. The uterus sits in the middle of the pelvis, behind the bladder and in front of the rectum. The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. The fertilized ovum divides to become a blastocyst, which implants into the endometrium. The fertilized ovum becomes an embryo and attaches to a wall of the uterus, creates a placenta and develops into a fetus until childbirth.