Illustration of the female reproductive system. The uterus is a hollow, muscular organ where a fertilised egg implants and develops into a foetus during pregnancy. The lining of the uterus sheds during menstruation if pregnancy does not occur. The ovaries are located on either side of the uterus. They produce eggs and secrete hormones, such as oestrogen and progesterone. The fallopian tubes are responsible for transporting eggs from the ovaries to the uterus. The cervix is the lower part of the uterus that connects to the vagina. The vagina, which is a muscular canal, extends from the cervix to the external genitalia. It serves as a passageway for menstrual fluid, receives the penis during sexual intercourse, and acts as a birth canal during childbirth.