All girls and women have very different menstrual cycles. Some have very heavy ones, some have painful ones, some have light ones, etc. Although many times different doesn't mean abnormal, changing a tampon more than once an hour is excessive.
Two main things affect menstrual periods: hormones and anatomy. The ovaries usually handle the hormone part. They send signals each month to the uterine lining so that it knows to grow or shed (menses) each month. The hormones have to occur in specific ratios in order for the menstrual cycle to be regular and for ovulation to occur (unless, of course, the birth control pill or some other form of contraception is preventing ovulation). The anatomy part of it means that every female's uterus is different. Some causes of heavy or irregular bleeding are structures called fibroids (benign smooth muscle tissue bundles in the uterine wall or in the uterine cavity) or polyps (benign tissue inside the uterine cavity.)
You may need medication (i.e. birth control pills) to control a hormonal cause or even a procedure (and sometimes surgery) if there's a structural reason for your abnormal bleeding.
Dr. Kathleen Sullivan Schiavi is an OB/GYN at East Jefferson General Hospital. To make an appointment with Dr. Schiavi or another physician at EJGH, please call HealthFinder at 504-456-5000.