A. Menstrual flow can be quite variable in girls, especially the first year that it starts. It is very common for girls to have a few cycles and then none for a month or two, and then start again. Eventually, most girls settle into a pattern of having their periods about every 28 to 35 days. The flow can last 3 to 7 days. There are some days, usually the first two days, when the flow is heavy, and other days when it is very light.
Most young girls start out wearing pads because they are easy to use.
A pad should be changed every three or four hours, and possibly more often on days when the flow is heavy. The other reason to change them often is that an odor can develop over time. For some girls who have a small vaginal opening, it may be difficult and uncomfortable to insert a tampon. For these girls, it's probably a good idea to wait until they've matured a bit more and the vaginal opening has stretched out. A girl also needs to be mature enough to feel comfortable inserting a tampon into the vagina.