Is it normal to cramp on and off a few days before your period is expected? also my periods have been getting lighter in flow. whats the cuase?

To the degree that estrogen/progesterone fluctuate toward the end of a given cycle, "cramps" are a common occurrence. Lighter flow of bleeding during menstrual events may occur occasionally. A gauge of normal hormonal production is the regularity of menstruation, with periods occurring every 24-32 days apart, some cycles are heavier than others.