I am currently 25,non sexually active female, I used to have moderate to heavy periods accompanied with heavy abdomen pain which lasted for 4-5 days. Since a couple of months, my periods have reduced to 3 days, they are still regular but lighter and I experience just back pain. The only changes I have done to my lifestyle since over last year, I eat vitamin B tablets daily and Vitamin D tablets once a week. I follow moderate vegetarian nutrition. My concern is should I be worried about this shorter cycles.