Dear Ma'am, Slight changes in menstrual cycle with age are considered normal, especially a slight reduction of flow. If you do not have excessive pain, have regular cycles and do not have difficulty in conceiving, all you should do is wait and maintain a menstrual diary. If any other complications occur or you have a difficulty in conceiving then you may consider a gynaecological consult to rule out thyroid disorders,  hyperprolacteinemia and pcos. Regards, Aditi