Vaginal itching before menstrual cycle - I am experiencing vaginal itching and irregular menstrual periods. See a gynecologist. It's a good idea for you to see a gynecologist to discuss these issues. What Causes Itchy Vagina Before Period? If you are experiencing a continuous vaginal itching before period, Irregular Periods and Pregnancy;. It is not uncommon to experience vaginal itching around the time of menstruation. There are several causes for this: vaginal dryness, yeast infection or simply hormonal changes.