Hi...., If she is Pregnant then there would be missing of periods. Instead of irregular periods..... In a normal menstrual cycle, a balance between the hormones estrogen and progesterone regulates the buildup of the lining of the uterus (endometrium), which is shed during menstruation. If a hormone imbalance occurs, mentrual irregularities occurs.....Consult your Gynecologist for further advice.....