It’s normal to see some fluctuation when you first start having periods and again as you approach menopause. But if you notice changes in your period along the way, it could be because of an underlying cause that needs immediate attention. A heavier flow one month is often not a cause for concern. But if you experience a noticeable increase in your flow over a few months or have ongoing irregular periods, you should see your doctor to check for an underlying cause. Fibroids, infection, sexually transmitted diseases, thyroid problems, cancer and endometrial polyps are some conditions that can cause heavier bleeding.