In the years before menopause officially happens—which is defined as when the last period stops—a host of other symptoms can arise for many women. These symptoms are caused by shifting hormones but can feel very uncomfortable and even frightening. The most common symptoms, according to Stephanie Goodwin, M.D.,a menopause specialist based in London, are mood changes, such as symptoms of depression and anxiety. But there are many others.

In fact, there are 39 other symptoms also associated with this seismic shift in the body, according to Goodwin, who walks us through the most common of them here and explains perimenopause, as well as how a woman can identify where she is in the process.