Menopause is a normal biological process that affects females at some point in their lives. When natural, it often sets in during their early 50s, but it can occur up to a decade earlier. It marks the end of their natural reproductive years  and officially declares itself when their menstruation permanently ends. Menopause happens because the ovaries stop producing estrogen and other sex hormones.
Most people understand menopause to be the end of a female’s menstruation. This isn’t the full picture. Menopause doesn’t happen all at once. There are distinct stages that build up into the process. There is a transition period referred to as perimenopause. Not all females as experience this, however. This may be due to factors that cause menopause to set in suddenly, such as cancer therapy or surgical removal of the uterus or ovaries. Menopause is confirmed when there has been no menstrual flow for up to 12 months.
Premenopause vs. Perimenopause
Premenopause and perimenopause can sound like the same thing and are often used interchangeably in some spaces, but they don’t always describe the same thing. Premenopause is not a scientifically recognized term , so you won’t really find healthcare professionals using it. Still, it’s a common term and, depending on who is using it, what it means might be a little unclear.
Premenopause literally means “before menopause”. Usually, this describes the period of time before menopause when your menstrual flow still occurs. It begins at puberty and continues through a female’s fertile years. During this period, you have no symptoms of menopause yet and menstruation is normal. Hormonal changes may happen at this time but they aren’t noticeable. Some people use this term to describe perimenopause. It is more useful to think of premenopause as the normal reproductive years before perimenopause .
Perimenopause is used to describe the time around the onset of menopause. This is known as the transition period. By this time, the symptoms of menopause have begun to manifest in your body but menopause has not officially set in yet.