What age does perimenopause start?

Part 2 of 5: Perimenopause Awareness Month Series

How do you know when perimenopause has started? 

You can’t always know for sure when perimenopause has started, especially in the early stages. However, changes to your menstrual cycle can be one of the first signs of perimenopause. 

You might notice: 

• Periods become less predictable after being fairly regular

• Periods become heavier or last longer

• Your cycles become shorter, with less time between periods

How long does perimenopause last? 

For some people, perimenopause can last just a few years. For others, it can last longer than 10 years. There’s no way to know exactly how long it will last for you. 

However, some people experience other symptoms, such as hot flashes, sleep changes, or mood changes, before they notice significant changes to their cycle. 

How do I know what stage of perimenopause I’m in?

Perimenopause is divided into two stages: early perimenopause and late perimenopause. 

What age does early perimenopause start?

Early perimenopause typically starts when someone is in their mid-40s, but it can also start earlier or later. 

In early perimenopause, the length of your menstrual cycles may begin to vary by around seven days or more. This variation often increases as you move through perimenopause. The length of this stage varies from person to person and may last between 1 and 8 years.

These cycle changes are caused by changing levels of hormones, particularly estrogen and progesterone. During this time, you may notice that your period arrives earlier or later each cycle than expected. It may also be lighter or heavier, or last for a shorter time than before.  

What about late perimenopause? 

In late perimenopause, menopause may be around one to three years away.  During this stage, you may go 60 days or longer without a period. As ovulation becomes less frequent, your period might go away for months at a time and then return.

Eventually, you’ll have your final period. Menopause is confirmed once you’ve gone 12 consecutive months without a period, as long as there isn’t another reason for your periods to have stopped. 

Pregnancy is still possible during perimenopause, even if your periods are irregular or you go several months without one. For some people, periods may stop more abruptly, with only a short period of noticeable cycle changes beforehand.

How will I know I’m in perimenopause?

Perimenopause is a natural stage of life rather than an illness. That means it can’t technically be diagnosed.

However, you and your healthcare provider can work together to determine whether the changes you’re experiencing are likely to be related to perimenopause.

There’s no single definitive way to tell with absolute certainty that you’re in perimenopause, especially early on. Tracking changes to your menstrual cycle and any related experiences can help provide useful clues. 

Perimenopause experiences vary widely. For some people, symptoms become more frequent or noticeable as they get closer to menopause. As cycle changes become more pronounced, it may become easier to recognize that you're in the transition.

What hormone tests can be done for perimenopause?

Hormone testing usually can’t confirm whether you’re in perimenopause or determine what stage you might be in. This is because hormone levels—including estrogen and follicle-stimulating hormone (FSH)—can fluctuate considerably during this time.

A single test may therefore provide only a snapshot and can’t reliably show where you are in the transition.

For most people over 45, healthcare providers assess perimenopause based on age, changes to menstrual patterns, and symptoms rather than hormone tests. Testing may sometimes be helpful if symptoms begin at a younger age, periods have stopped unexpectedly, or a healthcare provider wants to investigate another possible cause. Menopause is usually confirmed retrospectively after 12 consecutive months without a period, rather than through hormone testing.  

Up next → Part 3: What perimenopause actually feels like—typical experiences & what to expect.