Perimenopause: Everything You Need to Know

Every woman faces perimenopause at some point in her life. This is the transition phase between having normal menstrual cycles and going through menopause (the menstrual cycle’s end). It occurs when the levels of cycle-regulating hormones change.

A woman's body gradually lessens its production of important hormones, like estrogen and progesterone, during this time - though the amounts of estrogen often go up and down erratically. The ovaries slow down their egg production, leading to women becoming less fertile.

This process typically takes around four years. For some women, it can take considerably longer. Other women experience this phase in less time. Generally speaking, perimenopause can last from several months to 10 years.

At What Age Does Perimenopause Start?

Each woman's body is unique. Some women begin menopause in their 40s while others begin in their 50s. According to the North American Menopause Society, the average age for the onset of menopause is 51.

Since perimenopause precedes menopause and usually lasts around four years, that means most women enter perimenopause around age 47. However, since bodies change at different rates, it's not uncommon for women in their early 40s or even late 30s to enter the transition phase of perimenopause.

Early Perimenopause

For women who begin menopause early, perimenopause also occurs before it should. Doctors generally consider perimenopause premature if it occurs when a woman is in her early to mid-30s.

There are several factors that contribute to early perimenopause. One is genetics. Scientists believe that the age at which menopause starts is passed down. Chromosome defects that cause ovarian issues, such as Turner syndrome, can be to blame.

Another factor is a person's lifestyle. Heavy smokers tend to enter perimenopause before women who don't smoke. Having an extremely low body mass index can affect estrogen stores, leading to early onset as well.

Diseases can cause this too. Treatments for cancer, like chemotherapy, sometimes damage the ovaries or halt the production of estrogen. The inflammation caused by autoimmune disorders can damage a woman's ovaries and trigger perimenopause to begin.

When Does Perimenopause End?

Perimenopause ends when menopause begins. This is determined by the date of the last period you have.

As perimenopause gets closer to ending, estrogen levels drop faster. It’s not uncommon to go more than six months without a period during this time. Doctors declare that you have officially entered menopause when it’s been more than 12 months since you’ve gone through your monthly cycle.

Tests for Perimenopause

The simplest way to determine if you're in perimenopause is to ask your mother or grandmother when she began the transition. Since there's a genetic component to when menopause starts, your mother's onset date is a good indication of when yours will be.

Of course, not everyone has that option. Another way to determine it is by monitoring your menstrual cycle. If your period comes earlier or later by around a week on a consistent basis, you might be in the beginning stages of perimenopause. However, you should speak to a doctor about changes in your period to rule out other issues.

Because perimenopause is a slow transition that can take years, there's not a single test that can conclusively diagnose it. Your doctor will look at your medical history and your age to make a determination. They may check your hormone levels and your thyroid as well.