Defining the terms

Perimenopause is the transition period leading up to menopause — when your reproductive hormone levels begin to decline.

Perimenopause typically starts in your mid-to-late 40s, but the timing varies. Some women experience symptoms in their 30s or early 40s. Perimenopause lasts, on average, about 4 years. But it can continue for up to a decade. You've officially reached menopause once you've gone a full year without a menstrual period.

During perimenopause, estrogen levels drop and you may notice more irregularity in your periods. That’s a sign you’re getting closer to menopause.

Menopause is a natural part of life. Menopause isn’t just the end of your period. It’s a major hormonal shift that affects almost every part of your body — from your brain and bones to your sleep, mood, and metabolism.

You’ve officially hit menopause when you haven’t had a menstrual period for 12 straight months. This typically happens between 45 and 56.

Reaching menopause before 45 is called early menopause. Premature menopause happens at 40 or younger.

Menopause is a specific point in time after perimenopause. Once you reach menopause, you’re in postmenopause — which lasts for the rest of your life.

Estrogen is one of the primary female sex hormones, and it serves an important function in both reproductive and overall health. Estrogen supports many important processes, from the development of secondary sex characteristics (like breast growth) to regulating your menstrual cycle. It plays an essential role in ovulation, pregnancy, and vaginal lubrication. Estrogen also has a variety of non-reproductive functions. It can impact your mood, bone health, brain function, weight, and even the condition of your skin and hair.

By the time you reach menopause, your body will have gradually stopped producing estrogen the way it used to.

The transition to menopause, known as perimenopause, can unfold over the course of several years. It’s common for estrogen levels to rise and fall unpredictably during this time. While menstrual cycles, ovulation, and pregnancy can still occur, estrogen levels will gradually decline.

Once you reach menopause — officially defined as going 12 months without a menstrual period — ovulation ends and estrogen levels drop permanently. At this time, the primary form of estrogen in your body switches from estradiol (E2) to estrone (E1).

Progesterone plays a key role in reproductive and hormonal health. Here’s how:

As you enter perimenopause and approach menopause, progesterone levels drop — often faster than estrogen.

This hormonal shift can cause symptoms like:

Read more about progesterone.

Estradiol is a type of estrogen, which is a group of sex hormones made by both male and female bodies.  It helps regulate your menstrual cycle. 

Estrogen levels (including estradiol) drop during menopause, which can cause symptoms like hot flashes, mood swings, and trouble sleeping.

Learn more about estradiol.

Low estrogen is a hormonal imbalance that most commonly occurs during perimenopause and menopause — a natural life stage when the body begins producing less estrogen. This shift can often bring a wave of new (and sometimes frustrating) emotional and physical symptoms.

Low estrogen is a natural part of the transition into menopause, when estrogen production declines significantly. Once women reach menopause — defined by 12 months of amenorrhea, or the absence of menstrual periods — estrogen levels remain consistently low.

Hot flashes are one of the most frequent and disruptive vasomotor symptoms associated with the menopausal transition. They involve a sudden wave of heat, usually beginning in the face, neck, or chest, that may spread throughout the body.

Episodes can last from a few seconds to several minutes, and often bring flushing, sweating, a racing heartbeat, and sometimes a sense of anxiety or unease. As the body cools, many women experience chills or shivering.

When hot flashes happen at night, they’re called night sweats. These can disrupt sleep, leading to fatigue, difficulty concentrating, and reduced quality of life. While some women only have occasional, mild episodes, others experience frequent and intense hot flashes that interfere with daily activities and emotional well-being.

Perimenopause is the transitional phase leading up to menopause when hormone levels begin to fluctuate and decline and menstrual cycles become irregular.

Perimenopause often begins in your 40s but can start as early as the mid-30s. Every person’s timeline is different.

On average, perimenopause lasts 4–6 years before menopause.

The earliest signs of perimenopause often include irregular periods, hot flashes, mood swings, sleep disruptions, and changes in menstrual flow.

Common symptoms of perimenopause include night sweats, brain fog, vaginal dryness, decreased fertility, and weight changes, in addition to irregular cycles.

Yes. Ovulation can still occur during perimenopause, even with irregular cycles, so pregnancy is still possible. Birth control may be needed until menopause is reached, so we encourage you to consult with your women’s health or primary care provider.

While there isn’t a single test to determine or diagnose perimenopause, certain lab tests may provide helpful insights. However, a healthcare provider should review your symptom severity and medical history to see if treatment is right for you.

Light spotting during perimenopause, even just when wiping, can be common due to hormonal fluctuations. However, heavy bleeding or unusual patterns should always be checked by a provider.

Weight gain isn’t caused by perimenopause alone, but hormonal changes can shift fat storage, especially around the belly. Aging, metabolism, and lifestyle also play a role.

Perimenopause is the lead-up to menopause. Menopause is a point in time that’s reached once you’ve gone 12 consecutive months without a period.

Insurance isn’t required, so there are no complicated insurance questions or health insurance plan considerations.