Perimenopause in Your 40s: What Changes Are Common?

Perimenopause is the stretch of years before menopause, when the ovaries gradually make less estrogen and progesterone (NICHD). Most people begin the menopausal transition between ages 45 and 55, and it may last for several years (NIA). That timing means perimenopause often overlaps with a person's 40s.

This guide summarizes what public health sources and research describe about this stage. It's general information, not a way to assess any individual's health.

When perimenopause usually starts and how long it lasts

Most people reach menopause between ages 45 and 55, and the average age is 51 (NICHD). People who smoke may reach menopause earlier than people who don't (NICHD).

The menopausal transition comes first and may last for several years. Symptoms related to menopause can last between two and eight years, and timing varies widely (NIA). Menopause is the point when a person has gone 12 months in a row without a period (NICHD).

Changes in periods

According to The Menopause Society, people reaching perimenopause may notice changes in how often their periods come and how heavy they are. Over time, cycle length may vary by 7 days or more, and later in the transition some people go 60 days or more between periods (The Menopause Society). MedlinePlus describes periods coming less often over time and eventually stopping. For most people this happens gradually, though for some it happens suddenly (MedlinePlus).

Other changes people commonly report

Hot flashes and night sweats are the most commonly reported symptoms of the menopause transition (The Menopause Society). MedlinePlus also lists these among common symptoms of the menopause transition (MedlinePlus):

• Night sweats
• Sleep problems
• Mood changes
• Vaginal dryness

Research suggests these changes can last for years. In the Study of Women's Health Across the Nation (SWAN), 1,449 women reported frequent hot flashes or night sweats, and the median length of time those symptoms lasted was 7.4 years (Avis et al., JAMA Internal Medicine, 2015).

Not everyone experiences every change, and how noticeable the changes are varies widely from person to person.

When to see a clinician

Questions about perimenopause, or about any change in health, are best discussed with a licensed clinician who knows a person's history. In a medical emergency, call 911 or go to the nearest emergency room.

Frequently asked questions

How is perimenopause different from menopause? Perimenopause is the transition leading up to menopause. Menopause is the point when a person has gone 12 months in a row without a period (NICHD).

Can perimenopause start at 40? Timing varies widely. According to the National Institute on Aging, most people begin the menopausal transition between ages 45 and 55 (NIA), and menopause occurs earlier for some (NICHD).

How long do hot flashes last? It varies. In the SWAN study, women with frequent hot flashes or night sweats had them for a median of 7.4 years (Avis et al., 2015).

Does smoking affect when menopause happens? According to NICHD, people who smoke may reach menopause earlier than people who don't (NICHD).