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It’s a common scene in any ob-gyn practice: A patient comes in, concerned that her periods have changed. “What’s going on?” she asks. “Is this menopause?”

If you’re a woman in your 40s, a change in your menstrual periods is the hallmark of perimenopause – that’s what we call the years leading up to your last menstrual period. 

Here’s a look at how we diagnose perimenopause and menopause, and what else to expect as you enter this phase of life.

A new normal

A “change” can mean a lot of things when it comes to your menstrual period. It could be a change in the length of your cycle. It could mean your period is coming more often or less often. The flow could be heavier or lighter than you’re used to. You also could have some bleeding or spotting between periods.

No matter the symptoms, women can usually recognize what’s normal for them – and when that stops being the norm. Your ob-gyn is there to help you figure out what’s going on.

Other explanations

Perimenopause is what we call a diagnosis of exclusion. This means we first need to rule out other conditions that could be causing your abnormal bleeding. Other causes can include:

  • Hormonal problems, such as a thyroid disorder or hyperprolactinemia (high levels of the hormone prolactin)

  • Problems with the uterus, such as polyps, fibroids, or adenomyosis (a problem with the lining of the uterus)

  • Infection

We use a combination of pelvic exams, blood tests, and ultrasounds to guide this framework. If nothing is wrong, then perimenopause is the likely explanation of irregular periods, especially for a woman in her 40s.

The course of perimenopause

A change in your periods is often the first sign of perimenopause, but there are other signs to look out for. The most common are hot flashes, sleep problems, vaginal dryness, mood changes, and a decrease in sex drive. Not every woman will experience all of these symptoms. For those who have symptoms, they may come in any order.

Once these symptoms arrive, most women can expect menopause itself to be a few years away. (Menopause is officially confirmed after you go 12 months without a menstrual period. But the average age for the last period is 51.)

There are many treatments to help with bothersome symptoms like hot flashes and sleeplessness. Even a few years of hormone therapy can help you get through the worst of it.  

If you are prone to anxiety or depression, know that perimenopause can bring those conditions back to the surface. Finding a support network can make a big difference. Antidepressants also may be an option.

Part of the reproductive journey

We usually diagnose menopause in hindsight, after that full year of absent periods. I’ve found that most women know they’ve reached menopause when they get there.

Even if your irregular periods turn out to be something else, you’ll face menopause eventually. Talk with your ob-gyn about what you’re experiencing. Together we can work through this part of your health journey.


The views expressed in this article are those of Dr. Eisenberg and do not reflect the views of the National Institutes of Health, the Department of Health and Human Services, or the United States government.

Published: October 2020

Last reviewed: September 2022

Copyright 2023 by the American College of Obstetricians and Gynecologists. All rights reserved. Read copyright and permissions information.

This information is designed as an educational aid for the public. It offers current information and opinions related to women's health. It is not intended as a statement of the standard of care. It does not explain all of the proper treatments or methods of care. It is not a substitute for the advice of a physician. Read ACOG’s complete disclaimer.

About the Author
Esther Eisenberg, MD, MPH
Dr. Esther Eisenberg

Dr. Eisenberg is an obstetrician–gynecologist and reproductive endocrinologist. She serves as medical officer in the Fertility and Infertility Branch at the National Institute of Child Health and Human Development. Her areas of expertise include reproductive aging, infertility, polycystic ovary syndrome, and endometriosis. She is a fellow of the American College of Obstetricians and Gynecologists.