Perimenopause vs. Menopause: What’s the Difference?

Most women have a baseline understanding of menopause—namely that you’ll stop getting a period and may have other symptoms along with it. But perimenopause is a little mysterious, largely because its symptoms are more vague.

Women also may not be expecting perimenopause when it happens. Some recent research suggests that women may go through perimenopause earlier than doctors previously thought. The study, which was published in the journal NJP Women’s Health, analyzed symptoms reported from more than 4,400 women who were 30 and older. Researchers discovered that 55.4% of women who were 30 to 35 had symptoms that could be considered “moderate” or “severe,” based on the Menopause Rating Scale (MRS), a questionnaire that analyzes the severity of menopause symptoms. Those symptoms included mental health complications like anxiety, depression and irritability, along with sexual health issues, bladder problems and vaginal issues. 

But a whopping 64.3% of women who were 36 to 40 also had “moderate” or “severe” symptoms. Despite this, the researchers found that most women don’t talk to their doctor about symptoms of menopause or perimenopause until they’re at least 56. 

Based on the findings, the researchers concluded that “a significant number of individuals aged 30–45 years experience perimenopause-related symptoms.” There are a bunch of caveats with this study, including the fact that plenty of symptoms of perimenopause can overlap with health conditions that have nothing to do with the life stage. Meaning, women can have anxiety, depression or sexual health issues at any age—not just during perimenopause. 

So how do you even know you’re in perimenopause? What’s the difference between perimenopause and menopause? Flow Space tapped three OB-GYNs to learn more. 

What Is Perimenopause?

Perimenopause is defined as the years leading up to menopause, according to the American College of Obstetricians and Gynecologists (ACOG). It usually happens during your later 30s and 40s.

“Your hormones are declining and also fluctuating as they start to decline,” says Dr. Jessica Shepherd, OB-GYN, chief medical officer at Hers author of Generation M: Living Well in Perimenopause and Menopause. “This creates symptoms that will many times intensify in menopause but will appear sporadically over time.” 

Changes in your menstrual periods are typically a sign perimenopause is starting. While most women in perimenopause still get their period, although it may be irregular, says Dr. Lauren Streicher, an OB-GYN and clinical professor of obstetrics and gynecology at Northwestern University’s Feinberg School of Medicine. This is due to changes in levels of the hormone estrogen, which helps control your cycle. 

Your period’s flow could become lighter or heavier than usual, and you may start to skip periods, she says.

“Not only are your estrogen levels irregular, but you may get surges,” Streicher explains. “It can be a very challenging time, because you don’t know what to expect.”

How Is Perimenopause Different than Menopause?

While perimenopause can feel similar in some ways to menopause, it’s different. “Perimenopause is the transitional phase leading up to menopause and can begin several years before a woman’s final menstrual period,” explains Dr. Maral Malekzadeh, a board certified OB-GYN and co-owner of The Well Westlake. “Menopause is a defined clinical point and is diagnosed after 12 consecutive months without a menstrual period.”

Menopause is when you naturally stop having periods, marking the end of your reproductive years, according to ACOG. Your ovaries also stop making estrogen. Every woman is different, but the average age for menopause is 51, per ACOG.  

You’re considered to be in menopause when you’ve gone 12 months without any periods or spotting. When this happens, you’ve transitioned from perimenopause to menopause.

“It also has symptoms that will appear in addition to the cessation in bleeding, such as hot flashes, night sweats, sleep disturbances and many more,” Shepherd says. 

It’s also important to know that the way a woman experiences perimenopause doesn’t necessarily dictate how she’ll experience menopause. Just because you experienced intense mood swings, for example, doesn’t mean you’ll also have them in menopause.

“In perimenopause, symptoms such as hot flashes, sleep disruption and mood changes are often intermittent and unpredictable due to fluctuating hormone levels,” explains Malekzadeh. “As a woman transitions into menopause, those symptoms may become more consistent as hormone levels stabilize at a lower baseline.”

She adds that some symptoms can evolve as a woman transitions from perimenopause to menopause. For example, hot flashes might become more noticeable and intense in menopause whereas they were less so in perimenopause. This is why it’s especially important to continually monitor symptoms so treatments can be adjusted if warranted.

How Can You Tell Which Phase You’re in?

When deciding whether someone is in perimenopause or menopause should be clearcut in theory, “changing or unpredictable cycles suggest perimenopause, while the complete absence of periods for a full year confirms menopause,” says Malekzadeh.

However, this can be a little harder to tell in practice. “It would be nice if there was an alert on your phone or something, but there’s not,” Streicher says. “Women are told that they’re post-menopausal when they stop having periods, but a significant number of women don’t have periods, whether from continuous birth control, an IUD or something else.”

There is a blood test that your doctor can do to look at your estrogen levels, but Streicher says that can be “misleading” and confusing because it only looks at one moment in time.

“You may get an estrogen level that’s normal, and the doctor will say, ‘You’re not in perimenopause.’ But it could have been taken during a phase when your estrogen was high,” she says. 

Because hormones levels can shift quickly, Streicher and Malekzadeh say the best way to pinpoint whether someone is in perimenopause is by looking at both cycle history and symptoms.

“In perimenopause, the most common feature is changes in the cycle,” explains Streicher. “It may be irregular or get heavier or lighter.” But you may also notice things like hot flashes, night sweats, mood swings, sleep issues, vaginal dryness and changes in your sex drive, Streicher says. 

You can experience those symptoms in menopause, too—you just won’t have a period along with them. 

When to See a Doctor About Perimenopause

If you’re in your late 30s or solidly in your 40s, it’s a good idea to check in with your healthcare provider about perimenopause during your next wellness visit. But, if you’re dealing with symptoms that are bothering you, Streicher says it’s important to flag them sooner rather than later. 

Shepherd agrees. “When symptoms start or begin to interfere with daily activities, that is a good time to start seeing a doctor about it,” she says. 

As for what your healthcare provider can do? Malekzadeh says the way doctors approach both differs slightly.

“In perimenopause, care often focuses on stabilizing hormonal fluctuations and addressing irregular bleeding, mood variability, sleep disruption and early vasomotor symptoms,” she explains. “In menopause, when hormone levels are more consistently low, the focus shifts toward sustained symptom relief and long-term health considerations such as bone density, cardiovascular health and genitourinary symptoms.”

Whatever you do, Streicher says it’s important to talk to a healthcare professional about what’s going on.

“Don’t tough it out,” she says. “Perimenopause is the time to see someone and learn about your options.”