Medically reviewed on February 17, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
People with ovaries are born with a limited number of eggs. There are about one million eggs at birth, and that number decreases with age. By the time of the first menstrual cycle, there are about 300,000 to 400,000 eggs remaining .
For healthy people in their 20s or early 30s, the chances of conceiving each month are 25%-30%. But by the time a person is 40 years old, the chances are about 10% (or less) each month .
Perimenopause and menopause overlap and are easy to mistake for each other, but it’s worth understanding the differences between the two. Learn more about perimenopause and menopause below (and consider checking in on perimenopause-related hormones with the at-home Perimenopause Test).
While the start of menopause is more concrete, perimenopause is a transitional state (peri is derived from the Greek word for “near” or “around”). Perimenopause is the body’s gradual transition into menopause. Perimenopause typically starts in the 40s , though this transition period can vary from person to person.
Perimenopause contributes to various physical changes, which are primarily brought on by fluctuating estrogen levels. Estrogen levels go up and down during a normal menstrual cycle fairly predictably. These levels are controlled mainly by luteinizing hormone (LH) and follicle-stimulating hormone (FSH). FSH stimulates follicles to produce estrogen. Once the estrogen hits a certain level, the brain tells the pituitary gland to switch off the FSH production and switch on the LH production. Luteinizing hormone then tells the ovaries to release an egg, the process known as ovulation .
By your late 30s, the body doesn’t produce as much progesterone or estrogen, leading to fewer ovulations. Sudden spikes or extreme drops in estrogen may occur. FSH and LH hormones may also fluctuate, sometimes spiking as an attempt to increase estrogen production . High FSH levels may suggest that perimenopause has begun .
Many people have questions about perimenopause. Here are some of the most common queries:
Yes, but by the time a woman is 40 years old, the chances are about 10% (or less) each month . As you still have a period, you can get pregnant. This means pregnancy is possible during perimenopause, but the chances of conception are slimmer. Fortunately, there are fertility treatments you can explore. Another method is to take progesterone. Progesterone is the hormone that prepares the body for pregnancy.
Perimenopausal women can experience quick and drastic shifts in moods. Medical practitioners suspect that women with strong premenstrual symptoms are more likely to exhibit perimenopause mood changes , but further research is needed to draw more explicit conclusions. Other symptoms of perimenopause mood swings can include irregular periods, insomnia, vaginal dryness, and loss of libido.
Identifying the exact symptoms of perimenopause can be difficult. Some symptoms may overlap with the general effects of getting older, and, with menopause, not everyone experiences the same symptoms with the same levels of significance. The most common symptoms may include:
While most people associate hot flashes and night sweats with menopause, they can also occur during perimenopause. About 35 to 50 percent of women in perimenopause experience hot flashes in some form. They can vary from slight warmth to extreme feelings of heat that cause you to sweat through clothes. The sudden waves of heat can last up to 10 minutes at a time .
Periods still occur during perimenopause, but they may come irregularly. This can be hard to determine if your cycles were never regular, but in perimenopause, a period may come at least a week later than usual. In late-stage perimenopause, you may experience a 60-day gap between cycles .
About 10 to 20 percent of women will experience mood symptoms during perimenopause, though it can be difficult to pinpoint the exact cause of these changes. It’s generally a myth that perimenopause and menopause cause irritability on their own, but the effects of perimenopause may bring extra stress that can contribute to irritability and anxiety, while hormone fluctuations may make someone more vulnerable to symptoms of depression .
As hormones continue to fluctuate, perimenopause eventually leads to menopause. Menopause marks the end of the ability to get pregnant naturally. You're considered to have officially entered menopause after 12 consecutive months have passed since your last period. Menopause can happen in your 40s or 50s, but the average age is 51 in the United States .
Much like during perimenopause, each person will experience different menopause symptoms. Most of the symptoms of menopause are carryovers from your perimenopause symptoms. For example, hot flashes and night sweats may become more frequent in the later stages of perimenopause and extend into menopause. Many women continue to experience hot flashes nearly ten years after entering menopause, but the severity of the hot flashes declines after about two years .
The main difference between perimenopause and menopause is the lack of a period. Where perimenopause may be noted by irregular periods, menopause marks the complete end of a menstrual cycle. This also means that, while you can’t get pregnant in menopause, there’s still a chance you can get pregnant during perimenopause.
One commonly prescribed treatment to combat menopause symptoms is hormone therapy. Menopausal hormone therapy comes in two forms: systemic hormone therapy and low-dose vaginal products. However, there may be risks to some of these treatments, including breast cancer, blood clots, and/or heart disease.
Menopause may also increase the risk of coronary artery disease, characterized by narrowing arteries around the heart muscle. This is partly because estrogen contributes to healthy arteries, but the risk of coronary artery disease is largely caused by other problems, like reduced physical activity or unhealthy lifestyle factors (like smoking and excessive drinking).
Many think that weight gain is also associated with menopause. Menopause might contribute to weight gain, but it isn't the only reason. Other contributing factors include age, lifestyle, and genetic factors. Gaining weight during menopause has other risks, such as an increased chance of developing heart disease or type 2 diabetes. To avoid these risks, incorporate lifestyle changes, such as exercise, a healthy diet, and stress-reducing exercises.
It’s important to understand that menopause is not a disease or a disorder. It’s a normal part of life and aging. This doesn’t mean it’s without its complications, but with some planning and some help from healthcare professionals, you can still maintain a normal life. If you think you may be entering perimenopause, consider using an at-home Perimenopause Test with Everlywell.
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4. Perimenopause and Menopause: What’s the Difference? Everyday Health. URL. Accessed February 17, 2022.
5. Menopause - symptoms and causes. Mayo Clinic. URL. Accessed February 17, 2022.