Perimenopause is the time leading up to the end of your periods. During this transition, your body may change in ways you don’t expect, even if you’ve watched loved ones go through it. Perimenopause mainly causes symptoms linked to the shifts in reproductive hormones like estrogen. Your ovaries gradually produce less of these hormones, and your menstrual cycle becomes irregular before eventually stopping for good. When you’ve had 12 months without a period, you’ve officially entered menopause.

Reproductive hormones affect more of your body than you might think. That’s why perimenopause symptoms can vary so much. Let’s take a closer look at how perimenopause can affect 12 different parts of your body.

Brain

The hormone changes in perimenopause and menopause can shift how you think and feel. Hormonal changes can increase feelings of anxiety, irritability, depression, and unpredictable mood swings. You might also have trouble sleeping at night and notice brain fog or forgetfulness during the day. Headaches are also common during this time.

Heart

Estrogen supports your cardiovascular health. In the menopausal transition, it’s common to experience higher blood pressure or cholesterol levels, or a racing or pounding heartbeat. You may have as many as 16 extra beats per minute due to perimenopause-related hormone fluctuations. This decline in estrogen can increase the risk of developing heart disease.

Joints

Hormones also affect how your body moves and feels. Have you noticed painful, stiff, or swollen joints that don’t usually feel that way? You’re not imagining these symptoms. Up to 50 percent of perimenopausal women report joint pain and stiffness. You’ll usually feel it most in the morning.

Skin

Hormone changes can cause thinner, drier, itchier skin. You might also notice you’re sweating more or feeling hotter. Hot flashes and night sweats together are called vasomotor symptoms, which are common in perimenopause and menopause.

Genitals

Up to 84 percent of postmenopausal women have symptoms affecting their genitals and urinary system. These can show up differently for everyone, and they often get worse with time if left untreated. Some symptoms are most noticeable during sex, like vaginal dryness and pain. Others, like frequent urinary tract infections and urinary incontinence, may affect your daily comfort or bathroom habits.

Uterus

During perimenopause, you’ll notice changes in your menstrual period. Periods become less predictable and may be lighter or heavier than you’re used to. You may also spot between periods or notice your cycle coming closer together or farther apart.

Bones

Estrogen helps keep your bones strong. When you lose estrogen in menopause, your risk for bone conditions like osteoporosis increases, especially during the first three to five years after your last period. After menopause, bones can become weaker and more likely to break.

Belly

Menopause-related hormone changes, combined with lifestyle changes in midlife, can alter your body’s weight distribution. Weight gain around the abdomen is especially common in menopause, even if your diet and exercise habits haven’t changed much.

Eyes

More than half of women in perimenopause or menopause report having dry eyes. Hormone changes in menopause affect the chemical makeup of your tears, causing them to evaporate quickly and leave your eyes dry. Your eyes may also feel gritty, watery, or sensitive to light.

Mouth

Menopause doesn’t only dry out your eyes and skin. Dry mouth and a burning sensation in the mouth are also common. Research suggests that postmenopausal women may have a slightly increased risk of oral cancer, and hormone changes after menopause may play a role. It’s a good idea to keep up with regular dental checkups and mention any soreness or changes in your mouth.

Hair

Changes in your hormones during and before menopause can cause your hair to get thinner or fall out. Your hair can also change texture, becoming coarse, wiry, or curly. These changes happen because estrogen helps your hair grow and stay dense.

Breasts

Your breasts may feel tender during perimenopause, much like they commonly do at certain points in your menstrual cycle. Your breasts may also lose density. It’s important to get regular breast cancer screenings, as around 80 percent of breast cancer diagnoses affect women over 50.