Perimenopause

What perimenopause is

From your late 30s, the number of eggs left in the ovaries falls faster. Ovulation becomes less regular, and hormone levels swing widely. Estrogen can be higher than normal in some cycles and very low in others, while progesterone falls because you ovulate less often. These swings, rather than a steady decline, cause most perimenopause symptoms.

Perimenopause vs menopause

For what happens after periods stop, see menopause.

Stages of perimenopause

• Early perimenopause: cycle length changes by 7 days or more from your usual, for example a 28-day cycle becoming 21 or 35 days.
• Late perimenopause: gaps of 60 days or more between periods. Hot flashes are most common in this phase. Menopause usually follows within 1 to 3 years.

Perimenopause symptoms

Period changes

• Cycles that are shorter, longer, or unpredictable.
• Heavier periods, sometimes with flooding and clots, especially early on when estrogen can be high.
• Lighter periods or skipped months later on.
• Spotting between periods.

Other common symptoms

• Hot flashes and night sweats: sudden waves of heat and flushing lasting 1 to 5 minutes.
• Sleep problems: waking at night, often with sweats, and difficulty getting back to sleep.
• Mood changes: irritability, anxiety, low mood, and worsening of premenstrual symptoms. The risk of depression rises during the transition.
• Brain fog: forgetfulness and trouble concentrating, usually temporary.
• Vaginal dryness and pain during sex.
• Lower sex drive.
• Breast tenderness.
• Headaches, including worse menstrual migraine.
• Joint and muscle aches.
• Bladder changes: urgency and more urinary infections.
• Weight gain around the middle, and changes in skin and hair.
• Palpitations.

About 3 in 4 women have hot flashes at some point in the transition. Symptoms vary greatly: some people notice little, while others are significantly affected.

When perimenopause starts and how long it lasts

Most women notice changes between 40 and 50. Average onset is in the mid-40s. It tends to start earlier in smokers and in women whose mothers had an early menopause. Perimenopause lasts about 4 years on average, though hot flashes can continue for 7 years or more in total, spanning into the years after menopause.

Symptoms before 40 are not typical perimenopause and should be checked for early menopause or other causes.

Diagnosis

Perimenopause is usually diagnosed from your age, symptoms and period pattern. For women over 45 with typical symptoms, guidelines advise against routine hormone blood tests, because FSH and estrogen levels fluctuate so much that a single result is unreliable.

Your doctor may check:

• A pregnancy test if a period is late.
• Thyroid function, since an overactive or underactive thyroid can mimic perimenopause.
• A blood count if periods are heavy, to look for iron deficiency anemia.
• FSH, if you are under 45 or the picture is unclear.
• Pelvic ultrasound or a biopsy of the womb lining for very heavy, prolonged or irregular bleeding, to rule out fibroids, polyps or endometrial thickening.

Perimenopause treatment

Lifestyle measures

• Layer clothing, keep the bedroom cool and use a fan.
• Identify triggers: hot drinks, alcohol, spicy food and stress.
• Regular exercise improves sleep, mood and bone health.
• Strength training helps maintain muscle and bone.
• Stop smoking and keep a healthy weight; both reduce hot flashes.
• Cognitive behavioral therapy (CBT) reduces the impact of hot flashes and improves sleep.

Hormonal options

• Low-dose combined birth control pill, patch or ring: controls irregular periods, eases hot flashes and provides contraception, if you have no reasons to avoid estrogen such as migraine with aura, smoking over 35 or a clot history.
• Hormone therapy (HT or HRT): estrogen with a progestogen (if you have a uterus) is the most effective treatment for hot flashes and night sweats. For most healthy women under 60 or within 10 years of menopause, benefits outweigh risks.
• Hormonal IUD: controls heavy bleeding and protects the womb lining when combined with estrogen.
• Vaginal estrogen: low-dose creams, tablets or rings treat dryness and bladder symptoms with minimal absorption.

Non-hormonal options

• Fezolinetant: a non-hormonal tablet that blocks a brain signal driving hot flashes.
• Certain antidepressants (SSRIs or SNRIs), gabapentin or oxybutynin for hot flashes.
• Vaginal moisturizers and lubricants.
• Treatment for heavy bleeding: tranexamic acid, NSAIDs or the hormonal IUD.

Herbal products such as black cohosh have inconsistent evidence, and supplements are not regulated like medicines. Tell your doctor if you take them.

Contraception during perimenopause

You can still become pregnant until menopause. Use contraception until you have had no periods for 12 months if you are over 50, or for 2 years if you are under 50. Most women can stop all contraception by 55.

Long-term health

Falling estrogen speeds bone loss and changes cholesterol levels. This is a good time to review blood pressure, cholesterol, blood sugar and bone health, and to keep up exercise, calcium and vitamin D intake.

Frequently asked questions

What are the first signs of perimenopause?

The first sign is usually a change in your periods: cycles becoming shorter, longer or less predictable, or heavier or lighter bleeding. Other early signs include worse premenstrual symptoms, sleep problems, night sweats, hot flashes, mood swings and breast tenderness.

At what age does perimenopause start?

Most women start perimenopause in their 40s, on average around 45 to 47. Some notice changes in their late 30s. It tends to start earlier if you smoke or if your mother had an early menopause. Symptoms before 40 should be checked by a doctor.

How long does perimenopause last?

On average about 4 years, but it varies from a few months to around 10 years. It ends at menopause, defined as 12 months without a period. Hot flashes may continue for several years after periods stop.

Can you get pregnant during perimenopause?

Yes. Ovulation becomes irregular but still happens, so pregnancy is possible. Use contraception until you have had no periods for 12 months if you are over 50, or 2 years if you are under 50. A low-dose combined pill or hormonal IUD can also ease symptoms.

What is the difference between perimenopause and menopause?

Perimenopause is the transition years when hormones fluctuate and periods become irregular, but still occur. Menopause is the point when you have had no periods for 12 consecutive months. After that, you are postmenopausal.

Is there a test for perimenopause?

There is no single reliable test. After 45, doctors diagnose perimenopause from symptoms and period changes. Hormone levels such as FSH vary from day to day, so a normal result does not rule it out. Tests are more useful under 45, or to check the thyroid.