01

Why periods change in perimenopause

In your reproductive years, ovulation happens roughly once a month, and the hormonal cycle is predictable. In perimenopause, the ovaries become less consistent. Some months you ovulate, some months you don't. When ovulation doesn't happen, progesterone (the hormone that thins and sheds the uterine lining cleanly) doesn't get produced. Oestrogen keeps building the lining, and when it eventually sheds, it sheds more.²

The result, for most women, is some combination of:

• Heavier flow
• Longer periods
• Shorter cycles (closer together) early in perimenopause
• Longer gaps between periods as perimenopause progresses
• Spotting between periods
• Sudden floods with little warning

These patterns can shift month to month, which is part of what makes perimenopause confusing. Two months of nothing followed by a 10-day flood is not unusual.

02

What patterns are common

The most common perimenopausal bleeding patterns:

Heavier menstrual bleeding (menorrhagia)

Soaking through a pad or tampon every hour for several hours, passing clots larger than a 50-cent coin, or bleeding that lasts longer than 7 days. Heavy menstrual bleeding affects roughly 1 in 4 perimenopausal women³ and is a major cause of iron deficiency in this age group.

Shorter cycles

Periods arriving every 21–24 days instead of 28. Common in early perimenopause when follicles mature faster.

Skipped periods

Cycles of 40, 60, or 90 days are normal in late perimenopause. The official definition of menopause is 12 consecutive months without a period.

Spotting between periods

Light spotting in the middle of the cycle is usually hormonal, but persistent or post-sex spotting needs assessment.

"Flood and dry" patterns

Months of nothing followed by a heavy bleed. The lining has had time to build up, and when it sheds, it sheds heavily.

03

What's not normal

Some bleeding patterns are not just perimenopause and should be assessed promptly:

• Bleeding more than 12 months after your last period: any bleeding after this point is, by definition, postmenopausal bleeding and needs urgent investigation⁴
• Bleeding after sex (postcoital bleeding)
• Bleeding between periods that is persistent or heavy
• Periods so heavy they're causing iron deficiency, fatigue, or breathlessness
• Periods lasting longer than 7 days regularly
• Sudden onset of clots larger than a 50-cent coin
• Pelvic pain accompanying the bleeding that's new or worsening

The most important rule: any bleeding after 12 months without a period is never just menopause. Most causes are benign (polyps, atrophic vaginitis, hormone therapy effects), but it is also the most common warning sign of endometrial cancer, which is highly treatable when caught early.⁵

04

Causes worth knowing about

Heavy or irregular bleeding in perimenopause has several common causes beyond the hormonal swings of perimenopause itself.

Fibroids

Benign muscular growths in the uterus. Up to 70% of women have them by age 50,⁶ and they're a leading cause of heavy bleeding in perimenopause. Usually diagnosed on pelvic ultrasound.

Polyps

Soft growths in the uterine lining or cervix. Usually benign but can cause spotting, heavy bleeding, or bleeding between periods. Removed easily if symptomatic.

Adenomyosis

Endometrial tissue growing into the muscular wall of the uterus. Causes heavy, painful periods. More common in women in their forties.

Endometrial hyperplasia

Thickening of the uterine lining, often from unopposed oestrogen (oestrogen without progesterone). Can be benign or precancerous, which is why investigation matters.

Thyroid disorders

Hypothyroidism can cause heavy periods; hyperthyroidism can cause light or absent periods. A simple TSH blood test rules these in or out.

Bleeding disorders

Less common but worth considering, particularly if you've always had heavy periods or have a family history.

Endometrial or cervical cancer

The most important cause to rule out promptly, particularly with bleeding after menopause or persistent abnormal bleeding patterns.⁵

05

Treatments that work

Heavy or irregular perimenopausal bleeding is highly treatable. The right option depends on the cause, your other symptoms, and whether you still want to retain fertility.

Hormonal IUD (Mirena)

The single most effective treatment for heavy menstrual bleeding. Reduces bleeding by 80–95% within 3–6 months⁷ and is the first-line recommendation in Australian and international guidelines. Also provides contraception. Lasts 5–8 years. Side effects in early months (spotting, breast tenderness) usually settle.

Tranexamic acid

A non-hormonal medication taken during the heaviest days of your period. Reduces flow by 30–55%⁸ without affecting cycle length or fertility. Useful if you want to keep ovulating or can't have hormonal treatment.

Combined oral contraceptive pill

For women under 50 without cardiovascular risk factors, the combined pill regulates cycles, reduces flow, and provides contraception. Less commonly used in late perimenopause.

Menopausal hormone therapy (MHT)

For women with broader menopausal symptoms (hot flushes, sleep disruption, mood changes) alongside heavy bleeding, MHT can stabilise the hormonal swings. Often combined with a hormonal IUD for the progesterone component.

Endometrial ablation

A day-procedure that removes the lining of the uterus. Reduces bleeding significantly in 80–90% of women⁹ and is suitable when fibroids and polyps have been ruled out and fertility is no longer wanted.

Surgical options

• Hysteroscopic polypectomy or myomectomy for polyps and fibroids causing the bleeding
• Hysterectomy as a last resort when other treatments have failed or when there's a coexisting condition that justifies it

Iron replacement

Almost every woman with heavy perimenopausal bleeding has low iron stores, even if her haemoglobin is normal. Oral iron is first line; intravenous iron is faster and often better tolerated when bleeding is ongoing.

06

When to see your GP

Make the appointment this week if you have any of:

• Bleeding so heavy you're soaking pads hourly, passing large clots, or feeling lightheaded
• Bleeding that has lasted more than 7 days
• Bleeding between periods, after sex, or after 12 months without a period
• New pelvic pain alongside the bleeding
• Symptoms of iron deficiency: fatigue, breathlessness, dizziness, pale skin

What to ask for at the appointment

• A full blood count and ferritin: to assess iron stores, not just haemoglobin
• TSH: to rule out thyroid causes
• A pelvic ultrasound: to look at the uterine lining and check for fibroids, polyps, or adenomyosis
• An endometrial biopsy: if the ultrasound shows a thickened lining or if you've had postmenopausal bleeding
• A discussion of treatment options suited to your situation, not just "wait it out"

Own Your Menopause Appointment: 5 Tips from a GP walks through how to make the most of the visit and how to push back if the response is "it's just your age."

If you also have low energy or worsening fatigue alongside the heavy bleeding, read Perimenopause Fatigue for the iron-test specifics that matter.

07

What you can do

While treatment plans are being sorted out, a few things help day to day:

• Track every cycle. Date, duration, heaviness (light, moderate, heavy, flooding), any clots, any pain. Pattern recognition is what unlocks the diagnosis.
• Eat iron-rich foods. Red meat, chicken liver, lentils, leafy greens, fortified cereals. Pair plant sources with vitamin C to improve absorption.
• Limit alcohol and reduce caffeine during heavy weeks. Both can worsen bleeding and disrupt sleep.
• Avoid aspirin and high-dose ibuprofen during heavy periods unless prescribed. They can increase bleeding.
• Carry overnight supplies during the day when you're in a heavy phase. The unpredictability is the hardest part for most women, and being prepared takes the edge off it.

08

Why getting on top of this matters

Heavy perimenopausal bleeding is one of the most under-treated conditions in midlife women. Many women are told to "wait it out" until menopause finishes the job, but waiting can mean two to ten years of disrupted sleep, work absences, ruined clothes, and an iron deficiency that gradually erodes energy, mood, and cognition.

The treatments work. A Mirena, a course of tranexamic acid, or a hysteroscopic procedure can change daily life within weeks. The single most important thing is to get the bleeding investigated, get the cause identified, and get a treatment plan that suits you, rather than tolerating it as inevitable. Perimenopausal bleeding is treatable, and women who get the right intervention almost always wish they had pushed for it sooner.