Periods coming more often and heavier in perimenopause: why, and what to do

The short version

• Shorter cycles come first, skipped cycles come later. Rising FSH speeds up follicle recruitment, the follicular phase shortens, and cycles can drop to 21 to 24 days before they ever start getting longer.
• A cycle-length swing of seven days or more is the marker. STRAW+10 staging defines the early menopausal transition by persistent variability of at least seven days between consecutive cycles, which is why tracking length beats tracking symptoms alone.
• Anovulatory cycles make bleeds heavier. No ovulation means no progesterone, so estrogen builds an unstable lining that sheds heavily and unpredictably.
• Heavy is defined by impact, not by comparison. Soaking through hourly, clots over an inch, bleeding beyond seven days, or a period that dictates your calendar all qualify for treatment.
• Structural causes hide behind hormones. Fibroids, polyps, adenomyosis, thyroid disease, bleeding disorders, and endometrial hyperplasia all present as heavy perimenopausal bleeding and all need excluding.
• Iron is the missed diagnosis. Ask for ferritin, not just hemoglobin. Fatigue and hair shedding blamed on hormones are frequently iron.
• Effective treatment exists and it is not just "wait it out." Hormonal coil, tranexamic acid, NSAIDs, combined contraception, cyclical progestogens, ablation, and hysterectomy, in roughly that order of escalation.

Why cycles get closer together before they get further apart

The ovary does not shut down smoothly. As the pool of remaining follicles shrinks, the brain compensates by raising follicle-stimulating hormone. Higher FSH early in the cycle recruits a follicle faster than it used to, so the follicular phase, the first half of the cycle, contracts. The luteal phase after ovulation stays fairly fixed at roughly 12 to 14 days, so when the first half shortens, the whole cycle shortens with it. That is why a woman who ran like clockwork on 28 days at 38 can be bleeding every 23 days at 43.

Those short cycles are frequently paired with a high-estrogen surge. Perimenopause is not a smooth estrogen decline: estradiol can spike well above premenopausal levels during this phase, which is why breast tenderness, migraines, mood volatility, and heavier bleeding often intensify at exactly the point when everyone is telling you your hormones are "running out."

Later in the transition the pattern reverses. Ovulation becomes intermittent, cycles stretch, and you start skipping months. Under STRAW+10, an interval of 60 days or more without bleeding marks the late menopausal transition. Many women move through both phases and remember only the second one, which is part of why the crowded-period phase gets so little airtime.

Why the bleeding gets heavier

Two mechanisms stack. First, anovulation. In a cycle where no egg is released, the corpus luteum never forms, so progesterone is never produced. Progesterone is what converts a proliferating lining into a stable, organized one that sheds cleanly. Without it, estrogen keeps building the endometrium until it outgrows its blood supply and breaks down unevenly. The result is a bleed that is heavier, longer, cloudier with clots, and impossible to predict.

Second, the years-long estrogen exposure of your 40s is fertile ground for structural change. Fibroids commonly grow and become symptomatic in this decade, adenomyosis (endometrial tissue growing into the uterine muscle) produces heavy bleeding with deep cramping and a bulky uterus, and endometrial polyps cause both heavy periods and bleeding between them. None of these are diagnosed by how you feel, which is the whole argument for an ultrasound rather than another year of guessing.

What counts as heavy: the working definitions

The formal research definition of heavy menstrual bleeding is more than 80 mL of blood loss per cycle, which is useless at the kitchen table. What clinicians and guidelines actually use are functional markers. Treat any of these as reason to ask for help:

• Soaking a regular pad or tampon every one to two hours for several hours in a row.
• Needing a pad and a tampon, or a period cup and backup, together.
• Passing clots bigger than roughly the size of a quarter.
• Bleeding for more than seven days, or a cycle shorter than 21 days that persists.
• Getting up overnight to change protection.
• Planning clothing, travel, exercise, meetings, or sex around your bleeding.
• Any bleeding that leaves you dizzy, breathless on stairs, or wiped out for days afterward.

Note the last two. Guidelines are explicit that heavy menstrual bleeding is defined by its effect on quality of life, not by a volume you are expected to measure or by whether your sister's period is worse.

Red flags: bleeding that needs looking at, not tolerating

Perimenopause explains a great deal of bleeding change. It must not be allowed to explain all of it. Book an appointment for:

• Bleeding or spotting between periods.
• Bleeding after sex.
• Any bleeding at all after 12 consecutive months without a period. This is postmenopausal bleeding and always needs assessment.
• Periods consistently longer than seven days.
• Cycles consistently shorter than 21 days, or a sudden dramatic change from your own normal.
• Heavy bleeding alongside pelvic pain, pressure, a bloated lower abdomen, or urinary frequency.
• Heavy bleeding while on tamoxifen, on unopposed estrogen, or with risk factors for endometrial cancer such as obesity, PCOS, diabetes, or a family history of Lynch syndrome.

Seek same-day or emergency care for soaking through more than two pads an hour for two consecutive hours, bleeding with fainting, chest pain, breathlessness, or a heart rate that will not settle. That is acute blood loss and it is treatable quickly.

The workup to expect

1. Bloods. Full blood count plus ferritin. Thyroid function, since both under- and overactive thyroid alter bleeding. Clotting studies or von Willebrand testing if you have bled heavily since your very first period, or bruise and bleed easily elsewhere.
2. Pregnancy test where relevant, because erratic short cycles still ovulate.
3. Pelvic ultrasound. Transvaginal is the standard approach, looking for fibroids, polyps, adenomyosis, and endometrial thickness.
4. Endometrial biopsy if the lining is thickened, if bleeding is between periods, if you have risk factors, or if treatment is not working. It is a quick office procedure and it is how hyperplasia gets caught early, while it is still fully treatable.
5. Not FSH. Over 45, guidelines advise diagnosing perimenopause on symptoms and cycle pattern rather than hormone levels, because a single FSH reading in a phase defined by hormonal volatility tells you very little.

The treatment ladder that reduces blood loss

• Levonorgestrel intrauterine system (hormonal coil). First-line in guidelines for heavy menstrual bleeding. Typically reduces blood loss by 70 to 95 percent within three to six months, is also contraception, and covers the progestogen requirement if you add estrogen later. Expect irregular spotting for the first three to six months before it settles.
• Tranexamic acid. Non-hormonal, taken only on heavy days, reduces blood loss by roughly a third. A good option if you do not want hormones or need something to use immediately while waiting on imaging.
• NSAIDs (naproxen, mefenamic acid, ibuprofen). Modest reduction in blood loss with a real reduction in cramping. Started at the first sign of bleeding and taken through the heavy days, they work better than reaching for them on day three.
• Combined hormonal contraception. Regulates cycle timing, lightens bleeding, and can be run continuously to skip periods altogether. Suitable for many healthy non-smokers under 50, with migraine-with-aura, hypertension, and clot history being the usual contraindications to discuss.
• Cyclical or continuous progestogens. Useful when the problem is clearly anovulatory bleeding, providing the progesterone signal your cycle is no longer producing.
• Targeted treatment for structural causes. Polyps can be removed hysteroscopically, fibroids treated with medication, embolization, or myomectomy depending on size and location.
• Endometrial ablation. A day procedure that destroys the uterine lining, highly effective for bleeding when childbearing is complete. It is not contraception and it is not recommended if future pregnancy is wanted.
• Hysterectomy. Definitive, and reserved for when other options fail, are declined, or when structural disease warrants it.

Worth stating plainly: standard menopausal hormone therapy doses are for symptoms like hot flashes and broken sleep. HRT is not a heavy-bleeding treatment on its own, and adding estrogen without adequate progestogen cover can make bleeding worse. Bleeding gets its own plan, ideally in the same conversation.

The iron conversation nobody starts

Heavy menstrual bleeding is the leading cause of iron-deficiency anemia in women before menopause, and iron stores can be depleted long before hemoglobin drops, which means a "normal" blood count can still sit on top of significant deficiency. The symptoms overlap so completely with perimenopause, fatigue, brain fog, breathlessness, hair shedding, cold intolerance, restless legs, that they are routinely attributed to hormones and left untreated for years.

Ask for ferritin by name. If it is low, treatment is oral iron (often better absorbed on alternate days than daily, taken with vitamin C and away from tea, coffee, and calcium) or intravenous iron when oral iron is not tolerated or not working. Then re-test. Fixing iron does not fix perimenopause, but it very often returns a chunk of your energy that you had written off permanently.

What to do this month, practically

1. Log the numbers, not the vibes. Cycle start dates, days of bleeding, products used per day, clot size, flooding incidents, pain score, and energy the day after. Three cycles of this is more persuasive than any description.
2. Calculate your variability. Compare the length of your last several cycles. A persistent swing of seven days or more is the documented marker of the early transition, and it is a concrete number to hand a clinician.
3. Start what is safe to start. An NSAID from the first sign of bleeding, and ask about tranexamic acid for the heavy days while investigations are pending.
4. Ask for ferritin with your blood count. Bring the fatigue symptoms up in the same appointment so they get connected rather than filed separately.
5. Protect the ordinary things. Period underwear and cups for high-capacity days, a spare kit in your bag and car, and a dark towel by the bed. Not a solution, but it lowers the daily cost while the plan is being sorted.

What to say at the appointment

"I'm [age]. Over the last [X] months my cycles have shortened from [28] days to [22] days, and my bleeding has become much heavier: I'm soaking a pad every [hour or two] on the worst days, passing clots, and bleeding for [8] days. It's affecting [work, exercise, sleep]. I'd like a full blood count and ferritin, thyroid function, and a pelvic ultrasound to check for fibroids, polyps, and adenomyosis. I'd also like to discuss tranexamic acid for the heavy days and whether the hormonal coil is appropriate for me."

If the response is that this is just perimenopause and you should wait it out, it is fair to ask directly: what would we do differently if this bleeding were caused by a polyp or hyperplasia, and how are we ruling those out? Heavy bleeding at this age is common enough to be expected and specific enough to be worth investigating. Both things are true.

How PeriSlayer connects this to the wider pattern

Bleeding pattern is the single most diagnostically useful thing you can track in perimenopause, and it is the hardest to reconstruct from memory once cycles stop being predictable. PeriSlayer logs cycle length, flow volume, clots, and pain alongside sleep, mood, migraines, energy, and hot flashes, then surfaces the variability and the correlations, so you can see the seven-day swing appear, watch the fatigue track the heavy months, and walk into an appointment with a chart instead of an apology.