Perimenopause, Part 2: The Bleeding Chaos — From Skipped Periods to the Flood
Perimenopause Series · Part 2 of 4
Last week we talked about the hormonal rollercoaster of perimenopause. This week we follow that chaos where it shows up most dramatically — your bleeding. If your periods have become wildly unpredictable, sometimes vanishing, sometimes flooding, there’s a clear reason why. And while much of it is normal for this phase, some of it needs attention.
In Part 1, I described the hormonal turbulence of perimenopause: progesterone falling first, estrogen swinging wildly, and ovulation becoming erratic. Nowhere does that chaos become more visible — or more disruptive — than in the menstrual cycle itself. Let me walk you through why.
Why the bleeding goes haywire: it all comes back to ovulation
Here’s the central concept, and once you understand it, the whole confusing picture snaps into focus: your bleeding pattern depends on whether or not you ovulate.
In a normal cycle, you ovulate, and that releases progesterone — the hormone that matures the uterine lining and, when it withdraws, triggers a clean, synchronized shed. That’s a regular period: organized, predictable, self-limited.
In perimenopause, many cycles are anovulatory — you don’t ovulate. And that changes everything in two very different directions:
Direction one: the skipped period
If you don’t ovulate and estrogen happens to be low that cycle, there may not be enough stimulation to build much lining — so the period simply doesn’t come. You skip it. This is one of the hallmarks of perimenopause, and by itself it’s usually nothing to worry about.
Direction two: the flood
Here’s the one that frightens women, and it’s worth understanding in full. When you don’t ovulate, you make no progesterone — but your estrogen (remember, it’s all over the place) keeps right on stimulating the uterine lining to grow. Estrogen builds; progesterone isn’t there to organize and stabilize it.
So the lining grows. And grows. With no progesterone to trigger a clean, synchronized shed, it just keeps thickening — unopposed. Eventually the lining becomes so thick it can no longer sustain itself, and it begins to break down in a disorganized way. The floodgates open. And because this bleeding isn’t driven by the normal hormonal choreography, it has no built-in signal to stop.
This is not a trivial amount of blood
I want to be clear about how serious this can get, because women are often told to just “wait it out.” I have seen patients drop their hemoglobin from a normal level of 13 to as low as 6 in a matter of weeks from this kind of unopposed, unrelenting bleeding. That is a profound, dangerous anemia. Heavy perimenopausal bleeding is a real medical issue — not something to endure in silence, and not something to be embarrassed about raising.
But hormones aren’t the only cause — why an evaluation matters
Although the anovulation story explains most perimenopausal bleeding, it’s a mistake to assume that’s always what’s going on. Several other causes can produce heavy or abnormal bleeding, and some can only be found by looking. This is why a proper evaluation — including a pelvic exam and usually a pelvic ultrasound — matters.
Structural causes in the uterus
Heavy bleeding can come from physical growths that may only be discovered on ultrasound performed to investigate the pattern:
- Fibroids — benign muscular growths in the uterine wall that can cause heavy, prolonged bleeding.
- Polyps — soft overgrowths of the lining that can bleed unpredictably.
The lining itself — and when to biopsy
If the ultrasound shows a thickened endometrial lining (greater than about 10 mm), an endometrial biopsy may be recommended to sample the tissue and rule out precancerous or cancerous changes. That said, this anovulatory thickening is extremely common in perimenopause, while endometrial cancer is not. So in many cases, a reasonable and effective approach is a few cycles of a progestin, which does the job the missing progesterone would have done — maturing and then shedding the lining in a single, controlled, synchronized bleed. Your physician will help decide which path fits your specific picture.
Don’t forget the cervix and other sources
Not all bleeding comes from the uterine lining, which is exactly why a physical exam is so important and shouldn’t be skipped in favor of ultrasound alone. Bleeding can arise from the cervix — for instance, from a cervical polyp, or, though far less common, a cervical cancer. These are things that must not be missed, and they’re found by looking. An exam is not an afterthought; it’s an essential part of a complete evaluation.
⚠ When bleeding needs prompt attention
Please don’t wait it out if you experience:
- Soaking through a pad or tampon every hour for several hours, or passing large clots
- Bleeding with dizziness, lightheadedness, a racing heart, or shortness of breath (signs of significant blood loss)
- Bleeding after intercourse or bleeding between cycles that’s new
- Any bleeding after you’ve fully gone through menopause (12 months with no period) — this always warrants evaluation
- Bleeding accompanied by severe pain or fever
What to check — the workup
When a woman comes in with heavy perimenopausal bleeding, the evaluation and the treatment discussion often happen at the same visit, because women need relief, not just answers. Alongside the exam and ultrasound, baseline labs almost always include:
- CBC (complete blood count) To measure how much blood has actually been lost — this is where I catch that dangerously low hemoglobin.
- Ferritin To assess iron stores, which are often depleted by heavy bleeding even before anemia shows up fully.
- TSH (thyroid) Because thyroid dysfunction is a common, easily-missed contributor to abnormal bleeding.
- Pregnancy test Yes, really. Pregnancy is still possible in perimenopause, and heavy bleeding can be a sign of miscarriage or other pregnancy-related issues. It must be ruled out.
How we treat it — you don’t have to just live with it
The good news: heavy perimenopausal bleeding is very treatable, and the conversation usually happens right alongside the evaluation. The main options, assuming no contraindications, include:
Effective treatment options:
- A progestin-releasing IUD (Mirena or Liletta): often the most effective option — it delivers progestin right to the uterine lining, dramatically reducing bleeding (many women stop bleeding almost entirely), and it lasts for years.
- Cyclic oral progestin: taking a progestin on a schedule to replace what the missing ovulation isn’t providing — restoring organized, controlled shedding.
- Combined oral contraceptive pills: for women without contraindications, these regulate the cycle, lighten bleeding, and provide contraception (still relevant in these years).
Which option is right depends on your health history, whether you need contraception, your other symptoms, and your preferences — a shared decision worth taking the time to get right.
The bottom line
- Bleeding chaos follows hormonal chaos — and it hinges on ovulation. No ovulation means no progesterone to organize the shed.
- That’s why you can skip periods (low estrogen, thin lining) or flood (estrogen builds the lining unopposed until it breaks down with no signal to stop).
- This bleeding can be dangerous — I’ve seen hemoglobin fall from 13 to 6 in weeks. Don’t wait it out.
- An exam and ultrasound matter — to catch structural causes (fibroids, polyps), a thickened lining that may need a biopsy, or a cervical source that must not be missed.
- Baseline labs: CBC, ferritin, TSH, and a pregnancy test (yes — pregnancy and miscarriage are still possible).
- It’s very treatable: a progestin IUD, cyclic oral progestin, or combined pills — usually discussed alongside the evaluation itself.
Heavy, unpredictable bleeding is one of the most disruptive parts of perimenopause — and one of the most fixable. You don’t have to endure it.
If your bleeding has become heavy, unpredictable, or frightening, please don’t tough it out — this is exactly the kind of thing worth being seen for, both to make sure nothing is being missed and to get you real relief.
Coming next in this series:
Part 3. All about why you develop a meno-belly and gain weight in midlife. It’s not just aesthetics; there can be some huge health ramifications. Stay tuned.
This article is for educational purposes and reflects general information about perimenopausal bleeding; it is not a substitute for individualized medical evaluation. Abnormal, heavy, or postmenopausal bleeding should always be assessed by your own clinician, as causes range from benign and hormonal to conditions that require prompt treatment. Any bleeding after menopause, bleeding with signs of significant blood loss (dizziness, rapid heart rate, shortness of breath), or bleeding during a known or possible pregnancy warrants urgent medical attention. Treatment decisions should be made together with your physician in the context of your personal health history.