Perimenopause · Menstrual health
Heavy periods with clots in perimenopause: what's normal and what's not
Heavy bleeding and quarter-size clots become common in the 40s. Most is driven by falling progesterone and unopposed estrogen. Some is not. Knowing the difference is critical.
Why perimenopause causes clots
As ovulation becomes irregular, cycles run with high estrogen and low progesterone. The endometrium overgrows, then sheds all at once. Fast heavy bleeding outpaces the plasmin system that keeps menstrual blood liquid — you see clots.
Red flags (see a clinician now)
- Soaking a pad or tampon every hour for 2+ hours
- Clots larger than a US quarter
- Periods lasting more than 7 days consistently
- Bleeding between periods
- Any bleeding after 12 months of no period (postmenopausal bleeding)
- Dizziness, shortness of breath, or fatigue (possible iron deficiency anemia)
Common causes beyond hormones
- Uterine fibroids
- Endometrial polyps
- Adenomyosis
- Endometrial hyperplasia
- Rarely, endometrial cancer (especially over 45)
Treatment options
- Cyclic micronized progesterone — 100-200 mg, days 14-28
- Levonorgestrel IUD (Mirena) — reduces flow 80-90%
- Tranexamic acid — during period days, reduces flow ~50%
- Endometrial ablation — for women done with childbearing
- Iron replacement — often needed alongside
Frequently asked questions
Are large blood clots during your period normal in perimenopause?
Small clots (dime-size) are usually normal. Clots larger than a quarter, or soaking a pad/tampon every hour for 2+ hours, meet criteria for heavy menstrual bleeding (menorrhagia) and warrant evaluation.
What causes clots during period?
Fast bleeding overwhelms the anticoagulant proteins in menstrual fluid, so blood clots inside the uterus. Perimenopausal anovulation raises estrogen relative to progesterone, thickening the endometrium and increasing flow.
When should I worry about heavy periods after 40?
Bleeding through pads hourly, clots larger than a quarter, periods lasting >7 days, bleeding between periods, or any postmenopausal bleeding — all require evaluation to rule out fibroids, polyps, or endometrial pathology.
What is a "blood clot in uterus"?
Menstrual clots form when heavy bleeding overwhelms natural anticoagulants. True uterine blood clots outside menstruation are rare and usually related to retained tissue or coagulation disorders — see a clinician.
What treatments work for heavy perimenopausal bleeding?
Options include cyclic progesterone, hormonal IUD (Mirena), tranexamic acid during periods, low-dose combined pill if appropriate, and endometrial ablation. Iron replacement is often needed alongside.
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Medically reviewed by Kindr Health Clinical Team · Last reviewed 2026-06-19. Compounded medications are prepared by FDA-registered 503A pharmacies and are not FDA-approved drug products.