Hi,
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Heavy periods or change in menstrual bleeding pattern could be indicative of hormonal issues, internal hurt and clot, or other problems like ovarian or uterine issues (ovarian cysts, uterine fibroids, polyps etc). You will need to visit a gynecologist for a thorough examination and ultrasound scan, hormonal work-up, blood work-up to look for the exact cause for your changed bleeding pattern. The investigation results will also help to find if these are due to perimenopausal changes.
Take care.