What could be the reason for continuous heavy menustrual bleeding for 20 days? ttc, all tests(vag. scan, hsg ) are clear and everything is normal.

Hormones?: Extremes of weight (thin/heavy) can cause this, as can thyroid. You mentioned ultrasound and hsg are normal. Endometriosis and adenomyosis are also causes. If ttc, however, you can't really treat the bleeding b/c doing so would prevent possibility of pregnancy. If you've been ttc for awhile, consider seeing an infertility specialist to help you. Good luck!