Hi, Thanks for posting in HCM. I understand your concern. The following are the common causes for passage of blood clots during or soon after the periods: Iron deficiency anaemia, Deficiency of biologically active substances and minerals (vitamins C and K), Intrauterine manipulations such as miscarriages or abortions, Endometriosis (adenomyosis), Myoma, Endometrial hyperplasia or polyposis and Abnormalities in the uterine development. If your periods are regular, moderately painful and occasionally you have clots in your menstrual discharge, then there is no reason to panic. However, in order to make sure there are no hidden inflammatory processes in your reproductive tract, such as endometriosis or uterine fibroids, get your blood tested for coagulation profile as well as get an ultrasound scan done. Kindly consult Gynaecologist with the reports for evaluation and appropriate management. Hope the information provided would be helpful. All the best.