Hi, According to the description the possible causes are: - After completion of the periods depending on the influence of estrogen hormone, in the first half of the menstrual cycle, vaginal discharge can be seen. When this discharge mixed with the post menstrual remaining collected blood and shed endometrial tissue in the uterus that can appear as gray pieces. -Usually this type of discharge will subside soon and may not need any specific treatment. If the discharge persists, better to consult your gynecologist once, get to examined undergo an ultrasound. With this work up the possible cause of your problem can be identified and treatment can be taken accordingly. If there is any possibility of pregnancy better to go for a urine pregnancy test to rule out the possibility of incomplete abortion. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Sree Gouri S. R., OBGYN