What causes abnormal heavy bleeding for 20days so far after laparoscopic surgery for endometriosis and ovarian cysts and having prostap injection?

Bleeding. If you had surgery for endometriosis, that could cause your bleeding postoperatively. If you got any medications to reduce future endometriosis growth, this may cause continued bleeding as well. If you did get lupron, (leuprolide) the bleeding should diminish after 2-3 weeks and you may not have a period for 2 - 3 months. You should follow up with your doctor to discuss these symptoms.