What can cause irregular bleeding (4-9 weeks nonstop) while on bc, large blood clots, severe pelvic pain, & thin endometrium? ultrasound, laparoscopy, biopsy no results. been searching 2 years for an answer but no luck :(

A thin lining: is the result of the OCP, and is desired, to protect against excessive build up. However a very thin lining can also cause bleeding as you are seeing. SO discuss this with your doctor, sometimes taking a short break in the pill (use condoms), can allow the lining to thicken slightly controlling the bleeding. Then consideration of slightly different estrogen/progestin combo.