Would diagnostic laparoscopy find ovarian cancer if there was any? i've had one, and ultrasounds and a colonoscopy but no cause for bloating found

Usually: Yes provided the ovaries were readily visible and you had a thorough laparoscopy.. Bloating is often caused by excessive fiber along with inadequate fluids and all of the exams you had would all be negative. Try modifying your diet, cut out caffeine and drink 80-100 oz of fluids per day for 10-15 days. Simethicone and charcoal tablets may also help as will probiotics.

Ovarian cancer: Yes, a diagnostic laparoscopy should have found an ovarian/peritoneal/fallopian tube cancer. There are many other more common causes of bloating to think about: gall bladder disease, ulcer disease, lactose intolerance, sprue, diet issues ...