How your bowels work depends on many factors. This might include whether you have an infection or not as well as a range of other issues. Constipation is one of such bowel habits. If a patient has a tumor, it presses on the nerves responsible for quick movement of the bowel. The rectum is narrowed in case the mass presses on the intestines. All these make it difficult to defecate. If you have some kind of abdominal swelling and bloating and these two symptoms are accompanied by constipation, you should see the doctor to make sure that you are not suffering from ovarian cancer.