What would cause consistent, triangular bowel movements? Every time I try to have a bm, I push harder than I did birthing my child. I had a 6 cm mass removed, via a robotic assisted, low, anterior resection for colon cancer, 5 months ago. I am a 41 year old female, with no history of cancer on the maternal-paternal sides of my family. I also have IBS-C. My Gastro suspects a possible narrowing and has scheduled a flex-sig.