No bowel movement for over a month?

My partner has not had any bowel movement for over a month now and its starting to worry me more then it does her. She is about 10 stone max and for the past week she has really made a effort. She has stopped drinking coffee as well as eating alot of dried fruit, bran flakes, green tea & fiber supplements. She has tried laxatives before with no luck, does anyone have any advice on this?