Constipation question...

Has anyone taken prenatals that make you constipated? I know this may be tmi but I swear when I have a bowel movement, I can tell it's harder now and I swear I feel it rip my anus! It bleeds just a little but it worries me! I've been taking lots of fiber and I can tell that its getting better and healing but I'm laying off vitamins until I'm back to normal!