My poop is black and smells like burning rubber/plastic, i am 28 weeks pregnant. should i be worried?

Black stools ?'s: At 28w pregnant, and taking pre-natal vitamins with iron, your stools may be dark and have a characteristic odor as described. If you are not anemic, it is usually not a cause for concern, but check with your OB physician for a test for occult blood in your stool, and another blood count to see if significant anemia is present.