I am pregnant and my stool is very dark. Is that normal?

It can be. Often, pregnant women may be prescribed medication, such as iron supplements which may change the appearance of the stool. Also reassess your dietary habits. Dark foods can cause this, too. "dark, tarry" stools can be an idicator of blood in the stool. See your md if this is a persistent problem & you can't identify any obvious cause. A simple test can be performed in the office or at home.