What causes the mouth to taste like metal?

Dysgeusia: is a change in your sense of taste due to a variety of causes; from medication you may be taking to dental problems. In your case pregnancy-related (estrogen) changes in your sense of smell may also lead to dysgeusia. It is very common condition in pregnancy and will be solved soon. With Geographic tongue people may notice they have a“bitter” or “metallic” taste in their mouths. Good luck.