A brief sudden change in a normally constant quantity: a pulse of current; a pulse of radiation. b. Any of a series of intermittent occurrences characterized by a brief sudden change in a quantity.
Some pregnant women experience a metallic taste in their mouth during the early stages of pregnancy, because of the hormone changes. It's also fairly common to crave certain foods, or go off certain foods, and have a heightened sense of smell. Learn more about the signs and symptoms of pregnancy.
Having such a taste in your mouth can also be caused by medication or by a physical condition which triggers an upset in your body chemistry. Bleeding gums is the most common cause of a metal taste. common cause is from bleeding, because the pigment in red blood cells contains iron. If you bite your tongue by accident, suffer trauma to the mouth, or have gum disease which can cause spontaneous bleeding from inflamed gums, then you will likely have a metal taste for a while, or notice it now and again.