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.
A metallic taste in your mouth is a type of taste disorder known medically as parageusia. This unpleasant taste can develop suddenly or over longer periods of time. To understand what causes a metallic taste you must first understand how taste works. Your sense of taste is controlled by your taste buds and your olfactory sensory neurons.