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.
Things that are known to cause a metal-like taste, and may create a metallic smell bad breath, include stomach problems such as heartburn, jaundice, metal poisoning, other types of poisoning, dental problems, many drugs, and pregnancy.