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.
Sometimes, women in the early stages of pregnancy find that their sense of taste appears to have changed, possibly resulting in a bad taste in the mouth. Depending upon the cause of the sense of bad taste, there may be other associated symptoms, such as nausea or dry mouth. REFERENCE: