During pregnancy, heightened levels of estrogen and progesterone are responsible for many changes in the body. Women may experience both heightened sense of smell and taste. Heightened sense of taste during pregnancy is known as dysguesia. Dysguesia differs from the cravings or aversions that women may experience. This heightened sense of taste comes from changes in taste bud structure that causes women to experience tastes differently, making certain tastes, such as bitter flavors, much more acute.
Dysguesia may be due to the heightened sense of smell that women also experience during pregnancy. Higher levels of estrogen can make even the slightest smells seem overwhelming. Heightened sense of smell is experienced by all women during pregnancy, and can be a primary contributor to morning sickness. (See Reference 3)