Changes in gustatory sense during pregnancy.

Changes in gustatory sense were investigated in 97 pregnant women and in 30 healthy, non-pregnant women who served as controls. All 97 pregnant women completed a questionnaire regarding taste changes and 32 of them underwent serial tests of gustatory function, including electrogustometry and testing with filter paper disks placed over the areas of the chorda tympani nerve and glossopharyngeal nerve. All gustatory testing was performed by the same person. In addition, serum levels of trace elements were measured in 72 of the pregnant women. Of the 97 pregnant women, 90 (92.8%) reported in the questionnaire that they had experienced some type of change in taste during pregnancy, usually a change in sour taste (59 women; 65.6%). Pregnant women had higher gustatory thresholds than non-pregnant women, with an especially marked decrease in gustatory function being noticed in the first trimester. Although serum zinc levels decreased in pregnant women between the second and third trimesters, zinc levels were in the normal range in the early stage of pregnancy. Thus, it is difficult to explain dysgeusia in the early stage of pregnancy as being associated with a deficiency of zinc. The decrease in gustatory function during the first trimester is considered to be due to the notable changes in secretion of hormones that occur during this stage.