Changes in Concentration of Volatile Sulphur Compounds of Mouth Air during the Menstrual Cycle

Five female subjects were studied to determine the applicability of volatile sulphur analysis of mouth air to monitor chemical, cytological and physiological changes observed during the menstrual cycle. Volatile sulphur results were compiled over twelve ovulatory cycles derived from two or three consecutive cycles from each subject. The results of mouth air evaluations were compared with concurrently determined levels of hormones in blood serum and organic metabolites in vaginal secretions. Distinct cyclic variations were observed in concentrations of all three volatile sulphur components (hydrogen sulphide, methyl mercaptan and dimethyl sulphide) of mouth air. There was a definite overall trend for the compounds to increase two- to four-fold immediately around mid-cycle and menstruation as well as during mid-proliferative and mid-luteal phases of each menstrual cycle. In those cycles in which hormonal profiles were obtained, the increase in volatile sulphur content closely coincided with the mid-cycle surge in luteinizing hormone, while the peak during the mid-luteal phase corresponded to a period of maximum level of progesterone and elevated oestrogens. The concentrations of lactic acid and urea in vaginal secretions also underwent cyclic changes analogous to those described for volatile sulphur components of mouth air. The occurrence of malodourous concentrations of hydrogen sulphide and methyl mercaptan immediately around menses in most of the cycles studied satisfactorily accounts for the reported incidence of breath malodour observed during this time.