The ovarian cycle may influence the exhaled volatile organic compound profile analyzed by an electronic nose

Introduction. We aimed to investigate whether the sex hormone profile during the ovarian cycle in healthy women could affect the volatile organic compound (VOC) profile analyzed by an electronic nose (e-nose). Methods. We enrolled 21 healthy, never-smoking, regularly menstruating women who were not taking any medications. A series of exhaled breath measurements were performed on all subjects at predefined intervals (days 1-6, 7-12, 13-19, 20-25 and 26-31; day 1 was the first day of menstruation) during their ovarian cycle and analyzed by an e-nose (Cyranose 320). Results. By principal component analysis, significant modifications of the exhaled VOC profile were observed over the cycle for principal component 1 (PC1; p = 0.001). In particular, the PC1 value was significantly higher during the premenstrual period and during menstruation compared with the first third of estrogen phase, mid-cycle and the first third of progestational phase (for all parameters p < 0.05 and p < 0.01, respectively). Subsequent linear discriminant analysis confirmed the above findings. Conclusions. The ovarian cycle may alter the exhaled VOC pattern and this should be taken into account during serial measurements of these markers in the female population.