Natural menstrual rhythm and oral contraception diversely affect exhaled breath compositions

Abstract

Natural menstrual cycle and/or oral contraception diversely affect women metabolites. Longitudinal metabolic profiling under constant experimental conditions is thereby realistic to understand such effects. Thus, we investigated volatile organic compounds (VOCs) exhalation throughout menstrual cycles in 24 young and healthy women with- and without oral contraception. Exhaled VOCs were identified and quantified in trace concentrations via high-resolution real-time mass-spectrometry, starting from a menstruation and then repeated follow-up with six intervals including the next bleeding. Repeated measurements within biologically comparable groups were employed under optimized measurement setup. We observed pronounced and substance specific changes in exhaled VOC concentrations throughout all cycles with low intra-individual variations. Certain blood-borne volatiles changed significantly during follicular and luteal phases. Most prominent changes in endogenous VOCs were observed at the ovulation phase with respect to initial menstruation. Here, the absolute median abundances of alveolar ammonia, acetone, isoprene and dimethyl sulphide changed significantly (P-value ≤ 0.005) by 18.22↓, 13.41↓, 18.02↑ and 9.40↓%, respectively. These VOCs behaved in contrast under the presence of combined oral contraception; e.g. isoprene decreased significantly by 30.25↓%. All changes returned to initial range once the second bleeding phase was repeated. Changes in exogenous benzene, isopropanol, limonene etc. and smoking related furan, acetonitrile and orally originated hydrogen sulphide were rather nonspecific and mainly exposure dependent. Our observations could apprehend a number of known/pre-investigated metabolic effects induced by monthly endocrine regulations. Potential in vivo origins (e.g. metabolic processes) of VOCs are crucial to realize such effects. Despite ubiquitous confounders, we demonstrated the true strength of volatolomics for metabolic monitoring of menstrual cycle and contraceptives. These outcomes may warrant further studies in this direction to enhance our fundamental and clinical understanding on menstrual metabolomics and endocrinology. Counter-effects of contraception can be deployed for future noninvasive assessment of birth control pills. Our findings could be translated toward metabolomics of pregnancy, menopause and post-menopausal complications via breath analysis.

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1

Heat-map of exhaled end-tidal abundances of 13 selected VOCs in 24 young and healthy women throughout six different phases of the menstrual cycle (menstrual bleeding – 2nd menstrual bleeding). Medians of normalized values over 60 s of breathing are displayed for each participant during the different cycle phases (located as the central X-axis). VOC data were normalized (for each participant) onto corresponding abundances in the third breath of the second minute from the initial menstrual bleeding phase (see method section). Red, green and blue colors represent relatively high, medium and low concentrations, respectively. The upper heat-map represents the data from the contraception cohort (P-13–P-24) and the lower heat-map represents the data from the control group (P-1–P-12). Isoprene was not exhaled by P-16 and P-21 (contraception cohort) and was thus assigned to ‘0’ values in all measurement points. Qualitative regulations of two main female sex hormones are placed at the top (of contraception cohort) and bottom (of control cohort) along the x-axis. Red and violet lines represent estrogen and progesterone hormones, respectively. The vertical green line represents the onset of the ovulation phase and separates the follicular and luteal phases.

Figure 2

Comparisons of four endogenous VOCs from all women, control- and contraception cohort. Y-axes represent median signal intensities of exhaled endogenous VOCs. X-axes represent the six different measurement points (i.e. different menstrual cycle phases from first menstrual bleeding to 2nd menstrual bleeding) corresponding to the time course of the study. VOC data of all phases were compared to the corresponding median values in the initial ‘menstrual bleeding (MB)’ phase. The ‘*’ symbols (red and green colored) represent the statistically significant (i.e. P-value ≤ 0.005) differences in relation to the initial MB phase. A green ‘*’ is used to assign significant changes at the ovulation phase.