Menstrual cycle lengths of 29.5 ± 3 days ("normal cycles") are more frequent in women who have weekly coital activity than in women who do not. In order to investigate potential mechanisms controlling the association between heterosexual activity and menstrual cycle length, and in light of the nonhuman literature suggesting that a chemical signal from males could be involved, menstrual cycle lengths of nulliparous women were evaluated following regular application of axillary extract from donor males. Compared to controls receiving only blank/ethanol applications, women receiving axillary extracts for 12.5 to 14.5 weeks showed the following changes: (1) a reduced incidence in variability of cycle lengths; and (2) a reduced proportion of aberrant length cycles.
ASJC Scopus subject areas
- Endocrine and Autonomic Systems
- Behavioral Neuroscience