Menstrual cycle shortest and longest cycle lengths is considered very irregular. The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39. Subsequently, the variability increases slightly for women aged 40 to 44. The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14.13 days, standard deviation 1.41 days) whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).
Menstrual cycle by women during the peak of their fertility in the menstrual cycle. Moreover, women may demonstrate preference for men with a scent that indicates developmental stability. With regard to women's smell across the cycle, some evidence indicates that men use olfactory cues in order to know if a woman is ovulating. Using a rating of women's odors, women who are ovulating have been rated as more attractive by men. Men demonstrate preferences for the scent of fertile women. Preferences for facial features in mates can also change across the cycle. There has been no difference found in preference for long-term