Menstrual cycle higher level of substance abuse is due to decreased self-control as a result of the higher metabolic demands during the luteal phase. Infrequent or irregular ovulation is called "oligoovulation". The absence of ovulation is called "anovulation". Normal menstrual flow can occur without ovulation preceding it: an anovulatory cycle. In some cycles, follicular development may start but not be completed; nevertheless, estrogens will be formed and stimulate the uterine lining. Anovulatory flow resulting from a very thick endometrium caused by prolonged, continued high estrogen levels is called "estrogen breakthrough bleeding". Anovulatory bleeding triggered by a sudden drop in estrogen levels is
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