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 The follicular phase also seems to get significantly shorter with age (geometric mean 14.2 days in women aged 18–24 vs. 10.4 days in women aged 40–44). Some women with neurological conditions experience increased activity of their conditions at about the same time during each menstrual cycle. For example, drops in estrogen levels have been known to trigger migraines, especially when the woman who suffers migraines is also taking the birth control pill. Many women with epilepsy have more seizures in a pattern linked to the menstrual cycle; this is called "catamenial epilepsy". Different patterns seem to exist (such as seizures