Nocturnal clitoral tumescence (NCT), colloquially known as morning bean, is a spontaneous swelling of the clitoris during sleep or when waking up. Similar to the process in males,

nocturnal penile tumescence Nocturnal penile tumescence is a spontaneous erection of the penis during sleep or when waking up. Along with nocturnal clitoral tumescence, it is also known as sleep-related erection, morning glory or morning wood. Men without physiological erec ...

, females experience clitoris tumescence or engorgement of the

vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...

mainly during

REM sleep Rapid eye movement sleep (REM sleep or REMS) is a unique phase of sleep in mammals and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream viv ...

phase. According to Fisher et al., the increase in vaginal blood flow associated with NCT during REM sleep is similar to the process in men in frequency, i.e. 95% of REM phases. It does occur a bit more often in non-REM sleep, and each episode appears shorter in duration. In terms of magnitude, NCT is similar to that induced by erotic stimulation when awake. The phenomenon was first documented in 1970 by Karacan et al.,Karacan, I, Rosenbloom, AL and Williams, RL (1970) The clitoral erection cycle during sleep. ''Sleep Res.'', 7:338 with a single aforementioned follow-up study in 1983 by Fisher et al.

References

Sleep Clitoris Sexual arousal {{Anatomy-stub

See also

References