Vaginal lubrication is a natural function of the vagina, the female sexual organ. Its purpose is to prevent irritation of the vaginal tissue, especially during sexual intercourse. Consequently, it often occurs early in the sexual process and is seen as an indicator of sexual arousal. Numerous factors can affect lubrication, including emotional states, food or drug intake, and aging. These result from changes in the body’s production of estrogen, the female sex hormone.
The vagina is lined with a layer of specialized tissue similar to epidermis, or skin. This tissue, called the vaginal epithelium, allows the passage of naturally occurring moisture. An imperceptible amount of moisture may be present at all times to prevent the epithelium from chafing during normal movement and activity. When sexual arousal occurs, blood flow to the genitals is increased, with a resulting increase in vaginal lubrication. During intercourse, this lubrication protects the epithelium from lacerations or other damage that could result from intense friction.
Visual or emotional stimuli can normally cause arousal and increase vaginal lubrication, even if actual intercourse does not occur. Regardless of the circumstances, the increase of blood flow to the genitals will cause lubrication. The resulting fluid originates in locations throughout the vagina and is composed of a variety of naturally formed acids, alcohols, and enzymes. The actual composition of the lubricating fluid varies from woman to woman. Depending on the circumstances, this process may not be apparent to anyone else and sometimes may even come as a surprise to the woman herself.
The process of vaginal lubrication is related to estrogen production, which is itself constantly changing. Thus, lubrication can be affected by anything that reduces estrogen, such as some birth-control pills or the effects of pregnancy and breastfeeding. Other factors that can affect estrogen production include menstruation, a woman’s percentage of body fat, and even genetic factors. Younger women tend to produce more estrogen naturally, with a corresponding effect on lubrication, although this varies by the individual. Age and menopause, conversely, can reduce the amount of lubrication.
External stimuli of various kinds can also cause changes in the rate of vaginal lubrication. Emotional states like anxiety, nervousness, or stress can have a detrimental effect, just as they can on other body processes. The properties of antihistamines that reduce the production of mucus and other bodily fluids can also affect lubrication. Other drugs and certain foods can also reduce vaginal lubrication, as well as environmental factors, including bathing in warm water. Many women and couples employ artificial lubricants for occasions when natural lubrication is not sufficient.