Vaginal lubrication

Vaginal lubrication is the naturally produced lubricating fluid that reduces friction during sexual intercourse. It is typically produced with women's sexual arousal, but also can be produced when there is no arousal. While plasma seepage from vaginal walls due to vascular engorgement is considered to be the chief lubrication source, the Bartholin's glands, located slightly below and to the left and right of the introitus (opening of the vagina), also secrete mucus to augment vaginal-wall secretions.

Vaginal dryness is the condition in which this lubrication is insufficient.

Composition
The lubrication fluid contains water, pyridine, squalene, urea, acetic acid, lactic acid, complex alcohols and glycols, ketones, and aldehydes. The fluid is typically clear and more resembling of male pre-ejaculate than male ejaculate. It can vary in consistency, texture, taste, color, and odor, depending on sexual arousal, the phase of the menstrual cycle, the presence of an infection, certain drugs (legal or illegal), genetic factors, and diet.

Vaginal fluid is slightly acidic and can become more acidic with certain sexually transmitted diseases. The normal pH of vaginal fluid is between 3.8 and 4.5, whereas male semen is typically between 7.2 and 8.0 (a neutral substance has a pH of 7.0).

Changes in vaginal lubrication
Certain medications, including some over-the-counter antihistamines, as well as life events such as pregnancy, lactation, menopause, aging or diseases such as diabetes, will inhibit lubrication. Medicines with anticholinergic or sympathomimetic effects will dry out the mucosal or "wet" tissues of the vagina. Such medicines include many common drugs for allergic, cardiovascular, psychiatric, and other medical conditions. Oral contraceptives may also increase or decrease vaginal lubrication.

Women report that they are significantly more likely to experience vaginal dryness during sexual intercourse with circumcised men than with genitally intact men. .

Role in disease prevention
Safe sex educators warn that cultural practices involving the drying of the vagina with leaves and other natural materials may be linked to the transmission of STDs.

Artificial lubrication
When natural lubrication is insufficient, penetrative intercourse may be uncomfortable or painful. A personal lubricant applied to the vaginal opening and/or the penis can prevent this discomfort. More rarely, a vaginal suppository may be inserted prior to intercourse.

Oil-based lubricants can weaken latex and reduce the effectiveness of condoms, latex gloves, or dental dams as either forms of birth control or for protection from sexually transmitted diseases, so water- or silicone-based lubricants are often used instead.

Removal of lubrication
Some women use products to remove the lubrication, so that they can have dry sex. The process of deliberately drying the vagina is a common precursor to sex in sub-Saharan Africa. The goal of this removal of lubrication is to make the vagina dry and tight, supposedly to increase sexual pleasure for the man. However, these practices make sex very painful for the woman. Dry sex is common in Sub-Saharan Africa and is of concern as it increases the chances of transmitting sexually transmitted diseases (STDs) such as HIV for both partners. The lack of lubrication required for dry sex causes lacerations in the delicate tissue of the vagina, increasing the risk of HIV transmission.