Pre-ejaculate

Pre-ejaculate (also known as pre-ejaculatory fluid, preseminal fluid, or Cowper's fluid, and colloquially as pre-cum) is the clear, colorless, viscous fluid that emits from the urethra of a man's penis when he is sexually aroused. It is similar in composition to semen, but has some significant chemical differences. Among men with certain infectious diseases, pre-ejaculate can often contain disease pathogens. The presence of sperm in the fluid appears to be rare. Pre-ejaculate is believed to function as a lubricant and an acid neutralizer. The amount of pre-ejaculate emitted varies widely between individual men.

Origin and composition
The fluid is discharged during arousal, masturbation, foreplay or at an early stage during sex, some time before the man fully reaches orgasm and semen is ejaculated. It is primarily produced by the bulbourethral glands (Cowper's glands), with the glands of Littre (the mucus-secreting urethral glands) also contributing.

The amount of fluid that the human male issues varies widely among individuals. Some men do not produce any pre-ejaculate fluid, while others emit as much as 5 ml.

Pre-ejaculate contains some chemicals associated with semen, such as acid phosphatase. Some semen markers, such as gamma-glutamyltransferase, are completely absent from pre-ejaculate fluid.

Function
Acidic environments are hostile to sperm. Pre-ejaculate neutralizes residual acidity in the urethra caused by urine, creating a more favorable environment for the passage of sperm. The vagina is normally acidic, so the deposit of pre-ejaculate before the emission of semen may change the vaginal environment to promote sperm survival.

Pre-ejaculate also acts as a lubricant during sexual activity, and plays a role in semen coagulation.

Risks
Studies have demonstrated the presence of HIV in most pre-ejaculate samples from infected men. Infection with HIV can lead to acquired immunodeficiency syndrome (AIDS).

Many also express concern that pre-ejaculate may contain sperm which can cause pregnancy, using this to argue against the use of coitus interruptus (withdrawal) as a contraceptive method. However some studies have found that withdrawal could be almost as effective as condoms in preventing pregnancy. This being in direct contradiction to conventional wisdom, however, careful research and consideration should be used before using withdrawal as a contraceptive practice. There have been several studies that conclude no sperm is present and thus pre-ejaculate is ineffectual at causing pregnancy. It is likely, however, that pre-ejaculate which follows a recent ejaculation will contain sperm, as some ejaculate is always left in the duct after orgasm.

Overproduction
In rare cases, a man may produce an excessive amount of pre-ejaculate fluid that can be a cause of embarrassment or irritation. A few case reports have indicated satisfactory results when such men are treated with a 5-alpha-reductase inhibitor.

In such cases, one doctor recommended considering the differential diagnosis of prostatorrhea, the emission of prostatic secretions during straining associated with urination or defecation.

Religious attitudes
In Islam, after the emission of pre-ejaculate fluid, ritual purification is recommended, by washing the affected areas (including clothing) by water. However, it does not require Ghusl, unlike the semen which comes after the ejaculation. Having a pre-ejaculate fluid which came out of the penis has the same effect as doing excretion. In other words it is considered as a hygienic issue more than a sexual issue. For many other religions, pre-ejaculate is not of significance.