Pre-ejaculate (also known as pre-ejaculatory 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.

Origin and composition

The fluid is emitted 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; the deposit of pre-ejaculate prior to the emission of semen may change the vaginal environment to promote sperm survival.

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

Risks

Studies have demonstrated the presence of HIV in pre-ejaculate, which can lead to the disease 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. There have been no large-scale studies of sperm in pre-ejaculate, but some smaller-scale studies suggest that 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

A few men are bothered by the amount of pre-ejaculate fluid they produce. One physician described a patient who was embarrassed that the fluid would "soak through his pants during kissing or other mild erotic stimulation". 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 Sunni Islam, the emission of pre-ejaculate fluid may require ritual purification. For many other religions, pre-ejaculate is not of significance.

References