Pre-ejaculate (also known as pre-ejaculatory fluid, pre-seminal fluid or Cowper's fluid, and colloquially as pre-cum) is a clear, colorless, viscous fluid that is emitted from the urethra of the penis during sexual arousal. It is similar in composition to semen but has distinct chemical differences. The presence of sperm in the fluid is variable from low to absent. Pre-ejaculate functions as a lubricant and an acid neutralizer.
Origin and composition
The fluid is discharged from the urethra of the penis during arousal, masturbation, foreplay or at an early stage during sexual intercourse, some time before the individual fully reaches orgasm and semen is ejaculated. It is primarily produced by the bulbourethral glands (Cowper's glands), with the glands of Littré (the mucus-secreting urethral glands) also contributing. The amount of fluid that is issued varies widely among individuals. Some individuals do not produce any pre-ejaculate fluid, while others emit as much as 5 ml (0.18 imp fl oz; 0.17 US fl oz).
Function and risks
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.
Low levels or no sperm exists in pre-ejaculate, although studies examined small samples of men. Two contrary studies found mixed evidence, including individual cases of a high sperm concentration. Popular belief – dating to a 1966 Masters and Johnson study – stated that pre-ejaculate may contain sperm that can cause pregnancy, which is a common basis of argument against the use of coitus interruptus (withdrawal) as a contraceptive method. However, pre-ejaculate is ineffectual at causing pregnancy.
In rare cases, an individual 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 individuals are treated with a 5-alpha-reductase inhibitor, such as finasteride.
- Chudnovsky, A.; Niederberger, C.S. (2007). "Copious Pre-Ejaculation: Small Glands—Major Headaches". Journal of Andrology. 28 (3): 374–5. doi:10.2164/jandrol.107.002576. PMID 17251594.
- Chughtai B, Sawas A, O'Malley RL, Naik RR, Ali Khan S, Pentyala S (April 2005). "A neglected gland: a review of Cowper's gland". Int. J. Androl. 28 (2): 74–7. doi:10.1111/j.1365-2605.2005.00499.x. PMID 15811067.
- Vazquez E (1997). "Is it safe to suck?". Posit Aware. 8 (4): 15. PMID 11364482.
- Zukerman Z.; Weiss D.B.; Orvieto R. (April 2003). "Short Communication: Does Preejaculatory Penile Secretion Originating from Cowper's Gland Contain Sperm?". Journal of Assisted Reproduction and Genetics. 20 (4): 157–159. doi:10.1023/A:1022933320700. PMC 3455634. PMID 12762415.
- Gohara WF (1 February 1980). "Rate of decrease of glutamyltransferase and acid phosphatase activities in the human vagina after coitus". Clinical Chemistry. 26 (2): 254–7. PMID 6101549.
- "Researchers find no sperm in pre-ejaculate fluid". Contraceptive Technology Update. 14 (10): 154–156. October 1993. PMID 12286905.
- Killick SR, Leary C, Trussell J, Guthrie KA (2011). "Sperm content of pre-ejaculatory fluid". Human Fertility. 14 (1): 48–52. doi:10.3109/14647273.2010.520798. PMC 3564677. PMID 21155689.
- Kovavisarach, E.; Lorthanawanich, S.; Muangsamran, P. (2016). "Presence of Sperm in Pre-Ejaculatory Fluid of Healthy Males". J Med Assoc Thai. 99 Suppl 2: S38–41. ISSN 0125-2208. PMID 27266214.
- Masters, W.H. (1966). Johnson, V.E. Boston, MA: Little, Brown and Company. p. 211.
- Pudney, J., Oneta, M., Mayer, K., Seage, G., Anderson, D. (1992). "Pre-ejaculatory fluid as potential vector for sexual transmission of HIV-1". Lancet. 340 (8833): 1470. doi:10.1016/0140-6736(92)92659-4. PMID 1360584.CS1 maint: uses authors parameter (link)
- Ilaria, G., Jacobs, J.L., Polsky, B. et al. (1992). "Detection of HIV-1 DNA sequences in pre-ejaculatory fluid". Lancet. 340 (8833): 1469. doi:10.1016/0140-6736(92)92658-3. PMID 1360583.CS1 maint: uses authors parameter (link)