Semen Hyper-viscosity: a cause of infertility


Semen hyper-viscosity (SHV) is a condition that can impair the physical and chemical characteristics of seminal fluid, and can cause infertility.

The prevalence of SHV is between 12-29 % and may have a negative impact on sperm motility and contribute to a poor outcome in both natural and assisted conception

At ejaculation, human semen immediately forms a solid gel-like coagulum. The clot liquefies spontaneously and completely within 30 min. Liquefaction occurs both in vitro and in vivo after deposition in the vagina. After liquefaction, the ejaculate results in a liquid with varying degrees of viscosity or consistency.

Hyper-viscosity is not an uncommon finding, but the cause of abnormally residual viscosity of semen after it has coagulated and then liquefied is still unknown. Coagulation of the seminal plasma is a characteristic of the function of human seminal vesicles, whereas the liquefying factors originate in the prostate. If the consistency or viscosity of the semen after liquefaction is dependent on the interactions of secretions of both the seminal vesicles and prostate, then hyper-viscosity may be a consequence of alterations in the function of the male sex accessory glands. In particular, hyper-viscosity of semen samples is associated with hypo-function of the seminal vesicles.

However, Infection and high levels of seminal leukocytes may also result in the development of SHV. Oxidative stress and biochemical and genetic factors can furthermore contribute to this condition. Hyper-viscosity can impair normal sperm movement in the female reproductive tract and can lead to decreased sperm count.

SHV is treated with mucolytic enzymes, antibiotics and anti-inflammatory agents in certain cases. Further research is needed to better understand the contributors to SHV and the treatments that can be used for infertile males with hyperviscous semen.