Elevated scrotal temperature as major cause of male infertility
Prof. Oladapo Ashiru
The Fertility and Sterility Journal published the most current definition of infertility in its September 2017 edition. It defined infertility as a “disease characterised by the failure to establish a clinical pregnancy after 12 months of regular and unprotected sexual intercourse or due to an impairment of a person’s capacity to reproduce either as an individual or with his/her partner.”
Fertility interventions, it added, may be initiated in less than one year, based on medical, sexual and reproductive history, age, physical findings and diagnostic testing.
The publication also described infertility as a disease, which generates disability as an impairment of function.
The new definition was arrived at a meeting held by 50 experts on fertility in Geneva and it will be adopted by the World Health Organisation.
This definition underscores the fact that male and female partners are responsible. Furthermore, the responsibility as regards the causes of infertility is 50 per cent in the male and 50 per cent by the female partner.
Causes of infertility
In sub-Saharan Africa, the prevalence of infertility has been notably variable, ranging from 20 to 46 per cent. About 30 per cent of infertility is due to female problems, 30 per cent to male issues and 30 per cent to combined male/female issues, while in 10 per cent there is no recognisable cause.
In Nigeria, the prevalence is between 20 and 25 per cent among married couples.
The causes of infertility have been divided into two main categories: Male infertility, which is principally due to reduced semen parameters and Female infertility, which is due to factors, such as occlusions of fallopian tubes, uterine or endometrial abnormalities, abnormal cervix and anovulation in the female partner.
The primary cause of male infertility is poor sperm count and concentration, poor motility and morphology or a combination of the above. Factors that can lead to male infertility include exposure to heat for prolonged periods, especially the scrotal region; exposure to radiation, environmental pollutants, genetic abnormalities, heavy use of alcohol, smoking, etc.
Latest studies have shown that elevated scrotal temperature is a major cause of male infertility as mentioned above. It is known that testicular function is temperature dependent and it requires a temperature of 2 degrees Celsius to 4 degrees Celsius below core body temperature, which is why the scrotal sac is situated outside of the body.
Scrotal hyperthermia is a well-documented mechanism of abnormal spermatogenesis associated with male infertility, thus maintaining a temperature difference between the body and scrotal sac is crucial to ensure the production of normal spermatozoa.
Modern technology has not been kind to the male reproductive system and it has been linked to having a significant impact on raised scrotal temperature, such as the use of laptops on the lap, EMF from cell phones positioned to close the scrotum, prolonged car driving and sports cars, heated car seats, tight clothing, and others.
Causes of elevated scrotal temperature
The Laptop Computer is an active heat-generating device that exposes the scrotum to the dissipated high internal operating temperature. A working LC in a laptop position causes significant scrotal temperature elevation by a direct heating effect of the LC and also by the dependent sitting position, with closely approximated thighs, that is necessary to balance a LC on the lap.
Balancing laptop computers on the lap has been found to raise the scrotum’s temperature to around a 5 degrees Fahrenheit increase (or about 2.7 degrees Celsius) and it has been shown that sperm concentration and motility dropped by 40 per cent when median daytime scrotal temperature rose by 1 to 2 degrees Fahrenheit (or 1 degree Celsius).
Electromagnetic waves from cellphones
The frequency of incoming waves and subsequent energy of transmitted waves by the cell phone device can have an effect on not only the general body but also more specifically on the male reproductive system. This EMF has a detrimental impact on the motility and characteristics of spermatozoa, leading to a significant decrease in the percentage of forward progressive motile sperm. Also there is a substantial increase in the rate of mitochondrial ROS production and the level of 8- OHdG (Reactive oxygen species, and free radicals that can alter the DNA and genetic composition of cells). It was concluded that RF-EMW emitted from cell phones may increase oxidative stress in human spermatozoa leading to decreased motility and viability characteristics.
Studies showed that for heavy users of cell phones, sperm counts were 30 per cent lower than men who did not use a cell phone.
Therefore, exposure to cell phones may be correlated with the significant decrease of melatonin in the body, making spermatozoa more susceptible to reactive oxygen species attack. Thus, the effect of cell phone EMW on the generation of oxidative stress cannot be ignored. The consequence of such ignorance may be dismal in regards to male infertility and possible cancer in the future. That is why most mobile phones are sold with an earpiece.
Heated surfaces and sport cars
Heat from the front engine surface or heated car seat (especially sports cars due to the closeness to the front engine) further adds to scrotal temperatures that are already elevated from being in a seated position.
Professional sports car drivers or occupational drivers and individuals who have long daily commutes are more prone to having increased scrotal temperatures, poorer sperm quality and longer time to achieve pregnancy. The adverse effect of long hours of driving and seated commuters increases in severity with the number of years spent engaging in such activities.
Although the effect of tight underwear versus boxer shorts on sperm parameters is inconclusive, it would seem that tighter-fitting undergarments would leave less room for scrotal movement and air circulation hence contributing to higher genital temperatures and in turn lead to increase in scrotal temperature. That being said, a choice of clothing that encourages good air flow could minimize the deviation of physiological scrotal temperatures.
Hot bath and sauna
The use of hot baths and sauna for relaxation and rejuvenation may make one feel better, but it also hurts semen quality. Full-body immersion in a warm bath, hot tub, heated Jacuzzi or whirlpool at temperatures over 36.9°C for 30 min or more a week for three months or more leads to wet hyperthermia, which could have a reversible negative effect on sperm motility. Users of conventional saunas experience moist heat and warmed surfaces, whereas modern infrared-type saunas offer dry, radiant heat.
Studies show that after sauna exposure, scrotal temperatures reach up to body temperatures within 10 minutes, and there is a significant but reversible negative effect on spermatogenesis. At temperatures ranging from 80 to 90°C, and at different frequency and duration of exposure, the use of saunas could disrupt spermatogenesis and cause abnormal sperm count and motility. Usually a cold ice towel are provided outside the sauna and steam to cool down.
Occupational or residential heat exposure
Another factor that may contribute to heat stress in the male is ambient heat caused by hotter environmental temperatures where a man lives or works. Specific labour intensive jobs entail exposure to long periods of extreme, radiant heat. Welders, for example, are exposed to extraordinary levels of heat, toxic metals and fumes during welding. Studies involving these workers demonstrate a reversible decline in semen quality.
Those working directly with sources of severe weather, such as bakers and ceramic oven operators, have a longer time to pregnancy, which suggests that occupational heat exposure has an effect on fertility. Men who work in close range to sources of intense heat, such as the rear end of a submarine (location of the motor) seem to face infertility-related problems.
Credit: The Punch