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Understanding Semen Analysis

There seems to be a little bit of misunderstanding with some of my patients when it comes to interpreting the results of a semen analysis. Looking at the final number and thinking that everything is OK could be misleading. It’s important to understand how that final number was calculated so that the expectations are set correctly.




Introduction

You would think that when a man ejaculates the ejaculate, or semen, contains hundreds of millions of well-shaped sperm that swim very fast in a straight line. Unfortunately, because of many factors that we will cover later, this is rarely the case. Let’s try to interpret the 3 most important parameters being measured in a semen analysis.

 

Volume

This is typically the first number on a semen analysis report and it has to do with the amount of seminal fluid (semen) in the sample. It is important to understand that semen does not equate to sperm. The seminal fluid is a mix of different fluids from different glands; prostate glands, urethral glands, and seminal vesicles. Sperm is only 10% of  semen volume. Measured in milliliters (mL), the volume can change depending on when the man last ejaculated. For example, the volume of a man who has abstained from ejaculating for 2 days will be less than if the same man abstains 5 days from ejaculating . According to the sixth edition of the WHO Manual for Human Semen Analysis, which was published in July of 2021, it is considered normal if a man has a volume between 1.3 and 1.5mL. Since the volume is multiplied by concentration and motility, the volume plays a big part in the final number.


Concentration

This is the number of sperm per mL in a semen sample. This is not the total amount of sperm in the semen sample, but rather the number of sperm per mL. In order to get the total number of sperm in the sample, the volume, or how many mL of semen are in the sample,  needs to be multiplied by the concentration, or how many sperm can be found per mL. For example, if a man has a volume of 2.5mL and a concentration of 100 million sperm per mL, his sperm count would be 250 million sperm. This very big number doesn’t tell us anything about how healthy the sperm are nor if  they are capable of swimming forward. So, this is still not the final number.


Motility

This is perhaps the most important number in the entire semen analysis, as it is the number of sperm that are moving. This number is represented as a percentage – moving versus nonmoving sperm. Unfortunately, as long as the sperm is moving it counts as a motile sperm – even if the sperm is twitching or swimming around in circles. A sperm without a forward progression is not going to help the woman get pregnant. For this reason some labs use another metric, the progressive motility, to identify how many sperm are swimming forward. Some labs instead of having a progressive motility category  have a grading system to grade how well sperm are swimming. For example, a grade 0 or D indicates no motility, grade 1 or C indicates minimal forward progression, a grade 2 or B indicates decent sperm activity, and grade 3 or A indicates strong sperm activity with forward progression.


The total motile count, also seen in lab reports as TMC, is the product of Volume multiplied by Concentration multiplied by Motility – ideally progressive motility. Let’s assume that in the previous example the man had a motility of 43%. In that case we would multiply 250 million by 43% and we would get a TMC of 107.5 million motile sperm. This is the number that we need to be concerned with.



Sperm Production

Unlike women, who are born with a fixed number of eggs, men produce sperm 24 hours a day at an average of 125 million sperm per day. Like women, whose eggs take between 90 to 120 days to mature and be released during ovulation, men’s sperm take roughly the same amount of time to reach maturity and to be ready to be ejaculated. Because men are constantly producing sperm it is relatively easy to improve sperm quality. However, it is important to understand that once a man decides to make the necessary lifestyle changes to improve his sperm quality, it could take around 120 days before seeing any changes in sperm quality.

 

What Could Damage Sperm

Temperature

The testicles are located outside the body for a reason. The ideal sperm production occurs at around 93.2 degrees Fahrenheit. This is about 5 degrees cooler than the normal body temperature of 98.6 degrees. Anything that raises the temperature of the testicles can be detrimental to sperm production and quality. Some studies show that an increase in scrotal temperature of 1°C is sufficient to suppress spermatogenesis. Other studies show that a higher testicular or scrotal temperature elevation between 1 and 2.9°C was more consistently associated with a sustained and considerable negative effect on spermatogenesis and fertility.


Some of the most common sources of raising sperm temperature are:

Hot Tubs and Saunas:

A study published in 2007 showed that men using hot tubs with a temperature above 98.4 degrees for 30 minutes per week for 3 months were found to have 22% lower sperm motility than those that didn’t use a hot tub. The average hot tub temperature falls between 97 to 104 degrees. If a man uses a hot tub on a daily basis his sperm quality will drop significantly. Saunas are definitely bad for sperm quality and they should be avoided in men who are having difficulties conceiving. A study published in 2013 showed men using saunas had decreased semen parameters.


Tight underwear:

Wearing tight underwear can also damage sperm quality and production. A study published in 2018 found that men who wore boxers had a sperm count 25% higher than those that wore tighter underwear.


Laptop:

 A study published by Human Reproduction titled “Increase in scrotal temperature in laptop computer users”  looked at men using laptop computers resting on their laps for 60 minutes and found a 2.8 degree (C) increase compared to their baseline. The study concluded by saying that:

Our study demonstrates statistically significant elevation of scrotal temperature in laptop computer users.

Lifestyle

Smoking:

The relationship between cigarette smoking and infertility has been studied for decades. A cross-sectional analysis of 2,542 healthy men found that on semen analysis, cigarette smokers had lower semen volumes, sperm counts, and percentage of motile sperm compared to men who did not smoke.


Diet:

A lot of research has been done regarding the effect of animal protein and human health. In addition there’s plenty of evidence that animal protein negatively affects sperm quality. An abstract presented by Harvard at the American Society for Reproductive Medicine’s annual conference where researchers analyzed 364 samples of semen from 156 men who were having reproductive difficulties concluded that those participants with higher intakes of processed meat products (more than one-third of a serving per day) saw more abnormalities in sperm count, size, and shape, compared with men who ate less.


In addition, Harvard University released a study titled “Dairy food intake in relation to semen quality and reproductive hormone levels among physically active young men” where they concluded that:

Total dairy food intake was inversely related to sperm morphology.

How To Improve Sperm Quality

The first step in improving sperm quality is to stop doing the things that we know are damaging to sperm. The second step is to start incorporating some of the things that are known to improve sperm quality.


Plant-based diet:

Due to the large amount of convincing evidence regarding the negative effect of animal protein and human health, more and more studies regarding a plant-based diet are appearing. For example, in 2021  the Journal of Human Reproductive Sciences published a study titled: “Impact of the Vegan Diet on Sperm Quality and Sperm Oxidative Stress Values”. The study looked at the sperm quality of vegan diet men (strictly vegetable diet with no animal products) and compared them with non-vegans (no diet restrictions) and concluded that:

Results obtained in this study provide additional evidence about the favorable effect of a plant-based diet on sperm parameters.

Contrary to some literature, not based on randomized controlled trials (RCT), soy protein does not adversely affect semen quality. A randomized intervention study published by Fertility and Sterility concluded that: “Consumption of soy protein of low or high isoflavones content does not adversely affect semen quality in a sample of healthy adult men”.


Acupuncture

In China, the treatment of acupuncture for male infertility has a long history which can be traced back to the Jin Dynasty, over 2,000 years ago. Recent research has shown time after time the benefits of acupuncture on male fertility. For example, a meta-analysis published in 2014 by the Asian Journal of Andrology where a total of 4 eligible randomized controlled trials were scrutinized evaluating the effects of acupuncture on semen parameters in 500 infertile males. The study found that acupuncture treatment was associated with a significant improvement in sperm motility and sperm concentration.

 

From releasing stress to regulating the reproductive endocrine system (LH/FSH), acupuncture has been found to improve sperm quality. One mechanism that has been well-understood in improving sperm motility is the zinc to cadmium ratio. Zinc improves sperm motility whereas cadmium causes thicker semen, thereby slowing the sperm. SOD, an antioxidant which increases both sperm count and motility is also positively influenced by acupuncture.


Conclusion

When looking at a semen analysis report, it is advisable to not just look at the final number (TMC), but look at the volume, concentration and motility (ideally progressive motility). A large volume, due to several days from abstaining from sex, might give the false impression that the patient has a normal TMC. While men produce an average of 125 million sperm per day, they can easily be destroyed by exposure to heat, diet, and smoking. Lifestyle changes, supplements, and acupuncture are effective ways to increase sperm parameters.



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