Semen Analysis
Alex Tatem, MD
What is Male Infertility?
If you’re struggling to conceive, you aren’t alone. Approximately 15% of couples will have trouble achieving pregnancy at some point in their lives. Typically defined as the inability to achieve pregnancy after 12 months of unprotected intercourse, the diagnosis of infertility can be devastating to a couple.
Although most think of fertility as primarily a female issue, the truth is that infertility is the result of a complex interplay of both male and female factors and roughly 50% of couples struggling with infertility will have some sort of contributing male factor. Fortunately, there’s hope. Almost every cause of male infertility can be treated.
We are dedicated to the study and treatment of male reproduction and infertility. It is our sincere hope that the following articles can serve as a resource to patients and couples seeking to better understand male factor infertility as they continue on their journey to build their family.
What is a Semen Analysis?
The evaluation of potential male factor infertility should begin with a comprehensive clinical and laboratory evaluation by a reproductive urologist with specialty training in male infertility. Although there are many specialized lab tests for male fertility and testicular function, the semen analysis is considered to be a key test in the evaluation of male fertility.
Some Basics
When a man ejaculates, the resulting fluid is called semen. This fluid contains sperm from the testicles, but also specialized proteins and chemicals secreted by organs known as the prostate and seminal vesicles that protect sperm and facilitate their function. A semen analysis is a comprehensive evaluation of both the sperm themselves and their surrounding fluid. There are several key components to this including: 1) volume, 2) sperm concentration, 3) motility, and 4) morphology.
Volume
After allowing the sample to incubate and liquify for approximately 20 minutes, the semen is placed into a measuring cylinder and is evaluated for its total volume in milliliters (mL). In 2010 the World Health Organization (WHO) released their 5th edition guidelines for semen analysis reference ranges stating that anything greater than 1.5 mL is considered normal.
Common causes for low ejaculate volume include incomplete collection (if some of the ejaculate falls outside of the collection cup) or a blockage somewhere along the internal tubing where ejaculate is carried.
Sperm Concentration
Once the semen volume has been measured, a predetermined amount is placed on a specialized platform known as a standardized count chamber and examined under a microscope by a trained technician. All moving (motile) and non-moving (non-motile) sperm are counted. The number of sperm observed in this fixed amount of fluid allows determination of man’s sperm concentration. The WHO 5th edition minimum value for sperm concentration is > 15 million sperm per mL of fluid.
Low sperm concentration (also known as oligospermia) can be the result of many different factors, including toxin exposure, testicular failure, genetic problems, hormone abnormalities, varicoceles, and prior injury.
Motility
Another critical aspect of sperm function is sperm motility. While being examined under the microscope, sperm are assessed to see if they are swimming and, if so, how well. This results in a percent motility and a percent progressive motility. The WHO 5th edition lower limits of normal for these values are >40% and >32%, respectively.
Causes of poor sperm motility (also known as asthenospermia) include varicoceles, hormone abnormalities, vitamin deficiency or intrinsic problems with sperm anatomy.
Morphology
Sperm morphology is a quantitative evaluation of the number of ‘ideal’ looking sperm in the semen specimen as defined by a set of very strict criteria. The vast majority of sperm rarely look perfect however, and as a result the normal range for sperm morphology is only >4%. That means that only 4 out of every 100 sperm can look ‘normal’ and that’s still within the acceptable limits of the test. Put another way, the typical man may have 95% of their sperm which do not look perfect under the microscope.
Studies have shown that even men with ‘abnormally’ shaped sperm (called teratospermia) can still achieve fatherhood at rates similar to that of men with ‘normal’ sperm. As a result, sperm morphology is one of the more challenging aspects of the semen analysis and its significance should be discussed with a reproductive urologist with expertise. It is important to understand that morphology is not an indication that a child will have a birth defect or that a form of invasive treatment is needed.
Other Factors
There are many other values that are frequently tested during semen analysis. These include viscosity (semen thickness), pH (relative acidity), and the presence or absence of fructose. These values can offer minimal additional insight into a man’s fertility.
Getting Tested
It’s important to know that semen analysis results can be highly variable, even when collected from the same patient on different days. That’s why it’s important for men to submit at least two different samples when undergoing a fertility evaluation. These samples should be given with exactly 2-7 days of abstinence prior to each evaluation. This is a critical point that men should be aware of when planning to see their physician or submit a specimen. Less than 2 days of abstinence can result in falsely lowered sperm counts while greater than 7 days can result in decreased sperm motility.
Specimens are ideally collected by masturbation without lubrication as this can significantly affect results. For patients that are uncomfortable providing a specimen at their lab or physician’s office, it’s sometimes possible to arrange collection at home as long as the specimen can be brought in within the hour. Although there are more and more ‘at-home’ semen analysis tests being advertised for men questioning their fertility, we do not recommend these as they are much less accurate than a formal laboratory semen analysis.
Parting Thoughts
Even if you’re a patient with less than ideal semen analysis parameters, there’s still hope for you. Many of these values can be improved or even normalized with appropriate treatment! What’s important is that you seek out a comprehensive evaluation from a reproductive urologist with expertise in male fertility. If you have any more questions about semen analysis or male fertility, please feel free to reach out using the contact number in the link at the top of the page to find a male fertility expert in your area.