What Is a Semen Analysis?
A semen analysis is usually the first male fertility evaluation we do in the fertility assessment process. Getting a semen analysis may seem intimidating for many men and their partners, but there’s no need to feel embarrassed. Male infertility is a common condition affecting one in 10 men.
In fact, up to one in 20 men have no sperm at all in their ejaculate. Even if you have no sperm in your ejaculate, this doesn’t mean you’ll never be able to have a child. We can help up to 70 percent of men who have no sperm in their ejaculate have children.
The factors we look at in a semen analysis are:
- sperm concentration,
- percentage of sperm that are motile—or able to swim, and
- sperm morphology (shape).
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Semen Analysis Terms
Many patients find it helpful to read brief definitions of semen analysis terms:
Asthenospermia means that the sperm have poor motility—or do not swim well.
Azoo means an absence of any sperm.
Oligo means having fewer than normal sperm.
Pyospermia refers to a condition where there are many, many white blood cells in the sperm, usually from the prostate. So, azoospermia means no sperm, and oligospermia means a total motile count of fewer than 20 million. Severe oligospermia is defined as fewer than one million motile sperm. To make all of these conditions even more complicated, any of these prefixes can be used in combination with each other.
Teratozoospermia refers to abnormally shaped sperm.
Zona pellucida is the egg coating.
Interpreting Your Semen Analysis
How your specialist interprets the results can vary from lab to lab, because there are many methods for evaluating sperm. The most important point to keep in mind is that the amount of semen you have in your ejaculate naturally goes up and down. Semen analyses vary day-to-day, week-to-week, and year-to-year.
For example, sperm total motile counts (TMC) vary widely from two to 200 million over the course of a year. Researchers don’t know exactly what causes these variations. This is the reason that we ask all of our patients to get at least two semen analyses. (See table 1.)
If we confirm that the findings are abnormal, we will recommend that you see a doctor to evaluate your genital tract for any anomalies as well as hormonal abnormalities. Most men with an abnormal semen analysis can father children with treatment.
What Do Doctors Look for in a Semen Analysis?
The data generated from a semen analysis can seem very confusing at first. It is a very unique test and one of the few laboratory tests that still relies on a human or a computer to count the number, motility, and morphology (shape) of sperm cells under a microscope. We measure the volume of sperm in milliliters (ml).
Sperm Motility: The Total Motile Count
Perhaps the most important part of a semen analysis is the total motile count or TMC. The total motile count is the number of sperm that are motile (sperm that swim) in the ejaculate.
What Is a Normal Sperm Motility?
A total motile count of over 20 million is considered normal. However, even if you have more than 20 million motile sperm, it may not result a higher chance of pregnancy.
If you have fewer than 20 million motile sperm, your chances of having a successful pregnancy go down. We can use sperm with a total motile count of over five million for intrauterine insemination (IUI) of sperm or in-vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI).
| Standard Test | Normal Value |
|---|---|
| Volume | 2.0 mL or greater |
| Sperm Count | 40,000,000 or more |
| Sperm Concentration | 20,000,000 or more/mL |
| Total Motility | 40% or more |
| Total Progressive Motility | 32% or more |
| Morphology (% of normal-appearing sperm) | 4% or more normal |
Table 1: Normal semen analysis test results
Volume, Count, Motility, & Morphology
Volume: What was the volume of ejaculate?
Humans produce semen in relatively small amounts. While we include a normal range for volume, for an abnormal range we don’t know if it causes infertility.
Too little or too much semen, however, may interfere with how semen enters the female reproductive tract during intercourse. Most frequently, a small volume of semen means that there is not enough semen or an obstruction in one or more ducts that give fluid to semen.
Count: How many sperm per milliliter were there?
We measure sperm count by ml, both total count and how concentrated they are. If the sperm count is lower, we assume that this is responsible for the infertility. This is not a perfect assumption, as there are men with low counts who have children.
Low sperm counts can also be due to anatomical or hormonal issues. Many, however, we can’t explain.
Motility: How many moving sperm are present?
Some labs will rate the ability of the sperm to move (motility quality) by a grading system. Grading systems, however, don’t always present the whole picture. An important value we consider is the percent of sperm that can move with forward, or progressive, motility.
Some causes of low motility can include:
- varicoceles (varicose veins),
- infection, and
- sperm antibodies.
Some men with high sperm counts and but lower sperm motility may still have normal amounts of moving sperm.
Morphology: What percentage of sperm are normally shaped?
Normally shaped sperm have the best chance of fertilizing an oocyte, or immature egg cell. For procedures like IVF (in vitro fertilization) and/or ICSI (intra-cytoplasmic sperm injection), a morphology evaluation (study of the sperm shape) helps us create procedures more likely to succeed.
A morphology evaluation may show the presence of abnormally shaped sperm in a semen sample. However, these abnormal sperm may not affect fertility, especially if the total sperm count is normal AND only a small percentage of the sperm are abnormally shaped.
Improving some of these factors, such as an abnormal hormone profile or repairing a varicocele, can improve sperm morphology.
