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).
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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:
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.
