The semen analysis measures a variety of parameters, but it’s most focused on three: Are you producing enough sperm (concentration) per millileter? Are the sperm normally shaped (morphology)? And can your sperm swim well enough (motility) to produce a single sperm that can fertilize an egg? If the answer to any of those questions is no, this will kick off a variety of tests or treatments, depending on what parameter looked irregular and, frankly, what type of doctor is treating you.
The semen analysis test suffers from two major weaknesses. First, there is a lot of variability in the semen samples the same man can produce, even just a few days apart. Second, there is a lot of variation between how labs read the exact same sample, especially in the more subjective parameters like motility and morphology. For this reason, it has taken the field a long to time agree upon how to interpret the semen analysis, how many times a man needs to be tested, and what to do with the results.
Possibly the most important steps in the semen analysis process begins before the sample is given. To cut down on sample variability, the man must make sure to ejaculate within five days of the test, but not within 2 days of the test. Your doctor will also likely ask you to pause drinking alcohol and caffeine, or taking some medication, as the goal here is to assess how good your sample is under the best possible conditions.
Once you provide a semen sample, it is analyzed within 60 minutes and a report is provided to your doctor.
Typically, a semen analysis needs to be performed at least twice, often with at least two weeks between sample collections, before a diagnosis can be made.
Reading the Semen Analysis
The analysis looks at all three factors listed above — concentration, motility and morphology — in determining if there is an issue affecting fertility. Maybe you have a high sperm concentration, but if none of those sperm swim, the odds of conceiving are low. Conversely, you may have a low sperm concentration, but if the sperm you do have are uncommonly likely to swim and have the appropriate shape, you might be perfectly fine. Therefore, unless the semen analysis reveals there are simply no sperm, we need to look at all the parameters together.
Typically, your doctor will want to see a sperm concentration of at least 15 - 20 million per milliliter, but the truth is that some men who have counts lower than that are able to conceive naturally. Below are the sperm concentration numbers for 1,800 men who conceived naturally, and you will notice 5% succeeded with counts of 15 million or below.
A low sperm concentration can trigger a variety of responses, depending upon what type of doctor you are seeing. A reproductive endocrinologist, who is an OBGYN and not trained extensively in the male anatomy, will likely insist you undergo IVF and use ICSI to help fertilize the egg. A urologist, who is trained in male anatomy, will likely consider whether there is an underlying condition, such as varicocele or a hormone imbalance, that could be interfering with sperm production. Urologists will almost always prefer to address the underlying condition, to rejuvenate sperm production, and avoid IVF when it’s not warranted.
Sperm motility measures the percentage of sperm that are able to swim. For natural conception to take place, sperm need to travel the relative distance of a human swimming from California to Australia, so motility very much matters. Doctors generally consider the signal to be normal if more than 32 - 40% of sperm in a given sample are swimming. When looking at the group of 1,800 men who conceived naturally, very few (<2.5%) succeeded with measures below 30%.
Sperm morphology measures the percentage of sperm that are normally shaped. While shape matters for myriad reasons, namely the shape must be appropriate to penetrate the egg, it is often the most subjective of the major semen analysis parameters.
Doctors consider morphology to be OK when more than 12% of sperm in a given sample are normally-shaped, and indeterminate when 9 – 12% are normally-shaped. However, when we look at the sample of 1,800 men who conceived naturally, men with morphology rates as low as 3 – 5% were successful. There is real debate in the field about what to do with men who have an otherwise strong sperm concentration and motility, but a low percentage of normally-shaped sperm.
Many reproductive endocrinologists believe this is grounds to proceed to IVF using ICSI, while many urologists still think this patient could conceive naturally, through IUI, or through IVF without ICSI. The study below shows there is room for discussion on whether ICSI is necessary for patients who only have diminished morphology.
In addition to the three main factors discussed above, there are a handful of other parameters the laboratory will pay attention to, namely the pH levels of the sample (7.2 – 7.8 is normal), the speed at which the specimen changes into a watery consistency (15 – 30 minutes is normal) and whether the sample’s appearance is white/grey (red or brown could indicate there is blood or jaundice).