Low Sperm Counts – Some General Considerations
It is not uncommon in the course of an infertility evaluation to find that the sperm count is “low”. Usually, a finding such as this leads to a careful evaluation of the male partner including a physical examination by a urologist and will usually include an ultrasound evaluation of the testes as well as endocrine and sometimes genetic evaluation. To discuss therapeutic options in a meaningful way it is important to quantify what is meant by the term “low” when describing an abnormal sperm count. Usually this term refers to the actual sperm count and describes the number of sperm found in each one milliliter of semen. It is derived through microscopic evaluation of the number of sperm seen on a specially designed glass slide. The slide contains a grid and sperm cells are counted within each of the squares on the grid. Based on the known size of each of the squares on the grid, the thickness of the layer of semen, and the known microscopic magnification being used, a mathematical calculation is used to determine the sperm count.
Semen Parameters
A normal semen specimen contains 20-100 million sperm/ml of which greater than 50% of the sperm should demonstrate movement (motility). Another important parameter evaluated at the time of a complete semen analysis is morphology. This refers to the microscopic size and shape of individual sperm cells. It is generally felt that sperm that have a “normal” appearance are more likely to fertilize. In terms of morphology, several different criteria may be used to determine whether a sperm cell is normal, but today the majority of reproductive specialists use “strict criteria”. This means that the laboratory technician will be very strict in determining whether an individual sperm cell is normal. Using these criteria, when 4% or more of the cells examined are microscopically normal, the specimen is described as having normal morphology.
It is helpful to make some distinction between various degrees of abnormality when considering therapeutic approaches to low sperm counts. For simplicity, considering only the actual sperm count, it would be reasonable to categorize a sperm count below 5 million/ml as extremely low, while a count of 5-10 million/ml is very low, and a count of 10-20 million/ml moderately low. These descriptions do not take into account the percentage of motile sperm or the percentage of morphologically normal sperm, and therefore they do not fully describe the fertility potential of a given semen sample. This description does however provide a simple framework for discussing therapeutic approaches.
Sperm counts in the extremely low range require comprehensive evaluation by a male infertility specialist because the sperm count may be an indication of underlying medical or genetic problems. If correctable problems are present such as hormonal deficiencies or anatomical problems such as dilated scrotal veins (varicocoels), these conditions may be corrected in an attempt to improve sperm production. When the sperm count remains in the extremely low range, in-vitro fertilization (IVF) with direct injection of a single sperm cell into each mature egg (ICSI) is the best approach, and is highly effective. When sperm counts are in the 5-10 million/ml range, simpler treatment such as intra-uterine insemination (IUI) may be effective and can be offered. Studies have suggested that IUI may succeed if 5 million motile sperm can be extracted from the semen sample. To determine if 5 million sperm can be extracted from the sample, the laboratory must perform a routine sperm wash procedure that involves a filtration process with centrifugation of the specimen. If the sperm wash procedure results in isolation of 5 million motile sperm, 3 cycles of intra-uterine insemination should be tried before consideration of IVF/ICSI.
When the sperm count is moderately low (10-20 million/cc), 3 cycles of intra-uterine insemination should be attempted before considering IVF/ICSI.
It is important to recognized that we have presented a somewhat over simplified discussion of this topic. Clearly, real world clinical situations involve a careful consideration of all aspects of the semen analysis including volume, count, motility, morphology, and quality of motion. Approaches to treatment should take all semen parameters into consideration.
Once a low sperm count has been identified, it is important to carefully review the male partner’s history and recommend lifestyle modifications if indicated (i.e. decrease alcohol consumption, stop smoking, discontinue recreational drug use, etc.). In addition, nutritional supplements which may include coenzyme Q10, B12, selenium, vitamin C, folic acid, L-carnitine, fumarate, and acetyl L-carnitine should be recommended in an attempt to improve sperm production while the couple is completing their infertility evaluation and preparing for treatment. Production of sperm cells originates in the testicles and requires 80-90 days to complete. Therefore, implementation of any treatment to improve sperm production requires 80-90 days before results may be assessed.
