My name is Dr. Lowell T. Ku, M.D. and I am an infertility specialist in Dallas, Texas. I am one of the physicians in Dallas IVF. It is my honor and pleasure to provide my thoughts for Terminology Tuesdays.
Recently, a question was posed concerning low sperm count.
The World Health Organization (WHO) suggests that a normal sperm count be at least 20 million sperm/mL in a single semen specimen.1
Although a sperm count of at least 20 million sperm/mL is the generally accepted standard among many IVF centers in America, some centers may have a different lower limit of normal for an acceptable sperm count. We at Dallas IVF use 20 million/mL as our lower limit of normal.
Thus, a low sperm count (also known as oligospermia) occurs when there is a concentration of less than 20 million sperm per mL. Severe oligospermia occurs when the sperm concentration is below 5 million/mL. However, there is variability in sperm counts that can be seen in successive semen specimens from the same individual. Thus, at least 2 samples obtained at least 4 weeks apart should be screened before an individual should be considered as having a low sperm count.
A study published in the Lancet in 1998 found that the probability of conception increased with increasing sperm concentrations up to approximately 40-50 million/mL. However, the chance of conception does not increase anymore with higher sperm densities.2
The number of sperm (concentration) is not the only sperm parameter that infertility doctors evaluate when evaluating whether a man is fertile, subfertile, or infertile. Other major sperm parameters include the motility (movement) and morphology (shape) of the sperm.
When evaluating for the motility of the sperm, we look for the percentage of the total sperm population exhibiting any motion. Sperm can be further graded for the percentage with purposeful forward motion.
Using the most current and rigorous standards, the majority of sperm can be found to have physical abnormalities such as an abnormally shaped sperm head (too big, too small, or too many), neck (midpiece), or more than one tail. When looking at the morphology of sperm, we look at the percentage of normal appearing sperm. The sperm must have one normal shaped head with one normal neck and one tail.
A landmark study published in the New England Journal of Medicine in 2001 revealed that the odds of male infertility increase with the number of major semen parameters (concentration, motility, morphology) in the subfertile range. The probability of male infertility is 2-3 times higher when 1 parameter is abnormal, 5-7 times higher when two are abnormal, and 16 times greater when all three are abnormal.3
The prognostic value of a routine semen analysis can be increased when combining the sperm count with the percentage of motile sperm to give a total motile sperm count (total sperm in ejaculate x percent motility). The total motile sperm count allows for the determination of the total number of active sperm. A study published in the British Journal of Urology in 1986 found that men with a total motile sperm count of greater than 10 million have a higher pregnancy rate than those with 2-10 million total motile sperm.4
We will discuss some of the possible options to help you conceive when your husband has a low sperm count in next week’s installment of Terminology Tuesdays.
1. World Health Organization, Laboratory Manual for the Examination of Human Semen and Sperm-Cervical Mucus Interaction, 5th, Cambridge University Press, 1999.
2. Bonde JP, Ernst E, Jensen TK, Hjollund NH, Kolstad H, Henriksen TB, Scheike T, Giwercman A, Olsen J, Skakkebaek NE, Relation between semen quality and fertility: a population-based study of 430 first-pregnancy planners, Lancet 352:1172, 1998.
3. Gucik DS, Overstreet JW, Factor-Litvak P, Brasil CK, Nakajima ST, Coutifaris C, Carson SA, Cisneros P, Steinkampf MP, Hill JA, Xu D, Vogel DL, Sperm morphology, motility, and concentration in fertile and infertile men, New Engl J Med 345:1388, 2001
4. Hargreave TB, Elson RA, Fecundability, rates from an infertile population, Cr J Urol 58:194, 1986.
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