Semen quality

From Wikipedia, the free encyclopedia

Semen quality is a measure of the ability of semen to accomplish fertilisation. Thus, it is a measure of fertility in a man. It is the sperm in the semen that are of importance, and therefore semen quality involves both sperm quantity and sperm quality.

Contents

[edit] Tests

[edit] Semen analysis

Main article: Semen analysis

A semen analysis typically measures the number of sperm per milliliter of ejaculate, and analyzes the morphology (shape) and motility (ability to swim forward) of the sperm. Also usually measured are the concentration of white blood cells, the level of fructose in the semen, and the volume, pH, and liquefaction time of the ejaculate.[1][2]

A number of factors may influence the accuracy of semen analysis results, and results for a single man may have a large amount of natural variation over time.[3] For this reason, a subfertile result must be confirmed with at least two further analysis.[4]

[edit] Hamster zona-free ovum test

Main article: Hamster zona-free ovum test

A man's sperm are mixed with hamster eggs that have had the zona pellucida (outer membranes) removed, and the number of sperm penetrations per egg is measured. The human sperm does not fertilize the hamster eggs.[5] A negative result on the hamster test correlates with a lower probability of the man's partner becoming pregnant.[6]

[edit] Sperm chromatin assay

Chromatin is the complex of DNA and protein that make up chromosomes. If a large percentage of a man's sperm (greater than 30%) have damaged chromatin, his chances of impregnating a partner are significantly reduced, and if he does impregnate his partner, she faces an increased risk of miscarriage. The portion of a man's sperm with damaged chromatin may be determined with a Sperm Chromatin Structure Assay (SCSA).[7]

[edit] Cryopreservation

When performing cryopreservation of semen, it is the sperm quality after reviving the sample that is of importance, because many sperm cells die in the process.

To be of use in assisted reproductive technology, the sample should after thawing have more than 5 million motile sperm cells per ml with a good grade of motility. If the grade of motility is poor, 10 million motile cells per ml is required.[8]

[edit] Bad freezers

In 10-20% of all men, the semen doesn't endure cryopreservation.[8] The cause is unknown.

[edit] Factors

There are many factors that influence the sperm quality. If exposure to any of them has happened, it might take up to 3 months before the sperm quality is up to normal again, because that's how long time spermiogenesis takes.[8]

[edit] Heat

Semen is heat-sensitive, and cannot endure too high temperatures. The body has compensatory mechanisms, like the cremaster muscle relaxing and letting the testicle further away from the warm body, sweating and a Countercurrent exchange of blood cooling inflowing blood. However, despite the compensation of the body, there are activities that should not be performed too often, in order of preventing infertility due to heat;

Fever also raises the body temperature, which can strike sperm quality.

In the same way, sperm quality can be lower in the summer.[8]

[edit] Physical trauma

A blow from outside doesn't affect the sperm quality of already produced sperm cells. Furthermore, the testes are well protected in the scrotum, for example by the tunica vaginalis, making the testes slide away from external pressure rather than being malformed from it. However a hard enough hit can close or crush the capilliaries that produce sperm, resulting in permanent or temporary partial or total inability to produce sperm in the affected testicle.

[edit] Chemicals

There is suspicion that many toxic substances in the environment influence sperm quality[8]. While a few chemicals with known effects on fertility have been excluded from human consumption, we cannot know if others remain undiscovered. Gossypol present in crude cottonseed oil (and potentially the organ meats from animals poisoned with it[9]) has been associated with reduced sperm production. Misuse of anabolic steroids can cause testicular atrophy and reduced fertility. Depo-Provera, Adjudin, and gossypol are examples of substances used as male contraceptives or in chemical castration. Recent studies have found that THC present in marijuana can confuse the movements of intact sperm, reducing their ability to achieve fertilization.[10][11]

[edit] Hormones

Changes in hormone homeostasis affects the spermatogenesis. Therefore, abuse of e.g.anabolic steroid can reduce sperm quality.

The body also has natural variations in hormone concentrations, giving sperm quality natural fluctuations as well.[8]

[edit] Last ejaculation

How long the man has abstained prior to providing a semen sample correlates with the results of semen analysis and also with success rates in assisted reproductive technology (ART).

Both a too short period of time since last ejaculation and a too long one reduces semen quality.

  • A period of time of less than one day reduces sperm count by at least 20%. [12]
  • Longer periods of abstinence correlate with poorer results - one study found that men with repeated normal results from semen analysis produced abnormal samples if they abstained for more than 10 days. Another study found that couples where the man had abstained for more than 10 days before an intrauterine insemination (IUI) had only a 3% pregnancy rate.[13]

[edit] Environment

For semen that has been ejaculated, the quality deteriorates with time. However, this lifetime can be shortened or prolonged, depending on the environment.

[edit] Outside body

Sperm outside of the body generally has a life expectancy which is considered to depend on pH, temperature, presence of air and other factors, and is unpredictable but smaller than the life expectancy inside the human body.[citation needed] For instance, sperm donors who collect the sample outside the clinic are advised to have handed in the sample before one hour from collection, and to keep them in, if not at body temperature, then at least at room temperature.[14]

[edit] In female

The environment in the uterus and fallopian tubes are advantageous. A pregnancy resulting from sperm life of eight days has been documented.[15][16][17]

[edit] Home or in clinic

The sperm quality is better if the sample is collected at home than in the booths in the clinics [18]. Collecting the sperm at home gives a higher sperm concentration, sperm count and motility.[18]

[edit] Others

Coffee, alcohol and smoking lowers the sperm quality. However, the influence is probably minor.[8] Long-term stress is also suggested.[8]

Malnutrition or an unhealthy diet can lead to e.g. Zinc deficiency, lowering sperm quality.

Sperm quality is better in the afternoon than in the morning.[19]

Lack of exercise, as well as excessive exercise, are minor factors.

[edit] References

  1. ^ Understanding Semen Analysis. Stonybrook, State University of New York (1999). Retrieved on 2007-08-05.
  2. ^ Essig, Maria G.; Edited by Susan Van Houten and Tracy Landauer, Reviewed by Martin Gabica and Avery L. Seifert (2007-02-20). Semen Analysis. Healthwise. WebMD. Retrieved on 2007-08-05.
  3. ^ Adequate Analysis Frequency. Kokopelli Technologies (2007). Retrieved on 2007-08-11.
  4. ^ Weschler, Toni (2002). Taking Charge of Your Fertility, Revised Edition, New York: HarperCollins, p.189. ISBN 0-06-093764-5. 
  5. ^ C. Matthew Peterson, Kirtly Parker Jones, Harry H. Hatasaka, and Kenneth H. H. Wong (October 2002). "Hamster Egg Penetration Test" (PDF). . Utah Center for Reproductive Medicine Retrieved on 2007-08-08.
  6. ^ Koulischer L, Debry JM (1989). "The hamster test. Practical consequences" (in French). Acta urologica Belgica 57 (1): 77–81. PMID 2718849. 
  7. ^ Ellington, Joanna (2004). Sperm Chromatin Assay. INGfertility. Retrieved on 2007-08-11.
  8. ^ a b c d e f g h i j k l Cryos(Danish)
  9. ^ Merck Veterinary Manual.
  10. ^ WebMD: Smoking marijuana lowers fertility.
  11. ^ PMID 16500334
  12. ^ Nnatu SN, Giwa-Osagie OF, Essien EE (1991). "Effect of repeated semen ejaculation on sperm quality". Clin Exp Obstet Gynecol 18 (1): 39–42. PMID 2054949. 
  13. ^ Ellington, Joanna (2004). How Long to Abstain for a Sperm Test/Analysis. INGfertility. Retrieved on 2008-06-07.
  14. ^ Sahlgrenska University Hospital (SU) - reproduction medicine
  15. ^ Ball M (1976). "A prospective field trial of the "ovulation method" of avoiding conception". Eur J Obstet Gynecol Reprod Biol 6 (2): 63–6. doi:10.1016/0028-2243(76)90004-6. PMID 985763. 
  16. ^ Dr Evelyn Billings & Ann Westmore (2005). Trials of The Billings Ovulation Method. Retrieved on 2005-11-03.
  17. ^ Sinha G, Sinha A (1993). "A field trial of Billings' ovulation method for spacing and limitation of birth". J Indian Med Assoc 91 (10): 255–6. PMID 8308307. 
  18. ^ a b Elzanaty S, Malm J (2007). "Comparison of semen parameters in samples collected by masturbation at a clinic and at home". Fertil Steril. doi:10.1016/j.fertnstert.2007.05.044. PMID 17658521. 
  19. ^ Cagnacci A, Maxia N, Volpe A (1999). "Diurnal variation of semen quality in human males". Hum. Reprod. 14 (1): 106–9. PMID 10374104. 
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