The term sperm refers to the microscopic cell formed by a head and a tail, and it is a small part of the seminal fluid, also known as semen. The sperm fertilizes the egg inside the woman's body, while the semen transports the sperm into the female reproductive tract (1).
One of the main surveys performed to assess male infertility is the semen analysis. In this study, the physical characteristics of the semen are analysed (volume, pH, colour, liquefaction, and viscosity) as well as the sperm motility, vitality, concentration, and morphology (2). The World Health Organization (WHO) has created a manual with the reference values for all these parameters. Two main attributes are measured in the semen: the total number of spermatozoa, which reflects the sperm production; and the total fluid volume made by the accessory glands (3).
According to the WHO, healthy semen contains between 15 to 250 million sperm per milliliter, of which at least 40% have good motility, and during ejaculation 2 to 5 milliliters of semen are produced (4).
Inside the vagina, sperm can live up to 5 days after intercourse in a favourable environment, such as a fertile cervical mucus, a sign that ovulation is approaching. Nevertheless, due to factors like the acidness of the vagina, only a few sperms will survive the first 12 hours and reach the fallopian tubes (5).
Added to this, studies have shown that in Western countries such as Australia, New Zealand, North America, and European countries, the sperm concentration decreased 52.4 % and the sperm count 59.3 % between 1973 and 2011. Some of the reasons for this decrease have been attributed to the modern environment, including endocrine-disrupting chemicals, pesticides, heat, diet, stress, smoking, and the body mass index (BMI) (6).
To maintain good sperm health, it is recommended to wear loose cotton boxers and to lose weight in the case of obesity or overweight through a healthy diet and exercise. Also, it is important to avoid heavy alcohol consumption, smoking, and drugs intake. A blood test is advisable to identify vitamin deficiencies, and if that is the case then it is recommended to take vitamin supplements (7).
In men without fertility problems, it is suggested that a sexual abstinence period of about 2 to 3 days but no more than 7 days should be given to replenish the ejaculated sperms and allow the body to reproduce more sperms of higher quality. This is because having sex very frequently increases the risk of depleting their sperm stores. However, longer periods of abstinence (more than 7 days) could lead to lower sperm qualities (8).
- Male contraceptive initiative. 2021. Semen vs sperm. Accessed 3 October 2021 , https://www.malecontraceptive.org/blog/semen-vs-sperm
- Patel AS, Leong JY, Ramasamy R. Prediction of male infertility by the World Health Organization laboratory manual for assessment of semen analysis: A systematic review. Arab J Urol. 2017;16(1):96-102. doi:10.1016/j.aju.2017.10.005
- World Health Organization. 2010. Laboratory manual for the Examination and processing of human semen. 5th edition. Accessed 3 October 2021 https://www.who.int/docs/default-source/reproductive-health/srhr-documents/infertility/examination-and-processing-of-human-semen-5ed-eng.pdf
- Mayo clinic. Healthy sperm: Improving your fertility. https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/fertility/art-20047584
- Clubb E. Natural methods of family planning. J R Soc Health 1986, 106(4):121-6. doi: 10.1177/146642408610600402.
- Levine H, Jørgensen N, Martino-Andrade A, Mendiola J, Weksler-Derri D, Mindlis I, Pinotti R, Swan SH. Temporal trends in sperm count: a systematic review and meta-regression analysis. Hum Reprod Update. 2017 Nov 1;23(6):646-659. doi: 10.1093/humupd/dmx022.
- Chertoff J. & Murrel D. 2018. Healthline. What Is a Normal Sperm Count? Accessed 4 October 2021, https://www.healthline.com/health/mens-health/normal-sperm-count
- AlAwlaqi A & Hammadeh M. Sexual Abstinence and Sperm Quality. International Journal of Women’s Health and Reproduction Sciences 2017, 5(1): 11-17.