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What Is the Role of Sperm Motility in Fertility

Role of Sperm Motility in Fertility | Causes of Low Sperm Motility

Sperm health is an essential contributing factor in a couple’s ability to conceive. Being unable to conceive after two years of trying is labeled as infertility. Around 15 to 20 percent of the world population is affected by infertility, and among them, 30 to 40% falls under the male infertility factors, including sperm motility. The common male infertility factors are:

  • Low sperm count is referred to as oligospermia.
  • Abnormal sperm shape referred to as teratozoospermia.
  • Low sperm motility referred to as asthenozoospermia/asthenospermia.

What is Sperm Motility?

Sperm motility is defined as the ability of sperm to move or swim through the female genital tract to reach and fertilize the egg. Sperm motility is of two types:

  • Progressive Motility: this type refers to the sperms moving in a straight line or large circles.
  • Non-progressive Motility: this type refers to the sperms that do not move in a straight line or swim in small circles.

For sperm to move through cervical mucus to the egg for fertilization, it must have progressive motility of at least 25 micrometers per second. Asthenozoospermia (poor sperm motility) is diagnosed when less than 32 percent of sperms have progressive Motility.

Causes of Low Sperm Motility

The cause of low sperm motility can vary among individuals. It can go unexplained in some cases, while some may have a genetic cause, lifestyle, or environmental factors. Usually, it is believed that anything that puts stress or damages testicles has a negative impact on sperm motility. Common causes are:

  • Infection, Injury
  • Testicular cancer.
  • Testicular surgery.
  • Undescended testis.
  • Varicocele
  • Smoking and long term use of anabolic steroids also affect sperm count and Motility.

Role of Sperm Motility in Fertility

As already mentioned, that sperm has to be motile enough to travel through the female reproductive tract for fertilization. If sperms are not motile, they cannot reach the egg, and that ultimately leads to infertility. Among the causes of infertility worldwide, 40 to 50 percent of cases are due to male factor infertility, and sperm motility is one of the causes of male factor infertility.

Semen analysis is a diagnostic test used to detect a fertility problem. It is specific, and 9 out of 10 infertile men can be diagnosed only by a semen analysis.

Semen analysis is a diagnostic test used to detect a fertility problem. It is specific, and 9 out of 10 infertile men can be diagnosed only by a semen analysis. The man giving sample is asked to abstain from sexual activity for 2 to 7 days to increase the semen volume. Usually, two samples are taken anywhere between 2 to 4 weeks apart because the sample quality can be affected by illness and the amount of time passed since sexual activity. The sample is then evaluated for sperm count, movement, and interaction with seminal fluid. If the percentage of progressively motile sperms comes out less than 32 percent, poor sperm motility is diagnosed.

How to Improve Sperm Motility?

Lifestyle changes can affect sperm motility and can help to improve the Motility and quality of sperms. Exercising regularly, quitting alcohol and smoking, exercising regularly, and maintaining a healthy weight are some measure which can help to improve sperm motility. Some supplements are also known to have a positive effect on sperm motility. These include selenium and Vitamin E supplementation. A study showed men who took 200 micrograms of selenium and 400 micrograms of Vitamin E showed a 52 percent increase in sperm motility. But it is recommended to consult a doctor before taking these supplements. If sperm motility is affected by hormonal problems, then taking follicle-stimulating hormone or human chorionic gonadotropin medication depending on the hormonal imbalance may help. Apart from all these, if sperms are healthy, then pregnancy with low sperm motility can occur using in vitro fertilization or intrauterine insemination.


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