Male subfertility: One sperm does the job, many is company

Subfertility is as ancient as humanity and it takes a couple time to realise they may not easily achieve a pregnancy, except in very few obvious situations.

A couple not using any form of birth control may notice after a few months that they have not been able to conceive. Most of the time, if this is less than a year, it may still happen without the need for worry.

In about one in six couples, however, there would usually be a need for further evaluation.

The causes of delayed conception could be related to the female or male partner. Today, we shall expound on male-related causes of subfertility.

Sperm production in the testes is a continuous process that happens in waves of three monthly cycles from initial stages of development to maturity and the ability to fertilise the female egg. Due to chance, natural attrition, and need to navigate a complex female reproductive tract, millions of sperm are required to enhance the probability to fertilise the egg at ovulation.

Various factors may affect the production and delivery of competent sperm and ability to maintain normal fertility. Decreased formation of sperm or a blockage of special ducts in the genital system leads to very low or no sperm count in the ejaculate. It requires that a semen sample is analysed in the laboratory. A strong sperm needs to be normal in appearance and agile.

The formation of sperm is a delicate process controlled by lifestyle and genetic factors. Medical treatments and recreational activities may also affect this process, albeit temporarily in most instances. The scrotum is a loosely hanging skin from the rest of the body to maintain a low temperature for sperm maturation to thrive. The testes also produce the hormone testosterone that is key for male vitality. Disruption in sperm production may also affect testosterone levels. Ironically, however, replacing testosterone leads to a further decline in sperm formation.

There is a global increase in lifestyle conditions such as obesity, smoking, hypertension, and diabetes with a corresponding decline in sperm parameters. Though mechanisms involved may be complex, a reversal of obesity and cessation of smoking improves fertility. It is notable that with increasing weight, testosterone levels decline.

In certain circumstances, there may be a genetic alteration in the chromosome constitution leading to abnormal sperm production or delivery. We all inherit each half of our chromosomes from the female and male parents respectively. Rarely, this process may go wrong and extra genetic material comes into our cells or there is a rearrangement of the normal order. Whereas this may not lead to any physical ill-health, the genetic engine driving sperm formation is chocked resulting is in very minimal to no sperm production. Knowing whether a genetic cause exists requires specialised testing, known as karyotyping. Some of the conditions that may come upon this test including Klinefelter syndrome. Genetic abnormalities in sperm may also be a cause for recurrent pregnancy loss.

Genital infection by sexually transmitted infections such as gonorrhoea or chlamydia may cause damage to sperm delivery. This is comparable to when the ducts are blocked in the surgical procedure of vasectomy. It is very unlikely that self-examination may reveal an underlying problem unless there is obvious swelling in the scrotum or one testicle is clearly diminished in size. A medical assessment is therefore advised. Whereas this does not alter sexual function, the absence of sperm is only noticeable during a sperm test.

Achieving pregnancy requires that a couple have regular unprotected intercourse two to three times a week. This keeps pace with the regeneration of new viable sperm and may improve health and wellness. Where sperm count is decreased, but not critically low, simple lifestyle advice may suffice to enhance a chance of conception. This likelihood is highest within the first two years of trying, therefore prolonged waiting could be counterproductive, and especially where the female partner is older than 35 years as fertility would decline thereafter. If simple measures have not been successful, advice from a fertility specialist should be sought. The place of intrauterine insemination is limited particularly where couples are able to achieve regular intercourse.

Although many sperm is a company and not a crowd for male fertility, certain treatments only need one sperm cell. This requires a specialised technique known as intracytoplasmic sperm injection (ICSI), where a single sperm cell is injected directly into the egg. This treatment requires the female partner to undergo hormone stimulation of her ovaries to produce multiple eggs, commonly known as in vitro fertilisation (IVF). We also apply this technique for couples where there is no sperm on the ejaculate, though retrievable directly from the testes. Reassuring, babies born using these techniques are in sound health as those conceived naturally.

Dr Muteshi is a Consultant in Reproductive Medicine and Fertility at Aga Khan University Hospital, Nairobi