Causes of infertility among men
There can be multiple reasons for male factor infertility, the important ones being:
Abnormal semen parameters - example, azoospermia (nil sperm count), oligospermia (low sperm count), asthenospermia (poor motility of sperms) and teratospermia (abnormal shape of sperms)
Physical problems - example, cryptorchidism (undescended testes), varicocele, premature ejaculation, absence of ejaculation (anejaculation) and erectile dysfunction
Psychological and/or behavioural problems - example, erectile dysfunction and ejaculatory dysfunction
Azoospermia is a major correctable cause of of male infertility. It is important to understand the structure and functioning of male reproductive system in some detail to understand it's treatment.
Structure of male reproductive system
The male reproductive system consists of following organs -
A pair of testes
Secretory ducts - epididymis, vas deferens and ejeculatory ducts
Accessory structures - prostrate, seminal vesicles and bulbourethral glands
Testes are responsible for release of male sex hormone called testosterone and for production of sperms. Penis contains urethra, which releases urine as well sperms from the body. A stiff penis is essential for copulation and to provide passage for sperms inside the vagina for reproductive process to take place.
How does the male reproductive system work
The two essential contributors to male fertility are sperm production and sperm transport, which go hand in hand in a long and continuous process taking up to 3 months.
The testes of an adult man produce millions of sperms everyday under influence of the hormone testosterone.
The process of sperm production or spermatogenesis starts in the seminiferous tubules of the testis, where sperm cells undergo repeated cell division to finally produce a mature sperm.
The sperms are then stored in the epididymis till they are fully mature and have gained the ability to swim.
The next passage of the sperms is in the vas deferens - tubes connecting the epididymes to urethra via the ejaculatory duct. It is from the urethra that the sperms are ejaculated during coitus.
The seminal fluid plays a vital role in mobility of sperms and their ability to fertilize the egg. It consists of secretions from seminal glands, prostrate and Cowpers gland.
In addition to healthy structures mentioned above, adequate levels of male hormone (testosterone) and ambient temperature of the scrotum are also essential for sperm production and maturation.
Evaluation of male partner
Evaluation of the male partner includes detailed history, thorough physical examination and semen analysis. In some cases, assessment of semen sample using advanced techniques can provide additional insights into the causation of male infertility.
Laboratory assessment of semen for the quality and quantity of sperms is the cornerstone of assessment of male partner. Semen analysis is mostly the first investigation recommended for the male partner.
Guidelines for semen analysis
The semen sample sample should be collected in a sterile container by masturbation after an abstinence of 3-5 days.
The sample is left to liquefy for about 30 min as semen is a viscous liquid.
Liquified semen is placed on a slide for microscopic assessment of count, motility and morphology of the sperms in the sample.
At least 2 semen analyses performed at least 6 weeks apart are essential for proper evaluation and arriving at a diagnosis.
Normal semen parameters
Sperm concentration – often referred to as a sperm count, it is the number of sperms present in each ml of fluid. Sperm count of over 15 million/ ml is treated as normal count.
Sperm motility – it is the percentage of sperms which are mobile. At least 40% of the sperms in an ejaculate should be motile and 32 % sperms should be progressively motile, for the sample to be taken as normal.
Semen volume – it refers to the total amount of fluid collected in the sperm sample. Semen volume between 1.5 - 5 ml/ ejaculate is considered normal.
Total motile sperm count – it refers to count of total number of moving sperm in the sample. Normally, there are at least 15 million motile sperms in a sample.
Sperm morphology – it refers to the shape of the sperms. Surprisingly, abnormally shaped sperm are quite a common occurrence. As per the latest WHO criteria for assessing morphology of sperms, a sample is considered normal if it carries more than 4% normal shaped sperms.
Viscosity – it refers to thickness of the sperm fluid. Low or moderate viscosity is considered normal.
Leukocytes – leucocytes are the white blood cells, significant presence of which in the semen is a sign of inflammation or infection. Presence of more than one million leukocytes/ ml of semen is considered abnormal.
Advanced techniques of sperm assessment
Advanced techniques of sperm assessment are used in specific cases and these can help in pinpointing specific issues with the sperms. Some of the more frequently used advanced techniques include -
Vitality Testing – vitality testing is helpful if all the sperms in the semen sample are immotile. This test helps in differentiating dead immotile sperms from viable immotile sperms. The viable immotile sperms can be picked and used for fertilising the eggs with IVF/ICSI.
DNA fragmentation Index (DFI) – DFI is a test to detect the percentage of sperms DNA fragmentation in a semen sample. Sperm DNA fragmentation refers to the breakage in the DNA of the sperm and indicates the damage to the genetic material of the sperm, which causes infertility. Presence of increased DNA fragmentation has been found to correlate with ICSI failures, recurrent miscarriage and poor pregnancy outcomes.