What is male sterility?
Male sterility corresponds to a reduced reproductive capacity in men and contributes for 50% to sterility in couples. The condition of male sterility is determined when certain conditions occur, like for example azoospermia, that is the total absence of spermatozoids, criptozoospermia, which indicates the drastic lack of spermatozoids in seminal fluid, or in case of absence of ejaculation (anejaculation) or necrozoospermia that occurs when the spermatozoids present in seminal fluid are dead. Sterility is defined as primary when a man has never been able to induce a pregnancy, and secondary when he has been previously able to induce a pregnancy. There are different causes of sterility: genetic, anatomical, infectious and hormonal.
What are the possible hormonal causes of male sterility?
In men, LH and FSH gonadotrophins are involved in the production of testosterone and in spermatogenesis, that is the process that leads to the maturation of spermatozoids. Altered values of such hormones may cause sterility in men. A high FSH value may indicate primary testicular insufficiency, also known as primary hypogonadism, that is the incapacity of the male gonad to perform spermatogenesis and/or to produce male sex hormones. Given the scarce production of such hormones, the hypophysis is induced to produce excessive FSH in order to stimulate and encourage the testicle. On the contrary, low FSH levels are often associated to azoospermia and are the cause of secondary hypogonadism. In many cases, prolactinoma is also a cause of sterility as it is a benign tumour of the pituitary gland that leads to hyperprolactinemia. In men, high prolactin levels in the blood cause a great reduction of libido and impotence and are often associated to alterations of the quality of seminal fluid and therefore to sterility.