Main causes of male infertility
Professor João Luís Silva Carvalho, Clinical Director of CETI and professor at the Faculty of Medicine of Porto (FMUP), was the author and coordinator of the AFRODITE study, the first epidemiological study on infertility in Portugal, which concluded that 9% of couples are infertile in Portugal.
The study reveals that 260 to 290 thousand couples are unable to have children, and the problem does not only affect women.
According to data from the Portuguese Fertility Association (APF), although infertility is often associated with women, the truth is that the percentage of cases of female and male infertility is exactly the same, 40%.
What is the main cause of infertility in men?
There are several causes of male infertility, however, and according to the Portuguese Society of Reproductive Medicine (SPMR), semen abnormalities are the main cause of male infertility. There are also other causes of infertility, such as varicocele, infections in the reproductive system, hormonal problems or genetic problems.
The main problems related to semen abnormalities are:
- Decreased sperm count
Under normal conditions, a man produces more than 100 million sperm in each ejaculation. However, although only one sperm is needed to fertilize an egg, the truth is that the overwhelming majority of sperm are lost or die en route. Therefore, if a man produces less than 20 million sperm in his ejaculate, his fertility is significantly reduced and the likelihood of pregnancy occurring is much lower.
- Sperm with reduced mobility
Low motility is often associated with decreased sperm concentration. In normal sperm, at least 50% of the sperm should move adequately. Below this limit, the man is said to have asthenospermia or asthenozoospermia. Reduced motility is in itself more significant than a moderate reduction in sperm count.
- Sperm with abnormal configuration
A sperm that has more than 15% of morphologically normal sperm is considered normal. If this percentage is less than 15%, teratospermia or teratozoospermia is said to exist. Abnormal sperm are not fertilizing, which is an important cause of infertility.
- Absence of sperm
In some men, the ejaculate does not contain sperm. This condition is called azoospermia and means that the testicles do not produce sperm or that the tubes that carry sperm out of the testicles are blocked.
How is male infertility diagnosed?
Diagnosis begins with a medical consultation, where the man’s entire clinical history is assessed, taking into account factors such as smoking, drug use or alcoholism, for example, and a complete physical examination is also carried out.
The main test for assessing male infertility is a sperm count, through which the doctor assesses the quantity and quality of sperm produced. This test should be repeated if the values are altered. Certain situations also require a hormonal or genetic study. In cases where there are no sperm in the semen, it may be necessary to perform a testicular biopsy to check whether sperm are being produced.
What are the main risk factors that can cause infertility in men?
- Stress: o excesso de ansiedade, muitas vezes, pode resultar na falta de libido sexual e na perda de ereção. O stress origina também uma redução da quantidade de esperma.
- Tabagismo: o tabaco reduz a motilidade dos espermatozoides e o volume das ejaculações.
- Alcoolismo: o consumo excessivo de bebidas alcoólicas, origina desequilíbrios hormonais, diminui os níveis de testosterona, o que pode prejudicar a produção de esperma e está associado a um declínio significativo na qualidade do esperma.
- Consumo de drogas: o consumo de cannabis, cocaína e a heroína, por exemplo, afeta a morfologia e quantidade de espermatozoides, visto serem bastante nocivas para a fertilidade.
- Obesidade: o excesso de peso facilita o desenvolvimento de doenças crónicas, como a diabetes, que originam uma baixa qualidade e quantidade de espermatozoides, e também afeta os níveis hormonais (testosterona).
- Sedentarismo: a falta de exercício físico regular provoca efeitos adversos na saúde masculina. Uma vida sedentária afeta a qualidade e a concentração dos espermatozoides.
- Exposição a substâncias tóxicas: a exposição ocupacional a solventes orgânicos e a substâncias químicas tóxicas, comprometem a qualidade dos espermatozoides.
- Excesso de calor: a exposição excessiva ao calor tem um impacto negativo no DNA dos espermatozoides. Os testículos têm de ser mantidos entre três e quatro graus abaixo da temperatura corporal, pois o calor afeta a qualidade do sémen.
How is male infertility treated?
Treatment for infertility in men is normally carried out according to the cause of the problem, and can be done using medication, artificial insemination, surgery, assisted reproduction or a combination of several techniques.
Currently, there is a wide range of treatments available and advances in science make it possible to treat most cases of infertility. Treatment may involve correcting the causes or, when this is not possible, using medically assisted reproduction techniques, which can resolve cases that were difficult to resolve a few years ago.