Fertility, the ability to conceive a child, is a complex process influenced by a multitude of factors. Although often seen as a primarily female concern, male fertility plays an equally crucial role in conception. Infertility, which affects a growing number of couples worldwide, can be the result of a variety of causes, ranging from genetic factors to environmental and lifestyle influences. In this context, it is essential to understand how and why these elements affect fertility, not only to help couples overcome the challenges of conception but also to better understand reproductive health in general.
A recent study was published on October 12, 2023, in the journal Nature Reviews Urology. It was carried out by an international group of 26 scientists, led by Moira O’Bryan from the University of Melbourne. Sarah Kimmins, a professor at the University of Montreal and researcher at the CHUM Research Center, was the first author of this study. The results of this research has been highlighted in various articles, notably on the INRS and University of Montreal websites, indicating that one couple in six is affected by infertility, and in half of the cases, men are to blame. Research highlights a lack of knowledge and effective treatments in this area, often neglected in favor of medical interventions for women.
– The causes and factors influencing male fertility are multiple and complex, including aspects linked to lifestyle, environment, and genetics:
1. Obesity:
A BMI greater than 30 can impair sperm quality by influencing the metabolism of androgens, including testosterone, which affects sperm development and sperm DNA integrity.
– Endocrinological impact:
Obesity, particularly abdominal obesity, causes alterations in the hypothalamic-pituitary axis. In
In obese men, there is a significant reduction in testosterone levels and an increase in estrogen levels, negatively affecting spermatogenesis.
– Dysfunction of Leydig and Sertoli cells:
The cells located in the testicle are affected, contributing to reduced male fertility.
– Testicular warming:
Excess scrotal adipose tissue and abdominal obesity can increase testicular temperature, thereby impairing spermatogenesis and reducing sperm count.
2. Smoking and addictive substances:
Nicotine and cannabinoid receptors in testicular tissue harm sperm quality. Cocaine, in particular, impairs sperm development and motility.
– Effects of nicotine:
Nicotine hurts sperm quality. It can cause an imbalance called oxidative stress, thereby influencing sperm quality and fertilization potential.
– Impact of cocaine:
This substance impairs the development and motility of sperm. The damage caused to sperm by smoking and drug use is only reversible after several months of stopping.
3. Radiation:
It is recommended to avoid keeping cell phones near the scrotum to reduce the risk of radiation-related infertility.
– Mobile phones :
While there is debate over the exact impact of cell phone irradiation on male fertility, experts recommend avoiding keeping cell phones near the scrotum to reduce risks.
– Cancer treatment:
Radiation exposure in cancer treatment, such as chemotherapy, requires fertility preservation strategies, such as sperm freezing or other advanced methods.
4. Infections:
Infections can lead to a lack of fertility or male infertility by altering sperm quality.
Here are the main types of infections impacting male fertility and their effects:
– Sexually transmitted infections (STIs):
Such as chlamydia, gonorrhea, and syphilis. These infections can cause inflammation of the reproductive organs, leading to conditions like epididymitis and prostatitis, which can obstruct the passage of sperm and reduce fertility.
– Urinary tract infections (UTI):
They can spread to the reproductive system and damage sperm-producing structures. Symptoms include pain or a burning sensation during urination and frequent urination.
– Infections of the reproductive system:
Like epididymitis and orchitis, can cause testicular damage and impair sperm production. Prompt diagnosis and treatment are crucial to preventing long-term fertility problems.
5. Exposure to chemicals and environmental products:
Certain chemicals and environmental factors can negatively impact male fertility.
Exposure to chemicals can affect male fertility in several ways:
– Endocrine disruptors:
Made up of several elements such as bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), and paracetamol are endocrine disruptors that can interfere with the normal functioning of hormones, which can lead to fertility problems at men’s.
– Effects on sperm quality:
Exposure to chemicals can reduce sperm count, motility, and morphology, increasing the risk of infertility and difficulty conceiving.
– Hormonal imbalances:
Certain chemicals can disrupt hormonal balance in men, leading to decreased testosterone levels and other hormonal imbalances.
– Perfluorinated compounds:
Used in anti-stain and waterproofing treatments for textiles, food packaging, and certain insecticides, experts suspect that they cause infertility risks for couples and modify sperm morphology.
– Long-term and transgenerational effects:
Distilbene, among other chemicals, has shown adverse effects on fertility and the reproductive system over several generations.
It is advisable to reduce exposure to chemicals to protect male reproductive health. This may include adopting healthier lifestyles, reducing the use of toxic chemicals, and improving environmental monitoring.
6. Genetic factors:
The genetic mutations, such as those affecting the NR5A1 gene, can be responsible for severe forms of male infertility.
– Genetic Mutations:
Specific mutations can cause male infertility. For example, mutations in the CFTR gene are linked to cases of cystic fibrosis and agenesis of the vas deferens, affecting fertility. Other important genes are NR5A1, AURKC, and SBM5, mutations of which can disrupt spermatogenesis.
– Transmission of Mutations:
Certain genetic mutations, such as “de novo” mutations, can appear in an individual without being present in the parents. These mutations can then be passed on to future generations.
– Impact and Treatment:
These genetic anomalies can be treated by assisted reproduction techniques such as in vitro fertilization (IVF) with genetic testing, making it possible to select embryos free of genetic anomalies. Future advances in gene therapies, such as gene editing, could offer targeted treatments for these infertilities.
7. Age:
Male fertility may decline with age, particularly after age 40.
– Quality and Quantity of Sperm:
With age, the quality and quantity of sperm can decrease, affecting sperm motility, morphology, and DNA integrity.
– Genetic Risks:
Older men have an increased risk of genetic abnormalities in sperm, which can increase the risks of birth defects and genetic disorders in their offspring, such as Down syndrome, autism, or schizophrenia.
– Treatment of Age-related Infertility:
Older men facing infertility may turn to assisted reproductive technologies like IVF or intracytoplasmic sperm injection (ICSI). These methods increase the chances of conception even with reduced sperm quality.
Conclusion :
In summary, fertility is a complex and multidimensional field, influenced by genetic factors, age, as well as environmental and lifestyle elements. Understanding these factors is crucial to addressing infertility, and providing couples with valuable information and targeted treatment options. Although medical advances in the field of assisted reproduction offer hope, managing infertility remains an individual and often difficult journey. It is therefore essential to continue research in this area to improve treatment and support options for those facing fertility challenges.
