In medical terms, infertility is defined as the inability to conceive after 12 months or more of unprotected sexual intercourse. Some 10 to 15% of couples in Switzerland face this problem.

Infertility can be a male as well as a female problem: around 30% of cases affecting a couple are linked to the woman, 30% to the man and 30% to both partners. The remaining 10% relate to fertility problems of unknown origin.

That is why it is important for both partners to be involved in finding the possible causes of infertility and its treatment.

Causes of female infertility

Ovulation problems
The absence of ovulation (anovulation) or ovulation disorders (dysovulation) are the most frequent causes of female infertility. In both cases, no fertilizable egg cell is produced, so no pregnancy can occur. Numerous factors can hinder or prevent ovulation, including polycystic ovary syndrome, thyroid issues, hormone disruption, stress, extreme weight loss or gain, excessive physical activity, etc.

Damaged or blocked tubes
This is the second most frequent cause of infertility in women. The fallopian tubes connect the ovaries to the uterus and are therefore an essential reproductive organ. Their dense musculature and multitude of motile cilia enable the egg to enter the tube at the moment of ovulation and guide the sperm towards it, allowing fertilization to take place. The delicate ciliary mucus can be easily damaged.

In most cases, fallopian tube lesions are the consequence of a sexually transmitted infection but they can also be linked to endometriosis or may be caused by surgery.

Uterine conditions
Sometimes, uterine malformations, adhesions (scar tissue) or uterine fibroids can disrupt embryo implantation, thereby reducing the chances of pregnancy.

Endometriosis is a frequent gynaecological condition in which endometrial cells (the tissue that lines the inside of the uterus that is shed during menstruation) grow outside the uterus. Endometrial cells can implant in other organs. As they multiply, they form ovarian cysts (endometriomas) and bands of fibrous tissue (adhesions) that potentially prevent the release of eggs by the ovaries or the transfer of eggs into the fallopian tubes, thus reducing the chances of pregnancy.

In today’s society, women are waiting increasingly longer before trying for a first pregnancy. This is a significant contributory factor for increased infertility, since the chances of pregnancy decrease with age. In practice, female fertility begins to decline in their mid-30s, or sometimes earlier, and gradually accelerates. At 40 years of age, the chances of becoming pregnant each month are less than 10%. This decline is due to the decrease in the number and quality of egg cells, which is a genetically programmed process.

Causes of male infertility

The most common cause of male infertility is poor quality sperm. Anomalies in the density or motility of sperm cells prevent them from reaching and fertilizing the egg cell.

The causes of poor sperm quality are a matter of debate, with tobacco use, alcohol consumption, obesity, stress and exposure to pesticides and endocrine disruptors, among others, potentially to blame.

Male infertility can be caused by:

  • A problem with blocked ducts, preventing sperm from leaving the testicles
  • An illness (diabetes, cancer treated with chemotherapy and certain liver and kidney diseases)
  • Genetic disorders (an abnormal number of chromosomes or Y-chromosome microdeletions)
  • Chronic or acute inflammation or infection of the testicles
  • Testicular variocele (a group of enlarged veins near the testicles)
  • Sexual disorders (erectile dysfunction or ejaculation problems)
  • Hormonal problems affecting the reproductive system and interfering with sperm production