By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 12/02/2014

Couples that wish to have children and can’t, may suffer from alterations in fertility. After visiting the assisted reproduction clinic and performing the appropriate tests, the causes of sterility will be pointed out.

One of the main factors that must be taken into account, when it comes to finding out the causes of the infertility, is to discover which member of the family has problems, that, to discover if the difficulty in conceiving is due to female or male infertility. Both types of sterility have an incidence of 30%.

It can also happen that both members of the couple have fertility problems. In this case we speak of a mixed cause sterility, which occurs in 25% of cases.

Causes of infertility

Female sterility

When we talk about female infertility, the problem can be caused by several factors. We can find the following alterations in women:

  • Ovarian factor: which may be caused by alterations in ovulation or by eggs of bad quality.
  • Tubal factor: problems in the Fallopian tubes may complicate or prevent the descent of the egg and the passage of the spermatozoids.
  • Cervical factor: which refers to the cervix. This kind of alterations complicates and may even prevent the ascent of the sperm to the uterus.
  • Uterine factor: presence of muscular tumors, uterine adhesions, uterine malformations, or a badly developed endometrium may be considered as alterations in the uterus.

Another cause of infertility may be related to the immunological system of the woman, which may attack the spermatozoa of the man, producing immunological sterility. A woman may have this problem with a partner and not with another.

Male sterility

The same happens with male infertility, which can be caused by several factors:

  • Pre-testicular factor: due to hormonal alterations, the testicles don’t developed completely or can’t accomplish their function.
  • Testicular factor: problems in the testicles, which may be congenital (ever since birth) or due to any later cause.
  • Post-testicular factor: alterations in sperm ducts, sexual impotence or any type of urinary infection.
  • Spermatic factor: it includes any problem related with the spermatozoa.

Sterility without cause

When the cause of infertility is not known we speak of idiopathic infertility or unexplained infertility. It occurs in 15% of the cases of infertility and despite several relevant tests , no problems that might explain why the couples can’t conceive is found.

Finding out the sterility cause

This doesn’t mean that there’s no alteration in the couple, it means that no alteration has been detected by the tests that have been performed. Some diagnoses are extremely complex and, with the tests available, the cause can’t be determined, though this doesn’t prevent a reproductive treatment to be started.

Improve fertility

To improve fertility it’s recommended to have healthy habits: a balanced diet and regular exercise can be most helpful.

The consumption of tobacco and alcohol should also be eliminated or reduced, since several studies relate it with a decrease in fertility in men and women, and the same happens with any kind of drugs.

In order to achieve pregnancy, several factors must be taken into account, and having healthy habits may make a big difference.

Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information