Sterility or Infertility: Are they the same or are there any differences?

By Babygest Staff
Last Update: 03/17/2020

Both infertility and sterility involve the absence of a full-term pregnancy, that is, they prevent a couple from having a child naturally. For this reason, many people wonder whether these are two identical or different concepts.

The definition of sterility and infertility is not the same according to the World Health Organization (WHO), although when talking about fertility problems they are used as synonyms. In this article, we will, therefore, clarify the confusion between the two terms.

Is sterility and infertility the same thing?

The terms sterility and infertility do not have the same meaning, so they are different concepts. It is not the same to say that a person is sterile as a person is infertile.

Sterility refers to the inability to have offspring due to problems in fertilization, that is, caused by the impossibility of the egg and sperm coming together to give rise to the embryo.

Infertility, on the other hand, indicates the inability to carry a pregnancy to term, i.e. the absence of birth despite conception having taken place.

It should be noted that in both cases (sterility and infertility) pregnancy is not achieved. However, infertility comes a little closer. In cases of sterility there is not even fertilization; while in cases of infertility, the embryo is created and there may even be early embryonic development, but birth does not occur.

However, on many occasions, both concepts are mixed, since there is often talk of the difficulty that a couple has in achieving a gestation.


Sterility can occur for different reasons that affect men and/or women. In addition to the factors that cause male and/or female sterility, other aspects can cause problems in achieving a gestation. In these cases, it is said that there is sterility of unknown origin.

Causes of female sterility

There are 30% of cases in which the problems in achieving a pregnancy are due to problems in the woman. Among the most common female sterility factors are:

Disorders of ovarian function.
Usually due to failure of the endocrine system, either by default or by an excess of one of the hormones that regulate reproductive function. When these situations occur, the woman will suffer from anovulation, ovarian failure, early menopause, etc. Also, the ovarian factor refers to poor oocyte quality.
Alterations in the fallopian tubes
make it difficult for the egg and sperm to meet.
Cervical Factor
either by functional or anatomical alterations of the cervical canal that prevent the entry of sperm. This occurs when polyps, endometriosis or as a result of surgery appear.
Uterine Factor
by the presence of fibroids or malformations, as well as endometrial alterations that can cause problems for the union of the gametes. Besides, these types of factors can encourage miscarriages.

These abnormalities can also be a reason for infertility and therefore a full-term pregnancy will not be achieved. Each of the above factors is essential for a woman to become pregnant.

Causes of male sterility

In relation to the causes that give rise to male sterility, the following is usually classified:

Endocrine or pretesticular factor
alterations related to the release of hormones involved in sperm production.
Testicular factor
problems in the testicles due to trauma, hydrocele, varicocele, cryptorchidism...
Post-Testicular Factor
sexual impotence, retrograde ejaculation, obstruction of the sperm ducts, infections, etc. These alterations make it difficult for sperm to escape, even if their production is not altered.
Sperm factor
is the most common cause of male sterility. Sperm count, low motility, or abnormalities in sperm structure are some of the things that can make it difficult to get pregnant.

All these factors can also cause infertility in men, as we have discussed with the causes of female sterility.


When a couple has infertility problems, the encounter between the egg and the sperm takes place and the embryo is formed. However, the result is not going to be the birth of the baby.

Therefore, even if fertilization has taken place, there are numerous factors that can alter the correct evolution of the pregnancy. Among the factors that prevent a pregnancy from being carried to term are:

  • Implantation failures: the embryo forms but fails to implant in the maternal endometrium.
  • Miscarriage: Pregnancy stops at some point in fetal development
  • Ectopic pregnancy: the embryo implants but outside the uterine cavity, preventing normal development.

All these alterations can occur for different reasons: immune disorders, genetic alterations, infections, uterine anomalies, etc.

Assisted procreation, as any other medical treatment, requires that you rely on the professionalism of the doctors and staff of the clinic you choose. Obviously, each clinic is different. Get now your Fertility Report, which will select several clinics for you out of the pool of clinics that meet our strict quality criteria. Moreover, it will offer you a comparison between the fees and conditions each clinic offers in order for you to make a well informed choice.

Solutions for sterility and infertility

When a couple has been having sex regularly for more than a year and does not get pregnant, it is time to visit a specialist. He will study both partners to determine the origin of the problem.

Assisted reproduction can solve both sterility and infertility problems. Nowadays, artificial insemination or an in vitro fertilization process makes possible a gestation in those people who suffer from some problem that affects their fertility.

When fertility problems are serious and you cannot use your gametes (eggs and sperm) it will be necessary to use eggs and/or donor sperm. It should be noted that this type of treatment has a higher cost than using one's eggs, but its success rates are high because the egg and sperm donors are young and healthy people.

FAQs from users

To what extent do lifestyle factors affect fertility?

By Dr. Joel G. Brasch (gynecologist).

Whether you're thinking about getting pregnant or have already been trying, it's never too early or too late to evaluate your lifestyle choices. Starting healthy habits or getting rid of bad ones can improve your overall health. And some lifestyle changes may promote fertility in both you and your partner. For example, smoking cessation, reducing alcohol consumption, eliminating street drugs, practicing safe sex, avoiding overheating (male), limiting caffeine intake, and exercising regularly.

What is the difference between primary and secondary sterility?

By Andrea Rodrigo (embryologist).

Primary sterility is when a couple has never achieved pregnancy and secondary sterility when, after having already had a child, the couple does not achieve the second pregnancy.

The same applies to infertility. Primary infertility means that the first pregnancy is not successful, while secondary infertility means that, after the birth of a first child, the pregnancy of the second ends in abortion or any other abnormality that prevents the development until delivery.

Is the lack of uterus a problem of sterility or infertility?

By Marta Barranquero Gómez (embryologist).

The absence of a uterus is a cause of both sterility and infertility. First, it is a sterility problem since, without a uterus, natural fertilization is not possible.

However, it is also a problem of infertility because, even if in vitro fertilization takes place, i.e. in the laboratory, the embryo created could not develop, due to the lack of a uterus.

What is idiopathic sterility?

By Andrea Rodrigo (embryologist).

The term idiopathic sterility refers to unexplained fertility problems. Despite the tests and analyses carried out on the couple, it is not possible to determine the exact cause of why the fertilization of the egg does not happen.

Does chemotherapy cause sterility or infertility?

By Andrea Rodrigo (embryologist).

Chemotherapy can cause sterility as it affects the eggs and sperm. Therefore, if this oncological treatment prevents the development and maturation of the gametes, fertilization cannot occur and, therefore, we are dealing with a case of sterility.

Is sterility hereditary?

By Andrea Rodrigo (embryologist).

Sometimes sterility and infertility can be caused by genetic alteration, so it may be inherited. It can also happen that, although a certain genetic alteration is not inherited, the fact that a parent has had fertility problems can be a risk factor for being sterile. The predisposition of the child to suffer sterility or infertility may be increased even though the cause is not directly a specific genetic alteration.

In any case, it will depend on each situation and the origin of the problem to conceive.

Suggested for you

Several reasons prevent a gestation from taking place naturally, but patients in this situation have solutions to achieve their desire to become parents. If you are interested in having more information about it, we invite you to continue reading the following article: Sterility and inability to get pregnant: causes and possible solutions.

To determine whether the sterility is due to a female cause, the woman must undergo various studies. If you want to learn more about this topic, we recommend you visit the following article: What are female fertility tests?

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