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What is infertility? Causes, Symptoms and Diagnosis
On average, it is estimated that infertility could affect between 48 million couples and 186 million people of fertile age all over the world, according to the current data from the World Health Organization. Infertility is the pathology that prevents pregnancy from being achieved or brought to completion. It affects both men and women to the same extent. We talk to Dr. Elena Santiago about what we know as infertility and sterility.
At Vida Fertility Institute we recommend that you go to your specialist if after a year of unprotected sex you do not achieve pregnancy. Moreover, if you are over 35 years old, it is advisable not to wait more than six months of searching.
Differences between sterility and infertility
We often use these two terms synonymously to refer to the impossibility of achieving pregnancy. In reality, they are two different terms that refer to whether or not a pregnancy has already been achieved.
We speak of sterility when patients cannot conceive, while we are referring to infertility when there has already been a pregnancy, but due to some problem it has not been brought to completion, it has been interrupted and a miscarriage has occurred.
How are infertility and sterility diagnosed?
We speak of sterility when patients are unable to conceive. Infertility can be defined as the inability to reproduce. A couple is considered infertile if, after one year of regular sexual intercourse without the use of contraception, they do not achieve pregnancy.
Fertilization of an egg and a spermatozoon is a highly complex process. Each piece of this puzzle has an important role to play in order to fit together and form an embryo. It must travel through the fallopian tubes to the uterus, where it will be implanted to gestate and evolve until it gives birth to the desired baby.
But let’s go back nine months. If, during one of these delicate stages of the process, an alteration occurs, either in the man or in the woman, the result will not be as expected.. Frustration and discouragement will overtake expectations as a result.
That is why a detailed study of each patient leading to an accurate diagnosis that identifies where the problem lies and what is the way forward with the least number of attempts is so important.
There are different tests that allow us to assess your fertility condition. Initially, and to start the process, we need to know everything that has happened until we came to know each other, that is to say, what we know as medical history. Then we will focus on each one of them.
For the study of the woman we need:
- Hormonal study in blood to assess: the AMH (anti-müllerian hormone) with which, along with the follicular ultrasound we can reliably know the number of fertile eggs, FSH (follicle stimulating hormone) that promotes egg production and controls the menstrual cycle, LH (luteinizing hormone) controls the maturation of the follicles and, finally, the level of Estradiol (estrogen that identifies the proper functioning of the ovaries.
- Ultrasound for antral follicle count. With this test we measure how many eggs are present in each ovary.
- Hysterosalpingography (HSG), a test performed to determine that the fallopian tubes are permeable, that is, that they are not obstructed.
For the study of the man we need:
After having a first approach comes the step for more advanced tests that allow us to assess different aspects such as: genetics, immunology, the state of the endometrium, among others.
What are the main causes of infertility and sterility?
As we have already told you in this article, infertility can be both male and female.
Main causes of male infertility:
- Low sperm production or poor sperm quality due to: failure of the testicles to descend, genetic defects, diabetes or sexually transmitted disease infections (chlamydia, gonorrhea, mumps or HIV), varicocele (or enlarged veins in the testicles).
- Ejaculation problems: premature ejaculation, cystic fibrosis, testicular obstruction or injury to the reproductive organs.
Main causes of female infertility:
- Early menopause or when the ovaries stop functioning before the age of 40.
- Ovulation disorders such as hormonal disorders, an example of which is due to polycystic ovary syndrome. Excess of prolactin (hormone that stimulates the production of breast milk). Hyperthyroidism or hypothyroidism (excess or deficit of thyroid hormones). In addition, excessive physical exercise, eating disorders or tumors can also affect ovulation.
- Uterine or cervical anomalies that can obstruct the fallopian tubes and prevent the embryo from implanting in the mother’s uterus (polyps, benign tumors or uterine fibroids).
- Pelvic adhesions or scars that form after infection, appendicitis, endometriosis or surgery.
- Damage or blockage of one or both fallopian tubes such as Hydrosalpinx (accumulation of fluid inside the tubes).
- Endometriosis, or when endometrial tissue grows outside the uterus, affects the function of the ovaries, uterus and fallopian tubes.
There are some common factors of infertility.
- Infertility caused by cancer and its treatment with radiation or chemotherapy.
- Environmental factors such as pesticides, chemicals or radiation, as well as unhealthy lifestyles such as smoking, drinking and drug use.
If I already have one child, can I have problems having a second?
Types of Sterility
As mentioned earlier, although often confused with infertility, sterility specifically refers to the inability to achieve pregnancy, even after one year of unprotected sexual intercourse. Its origin can vary greatly, in both men and women. Knowing the different types is key to guiding diagnosis and treatment effectively.
Causes of Sterility in Women
Female factors can interfere with any stage of the reproductive process—from ovulation to embryo implantation. The most common causes include:
- Hormonal disorders (endocrine factor):
Hormonal regulation issues in the menstrual cycle can cause anovulation, poor egg quality, or premature ovarian failure. These often manifest as irregular cycles, amenorrhea, or low ovarian reserve. - Fallopian tube issues (tubal factor):
Healthy, open fallopian tubes are essential for the egg and sperm to meet. Past infections, surgeries, endometriosis or salpingitis can lead to blockages or adhesions that prevent fertilisation. - Cervical abnormalities (cervical factor):
Malformations, chronic infections, or changes in cervical mucus can hinder sperm movement into the uterus. - Uterine anomalies (uterine factor):
Polyps, fibroids, adhesions, or congenital uterine malformations can interfere with embryo transport or implantation.
Causes of Sterility in Men
Evaluating the male factor is just as important. Based on our clinical experience, up to 33% of sterility cases involve some form of male alteration. The most frequent include:
- Hormonal imbalances (pre-testicular factor):
Dysfunctions in hormones like FSH, LH or testosterone can impair sperm production. - Testicular conditions (testicular factor):
Diseases such as varicocele, orchitis, cryptorchidism or testicular trauma can alter the structure and function of the testes, reducing sperm quality. - Blockages in seminal pathways (post-testicular factor):
Even if the testes produce sperm, it may be obstructed in the vas deferens due to chronic infections or ejaculation issues like retrograde ejaculation or erectile dysfunction. - Poor sperm quality (spermatogenic factor):
Low concentration, mobility or abnormal morphology may make natural fertilisation impossible.
At Vida Fertility, we approach these diagnoses with sensitivity and professionalism, offering effective treatments tailored to each individual situation.
Learn more about fertility check-up
Secondary Infertility: If I already have one child, can I have problems having a second?
Yes, this is known as secondary infertility and it is more common than it seems.
For the most part, the causes may be some of those already described in this article. These may be due to the passage of time and age, or as a result of the first pregnancy, such as a possible pelvic infection or the development of uterine adhesions.
If you have any further questions or would like to speak directly with a fertility specialist, please contact us and we will be happy to help you.
*** You may be interested to read about the age limit for fertility treatments in Spain ***
How can I know if I’m infertile?
This is, without a doubt, one of the most frequently asked questions during consultations. And the answer is not always straightforward, since infertility often does not present obvious symptoms. In most cases, it becomes evident when a couple has been trying to conceive for several months without success.
The first step in detecting infertility is to consult a specialist when:
- More than 12 months have passed with regular unprotected intercourse (6 months if the woman is over 35).
- There are medical histories that could impact fertility (surgeries, infections, hormonal disorders).
- Menstrual cycles are irregular or very painful.
- There have been previous pregnancies, but a new one is not achieved.
At Vida Fertility, we perform a comprehensive evaluation of both the woman and the man to determine the cause and guide the most appropriate treatment.
How to know if a woman is infertile
To evaluate female fertility, we analyze several aspects:
- Detailed medical and gynecological history.
- Hormonal testing to ensure all levels are within optimal ranges.
- Transvaginal ultrasound to assess ovarian reserve via antral follicle count.
- Anti-Müllerian Hormone (AMH) test, a reliable marker of ovarian reserve.
- Hysterosalpingography to check if the fallopian tubes are open.
- Hysteroscopy or laparoscopy in cases where we suspect endometriosis or uterine abnormalities.
As a gynecologist, I often tell my patients: “Knowledge is power.”
Knowing your fertility status allows you to make informed decisions, without wasting more time than necessary.
How to know if a man is infertile
The evaluation of the male partner starts with a simple and highly informative test: the semen analysis (seminogram). This test measures:
- Sperm concentration
- Motility
- Morphology
- Volume, pH, viscosity, and other relevant parameters
In some cases, we also request hormonal analysis, testicular ultrasound, or sperm DNA fragmentation testing, especially when there is a history of miscarriage or persistently low sperm quality.
A key fact: More than 33% of infertility cases in couples have a male origin, so studying the male factor is just as important as evaluating the woman.
FAQs about infertility
How does chemotherapy affect male fertility?
Chemotherapy and radiotherapy can significantly affect male fertility, as they target rapidly dividing cells like those that produce sperm. This can damage both mature sperm and the stem cells (spermatogonia) that generate them, potentially causing temporary or permanent infertility. Additionally, if radiotherapy impacts the brain (hypothalamus and pituitary gland), it can disrupt hormone production needed for sperm formation and lower testosterone levels.
How does chemotherapy affect female fertility?
In women, chemotherapy and radiotherapy can reduce ovarian reserve, especially when radiation is applied to the pelvic area. This increases the risk of premature ovarian failure or early menopause. Age is a crucial factor: younger women are more likely to retain viable eggs. If the uterus is affected, embryo implantation may be compromised, leading to miscarriages or premature births. These treatments can also alter hormonal balance, causing changes in menstrual cycles.
What if I don’t get pregnant after 12 months?
If you’ve been having regular, unprotected sex for a year without achieving pregnancy, it’s highly advisable to consult a fertility specialist.
For women over 35, the timeframe shortens—medical help is recommended after six months of unsuccessful attempts.
If you recognize yourself in any of these situations or have been trying to get pregnant for a while, we invite you to take the first step.
At Vida Fertility, we’re here to listen, support, and guide you with the best medical and human team.
Book your first consultation with Vida Fertility now and find the best path to achieve your pregnancy. We’re here for you.
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