Why can’t I get pregnant? Signs, causes and fertility tests

Published: 15 September 2022|Last updated: 20 September 2022|About Assisted Reproduction.|

For many couples, the impossibility of fulfilling the dream of having children can be a real problem that leads many women to ask themselves “why can’t I get pregnant?” If this is your case, in this article we will try to advise you by providing you with information and possible options.

Couples sometimes assume that they will get pregnant quickly. However, it may take several attempts. It is thought to be normal for a healthy couple to try to conceive for up to a year, even for a woman under the age of 35 and in good health. In fact, only a little more than a third of healthy couples actually achieve conception within the first month of trying. On the other hand, one in six couples have trouble conceiving, which encompasses a wide variety of causes affecting both male and female fertility. Some of these can be solved with a simple lifestyle change, others need medical intervention to increase fertility.

Often, the most important thing is to find the reasons that may be affecting conception. That is why, below, we will go over some of the most common causes or signs of female and male infertility and how to deal with them from a professional point of view.

How long does it take to get pregnant naturally?

When a couple starts trying for a baby, they hope and expect that pregnancy will come as soon as possible. Over half of women expect to get pregnant within the first six months, and younger women expect it to happen even sooner. However, in a 2013 study of more than 1,400 women who were planning their pregnancy, 44% found that it took longer than expected.

A common and easily rectified factor is choosing the right time for intercourse. So much so that up to half of couples may be trying to conceive at the wrong time because they do not know when the 3 most fertile days are.

Symptoms, signs and possible causes of infertility

When talking about possible causes of infertility or its symptoms, we need to remember that the likelihood of pregnancy depends on age. Specialists point out that a woman’s most fertile stage of life is between the ages of 20 and 30, after which her reproductive capacity begins to progressively decrease.

So, if you are wondering why you are not getting pregnant if you don’t have any problems, the reason may range from a lower chance of getting pregnant due to age, to trying to conceive at the wrong time, as conception is only possible in the days before and during ovulation and it is important that intercourse takes place at that time. In any case, you should not worry about age, as more and more women are deciding to become mothers from the age of 35 onwards, and there are numerous assisted reproduction treatments designed to help increase the chances of being able to get pregnant.

If you are interested in finding out more about your fertility, we recommend a reproductive counselling consultation at Eugin, where tests could be carried out to assess your personal fertility and that of both partners. As for other factors or signs that may reduce the chances of pregnancy or fertility, the following are the most common causes.


Eating low-quality and highly processed foods contributes to deficiencies of nutrients, vitamins and micro- and macro-elements, such as magnesium, iodine, fluoride, zinc and selenium. The latter two play a major role in the proper functioning of the reproductive system, not only in women, but also in men.

In fact, in men, one of the main causes of male infertility is because of damage to spermatozoa and their genetic material due to oxidative stress. This is caused by too high a level of reactive oxygen species produced by leukocytes and abnormally constructed male reproductive cells. Excess hydrogen peroxide causes DNA damage, leaky cell membranes and sperm cell death. In other words, oxidative stress alters sperm motility, reduces sperm count, worsens morphological parameters and decreases sperm activity.

Weight problems

Closely related to the previous cause is the question of weight. An overweight woman may have trouble conceiving because of hormonal imbalances. An overweight man may also have a low sperm count, erectile difficulties, hormonal problems, and sometimes other health problems related to obesity that could make conception difficult.

In these cases, we recommend being as close as possible to the ideal body mass index, as this can increase the chances of getting pregnant. This is why the opposite extreme to being overweight can also be problematic. In the case of women, too low a weight can lead to failure to ovulate properly, affecting their fertility and chances of pregnancy.

In short, and as we have already seen in our article dedicated to the ideal weight for IVF, weight can be a key factor in your fertility.


Stress is a condition that can affect the sufferer mentally and physically. For women, when they are stressed, cortisol (the stress hormone) levels are very high and can affect their ovulation, either preventing it or altering their cycles. For men, stress can lead to lower sperm counts.

Dealing with stress, especially when you can’t seem to distance yourself from the reason why you are stressed, requires regular exercise, good sleep habits, diet and often psychological counselling. In any case, while high stress is never healthy, if it does not affect your cycles or sex life, it shouldn’t prevent you from getting pregnant.

Problems with ovulation or fallopian tubes

Ovulation is the release of the egg into the fallopian tube, which is where conception takes place. If a woman doesn’t ovulate, she cannot get pregnant naturally. Ovulation can be affected by many different circumstances: polycystic ovary syndrome, being underweight, hormonal imbalances (e.g. thyroid problems), low ovarian reserve. The signs that this may be happening are irregular cycles with irregular bleeding.

Although it is not essential to schedule intercourse around ovulation, it can be useful to have sex every other day during the ovulation period (there is nothing to tell us about egg quality).

But if you’re wondering why you’re not getting pregnant if you’re ovulating properly, there may also be another reason. One reason is a blockage in the fallopian tubes, which prevents the sperm from reaching the egg. Sperm must pass from the vagina through the uterus to the fallopian tube to meet the egg, but if that entrance is closed, the encounter doesn’t happen. This obstruction may be due to pelvic inflammatory disease, endometriosis, previous surgery, or a prior Chlamydia infection. In such cases, the solution requires medical help.

Low sperm quality

While we have already mentioned some habits that can lower sperm count or lead to poorer sperm quality, there are other practices that can affect sperm quality and lead to asthenozoospermia, erection problems or even ejaculation problems. Among the most common recommended preventive measures are not smoking, not taking drugs and limiting alcohol consumption, as well as avoiding taking testosterone supplements to build muscle. Excessive heat in the testicular area (e.g. among cooks or professional drivers) can also lead to a drop in sperm production. Excessive exercise (e.g. cycling) can also be detrimental.

In some cases, however, it may be caused by a birth condition or due to previous testicular damage. If this is the case, medical care is necessary, as male infertility rarely shows symptoms and is usually diagnosed with a seminogram or semen analysis, where the practitioner will check the quality of the semen and sperm. At Eugin, the first visit includes this test free of charge, so that you can settle your doubts.

Other medical problems

Apart from the above-mentioned causes, there are other medical problems related to difficulties in getting pregnant. For example, anxiety and depression (antidepressants can reduce the chances of pregnancy), undiagnosed diabetes or gluten intolerance. That is why, having reached this point, experts recommend that you see a fertility specialist for a personal consultation.

But if I’ve already had a child… why can’ t I get pregnant now?

Age affects both egg quality and quantity. With regard to women, they are born with a certain number of eggs, which they release throughout their fertile life. This means that the older the woman is, the fewer eggs she has, and the lower their quality. The same happens if the man is over 40 with regard to the quality of his sperm.

Both circumstances could explain why you are not getting pregnant, even if you already have a child and have ruled out infertility. Therefore, if you are over 35, have a child and have been trying to get pregnant for more than six months or a year without success, it may be secondary infertility. In these cases, a good option to become a mother is to turn to in vitro fertilisation.

Female fertility tests to find out why I’m not getting pregnant

If your problems in getting pregnant persist, the best way to find out the cause of these difficulties is to consult a gynaecologist or a specialist in assisted reproduction. There are several tests to determine the causes of female infertility, ranging from a transvaginal ultrasound (to rule out problems in the uterus or fallopian tubes) to a hysteroscopy (which allows you to have a look inside the uterus and take samples). These are some of the most common tests:

  • Transvaginal ultrasound
  • Anti-Müllerian hormone (AMH)
  • Hysterosalpingogram
  • Hysteroscopy
  • Endometrial biopsy
  • Karyotype test

In some cases, 10% of couples are unable to find the reason for their failure to conceive, but that doesn’t mean that there aren’t other ways to achieve conception, as we have seen. So, if you’ve been trying for more than a year (or six months if you’re over 35), there are several options for assisted reproduction treatment that can help you. Contact us for a free evaluation on your first medical visit at Eugin.


Gnoth C., et al. Hum Reprod. (2003) 18 (9): 1959–1966

Johnson SR, Pion C. Multi-national survey of women’s knowledge and attitudes towards fertility and pregnancy

Robinson J. i Ellis J. Current Medical Research and Opinion. (2007) 23: 301–306

Johnson SR., et al. Home ovulation tests and stress in women trying to conceive: a randomized controlled trial. 26: i236

Would you like to know more about fertility treatments at Eugin?

Choose your clinic

Madrid Barcelona
✓ Valid

* In order to properly process your request, we need all fields to be filled

In Eugin we take your privacy very seriously, and of course, strict compliance with the Data Protection Law. The information is only used in the context of your treatment. Our computer system has the most secure encryption protocols, and complies with the demanding ISO / IEC 27001: 2013 standard.