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Infertility causes

The general understanding of the word “INFERTILITY” is that despite regular sexual intercourse, without any form of contraception, a couple is unable to get pregnancy. Infertility means not being able to get pregnant after one year of trying OR six months, if a woman is 35 or older. Women who can get pregnant but are unable to stay pregnant may also be infertile (see miscarriage).

It is estimated that one in six couples face difficulties in conceiving. If you have had unprotected regular sex for more than 12 months (or six months – if you are over 35) and are still not pregnant, you should start thinking about possible causes for your infertility.
There are many different causes of infertility. It is well known that in 35% of cases the infertility cause will be found in female partner; in 35% of cases male factor is the main cause of infertility; in approximately 20% of couples there may problems in both partners and in approximately 10% of cases no problem will be found and yet infertility persists (“unexplained infertility”).


1. Ovulation disorders

Infertility is most commonly caused by problems with ovulation – main cause of infertility in women is anovulation (absence of ovulation). Women ovulate most effectively in their late teens and early twenties. By age 35-38, most women may experience a decline in the ability to ovulate effectively.

Ovulation problems can be discovered during several types of hormonal dysfunctions:

  • Any dysfunction in menstrual cycles – irregular periods, amenorrhea, oligomenorrhea, menstrual bleedings, light periods, uterine bleedings, etc. – all can be a reason for absence of ovulation;
  • Polycystic ovary syndrome (PCOS), a condition that makes it more difficult for ovaries to produce mature egg;
  • Endometriosis – when endometrial tissue grows outside the uterus (on tubes, ovaries, other organs) – this can cause infertility because the new growths form adhesions (sticky areas of tissue) or cysts (fluid-filled sacs) that can block or distort the pelvis. These make it difficult for an egg to be released and become implanted into the womb. Endometriosis can cause infertility because it can disturb the way that a follicle (fluid-filled space in which an egg develops) matures and releases an egg;
  • Premature ovarian failure, where a woman’s ovaries stop working properly before she is 40;
  • Hyperandrogenemia (increased androgens – male hormones) developed because of different conditions including PCOS, tumors and adrenal diseases;
  • Thyroid problems – abnormalities of the thyroid gland – both hyperthyroidism (overactive thyroid glands) and hypothyroidism (underactive thyroid glands) can prevent ovulation;
  • Hyperprolactinemia – overproduction of prolactin (a hormone leading to breast milk production) – hyper production of prolactin can stop periods and ovulation;
  • Chronic (long-term) conditions – some chronic conditions, such as cancer, or AIDS, can prevent ovaries from releasing eggs;
  • Cushing’s syndrome, a rare hormonal disease that can prevent ovaries from releasing an egg.

Egg quality – sometimes even after ovulation women cannot conceive because of eggs’ poor quality. If the egg is damaged or has a chromosomal abnormality it may not result in a pregnancy. This is more common as the woman gets older (over 35).

2. Cervical infertility

Infertility causes?

Cervical factor of infertility could be difficult to discover. Cervical infertility involves inability of the sperm to pass through the cervix due to damage of the cervix. Main reasons for cervical infertility could be:

  • inadequate or inhospitable cervical mucus;
  • cervical narrowing or “stenosis”;
  • cervical infections during sexually transmitted diseases (SYDs) – chlamydia, gonorrhea, or trichomonas, as well as mycoplasma hominis and ureaplasma urealyticum;
  • immune attack of sperm or “sperm allergy”.

3. Uterus and fallopian tubes
Uterus and fallopian tubes are very important for fertilization and implantation. Successful pregnancy depends upon the sperm being able to reach the egg and the fertilized egg reaching the womb, to implant safely in the wall of the uterus. Any problems in uterus and/or tubes can prevent and/or interrupt possible pregnancy. If there are blockages in the fallopian tubes, the chances of a successful pregnancy will be greatly impeded. Blocked tubes could be a main reason for female infertility due to pelvic inflammatory disease (PID), sexually transmitted infections (STDs) such as clamydia, infection from the previous birth and blockages from previous surgery (following ectopic pregnancy or sterilisation procedures).
Uterus problems can cause infertility at different stages of possible pregnancy.
Pelvic causes include any disruption of the normal pelvic anatomy – Scar tissue or “adhesions”; Endometriosis;Blocked, scarred, or distorted fallopian tubes;Benign tumors (fibroids) of the uterus.
Uterine causes include thin or abnormal uterine lining; anatomic problems (polyps, uterine fibroids, abnormal shape of the uterus, septum or “dividing wall” within the uterus).

Infertility causes

4. Medicines and drugs
The side effects of some types of medication and drugs can affect female fertility:

Non-steroidal anti-inflammatory drugs (NSAIDs). Long-term use, or a high dosage, of NSAIDs, such as ibuprofen or aspirin, can make it more difficult for you to conceive.
Chemotherapy. The medicines that are used for chemotherapy (a treatment for cancer) can sometimes cause ovarian failure, which means that your ovaries will no longer be able to function properly. Ovarian failure can be permanent.
Neuroleptic medicines are antipsychotic medicines that are often used to treat psychosis. They can sometimes cause missed periods or infertility.
Spironolactone is a medicine that is used to treat heart failure, and can cause irregular periods and infertility.
Illegal drugs such as marijuana and cocaine can seriously affect your fertility, making ovulation (the monthly cycle where an egg is released from the ovaries) more difficult. Drugs may also adversely affect the functioning of your fallopian tubes.

5. Age
Infertility in women is also linked to age. Unfortunately women fertility is decreasing after 35 – the biggest decrease in fertility begins during the mid thirties. For women who are 35, 95% will get pregnant after three years of having regular unprotected sex. For women who are 38, only 75% will get pregnant after three years of having regular unprotected sex.
Many women are waiting until their 30s and 40s to have children. In fact, about 20 percent of women in the United States now have their first child after age 35. So age is a growing cause of fertility problems. About one-third of couples in which the woman is over 35 have fertility problems.
Aging decreases a woman’s chances of having a baby in the following ways:

  • Her ovaries become less able to release eggs.
  • She has a smaller number of eggs left.
  • Her eggs are not as healthy.
  • She is more likely to have health conditions that can cause fertility problems.
  • She is more likely to have a miscarriage.


Low sperm counts, abnormal sperm morphology (shape), and low sperm motility are usually asymptomatic conditions to most males. Most cases of low sperm counts are “idiopathic” or unexplained. Some cases are associated with a swollen varicose vein in the scrotum, called a varicocele.
Some simple abnormalities may be improved by reducing stress, reducing heat to the genitals (eg. avoidance of tight clothing, saunas or hot tubs), or by changing harmful lifestyle habits (avoiding tobacco, alcohol, or drugs such as marijuana). Short term illnesses, significant stressful periods, and some medications may temporarily affect sperm counts.

1. Semen

Abnormal semen (the fluid containing sperm that is ejaculated during sex) is the most common cause of male infertility. Abnormal semen accounts for 75% of male infertility cases. Some possible reasons for abnormal semen are listed below.

  • Decreased number of sperm. You may have a very low sperm count, or no sperm at all.
  • Decreased sperm mobility. If you have decreased sperm mobility, it will be harder for your sperm to swim to the egg.
  • Abnormal sperm. Sometimes sperm can be an abnormal shape, making it harder for them to move and fertilize an egg.
  • Many cases of abnormal semen are unexplained, but there are several factors that can affect semen and sperm.
  • Movement of the sperm – this may be caused by the shape of the sperm. Sometimes injuries or other damage to the reproductive system block the sperm.

Sometimes a man is born with the problems that affect his sperm. Other times problems start later in life due to illness or injury. For example, cystic fibrosis often causes infertility in men.

2. Testicles
The testicles are responsible for producing and storing sperm. If they are damaged, it can seriously affect the quality of your semen. This may occur if you have, or have had in the past, any of the following – an infection of your testicles, testicular cancer, testicular surgery, a congenital defect (a problem with your testicles that you were born with), undescended testicles (when one or both of your testicles has not descended into the scrotum), trauma (injury) to your testicles and a lump in your testicles.
Varicocele also could be a reason for male infertility – this happens when the veins on a man’s testicle(s) are too large. This heats the testicles. The heat can affect the number or shape of the sperm.

3. Absence of sperm
Your testicles may produce sperm, but it may not reach your semen. The absence of sperm in your semen is known as obstructive azoospermia. This could be due to a blockage in one of the tiny tubes that make up your reproductive system, which may have been caused by an infection or surgery (Sterilisation).

4. Ejaculation disorders
Some men experience ejaculation problems that can make it difficult for them to ejaculate. Other ejaculation problems include – retrograde ejaculation, where semen is ejaculated into your bladder OR premature ejaculation, where ejaculation occurs too quickly

5. Hypogonadism
Hypogonadism is an abnormally low level of testosterone, the male sex hormone that is involved in making sperm. This could be due to a tumor, taking illegal drugs or Kallman’s syndrome (a rare disorder that is caused by a faulty gene).

6. Medicines and drugs
Certain types of medicines can sometimes cause infertility problems:

Sulfasalazine, an anti-inflammatory medicine used to treat conditions such as Crohn’s disease (inflammation of the intestine) and rheumatoid arthritis (painful swelling of the joints). Sulfasalazine can decrease the number of sperm, but its effects are only temporary and your sperm count should return to normal when you stop taking it.
Anabolic steroids, which are often used illegally to build muscle and improve athletic performance. Long-term use, or abuse, of anabolic steroids can reduce your sperm count and your sperm mobility.
Chemotherapy. The medicines that are used in chemotherapy can sometimes severely reduce your production of sperm.
Herbal remedies. Some herbal remedies, such as root extracts of Tripterygium wilfordii (a Chinese herb), can affect the production of sperm or reduce the size of your testicles.

7. Alcohol
Drinking too much alcohol can damage the quality of your sperm. Guidelines published by the National Institute of Clinical Excellence (NICE) state that if men follow the Department of Health’s recommendations of drinking no more than three to four units of alcohol a day, it is unlikely that their fertility will be affected. However, drinking more than this could make it difficult to conceive.


In approximately 10-20% of couples both partners have a problem which is contributing to infertility. This term is also used if the man or woman has more than one problem.


Approximately 10% of infertile women suffer from unexplained infertility. This simply means that the commonly performed tests to diagnose the cause of infertility are all normal and do not define the reason for infertility.

INFERTILITY CAUSES affecting infertile couple

As well as factors that specifically affect a man or a woman’s fertility, there are also a number of factors that can affect fertility in both men and women. These are outlined below.

1. Weight
Being overweight, or obese, reduces both male and female fertility. In women, being overweight can affect ovulation. Being underweight can also have an impact on fertility, particularly for women, who will not ovulate if they are severely underweight.

2. Sexually transmitted infections (STIs)
There are several sexually transmitted infections (STIs) that can cause infertility. For example, chlamydia can damage the fallopian tubes in women, and cause swelling and tenderness of the scrotum (the pouch containing the testes) in men.

3. Smoking
As well as affecting your general and long-term health, smoking can also adversely affect fertility.

4. Occupational and environmental factors
Exposure to certain pesticides, metals, and solvents can affect fertility in both men and women.

5. Stress
If either you or your partner is stressed, it may affect your relationship. Stress can reduce libido (sex drive) which in turn can reduce the frequency of sexual intercourse. Severe stress may also affect female ovulation and limit sperm production.
(information used from NHS choices – //

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