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Unexplained infertility

Infertility is a pretty stressful problem for loving couples who want to have a baby. One of the most frustrating diagnosis in reproductive medicine is so called “unexplained infertility” which is used to describe a couple who have been trying to conceive for a year or more, and despite undergoing all most modern fertility tests, no reason can be found to explain the infertility. In cases of unexplained infertility no firm strategy and guidelines can be provided and chances for pregnancy are actually not known. Doctors cannot tell about whether conception is ever likely, how much longer it may take, and whether assisted conception should be considered immediately or in the longer term.

It is known that about 10-20% of couples experiencing fertility problems will have unexplained infertility. Although it is hard for a couple to learn why they are infertile, learning that there doesn’t seem to be any explanation for your infertility can be even more difficult.

There are two groups of infertile couples who “suffer” from unexplained infertility:

  • couples who are just unlucky and don’t have any medical and/or biological problems which could be considered as a cause for infertility;
  • couples who most probably have a medical reason for infertility, but infertility cause cannot be discovered due to insufficient medical knowledge or technology.


In most cases the diagnosis of unexplained infertility is based on exclusions of all possible infertility causes. Unexplained infertility can be confirmed only if the following tests demonstrated good results:

Female partner

  • Ovulation is occurring normally (time and sizes) on a monthly basis;
  • Fallopian tubes are open (not blocked) and healthy;
  • Hormone profiles are normal and adequate according to the menstrual cycle days;
  • The lining of the uterus is of adequate thickness according to the menstrual cycle days and ready for implantation on correct time;
  • Endometriosis is excluded (using modern methods);
  • Pelvic adhesions are excluded (using modern methods);
  • Anatomic structures of reproductive organs are normal (absence of pathology, absence of fibroids and polyps);
  • Absence of vaginal infections including STDs;
  • Positive postcoital test.

Unexplained infertility

Male partner

  • Semen analysis is normal – high sperm count and good sperm motility;
  • Absence of pathology in reproductive organs;
  • Absence of infections including STDs.

Both partners

  • Absence of any serious chronic diseases;
  • Healthy lifestyle (excluding drug abuse and
    tobacco abuse)

The exact reason as to why pregnancy is not occurring cannot therefore be explained. The more tests that are performed, the more likely it will be that a reason for your infertility will be found.


Ovulated Eggs

The quality of eggs is very important. In general ovaries can produce eggs every month but not all of these eggs are suitable for fertilization and division. Eggs need to be of the proper shape and size and must contain the right chromosomes to be successfully fertilized and implanted. If the quality of ovulated egg is not perfect, fertilization and implantation could be a problem and the couple could have problems getting pregnant.

Luteinized Unruptured Follicle (LUF) Syndrome

Normal ovulation is a crucial component in fertility. During ovulation, it is possible for eggs to become trapped in the sac that protects them – while maturing, eggs are kept inside of a tiny membrane, called a follicle and when stimulated (by specific hormonal medicine), this follicle bursts to release the egg. The egg then moves into the fallopian tube and the leftover membrane becomes the corpus luteum. Sometimes though, a follicle can become a corpus luteum before rupturing, trapping the egg inside (instead of ovulation). As a result, ovulation never occurs.

Fallopian Tubes

Sometimes, unexplained infertility is actually caused by tiny abnormalities in Fallopian tubes which contain structures that help to sweep ovulated egg inside. The fimbria are finger-like projections located at the ends of each fallopian tube – they grab onto ovaries, helping to coax the egg inside. Both Fallopian tubes also contain cilia, tiny hairs that help to move the egg down into the uterus. Sometimes, there are problems with the fimbria or cilia, which can prevent ovulated egg from being fertilized.

Problems in Luteal Phase

It is well known that the period after ovulation called “luteal phase”of the menstrual cycle. During luteal phase, the corpus luteum begins to produce hormone progesterone which is responsible for uterus preparation – endometrial lining for implantation. Sometimes the level of progesterone could be changed (reduced or increased for several reasons) and as a result, the endometrium doesn’t become properly prepared for implantation.

Immune Problems

In general the immune system is designed to protect body from invading “unknown” and “unexpected” cells and organisms. Immune system is responsible for killing off disease and infection. Sometimes the immune system can be “damaged” and confused (because of strange signals from brain and organs). Changed immune system can start fighting and attack own body cells (eggs). Male partner’s immune system could even be attacking sperm cells, causing them to stick together, become immobilized, or even die.


Different types of infections and especially vaginal infections and also sexually transmitted infections could create problems for normal fertilization and implantation processes. Sometimes infection is not detectible by laboratory tests because these particles exist in such small numbers that they are undetectable through examination.

Weak Sperm

In order to become fertilized, sperm must be able to break through the outer shell of you egg. Sometimes, even healthy-looking sperm cannot break through the egg in order to create an embryo. The quality of spermatozoids is crucial.

Stress and Emotions

Stress and emotions can play a very important role in infertility – important for both partners (females and males). The entire reproductive system and reproductive functions are controlled by the brain. Any stress and/or negative thinking and/or emotional distress can sometimes interfere with the brain’s ability to control the reproduction in couples. For example, the depression has been linked with decreasing of women ability to get pregnant. Unfortunately reproductology experts aren’t exactly sure how or to what degree stress and emotions can play a role in infertility but it is recommended to try to avoid stress and/or use stress management tools. Sometimes just changes in life could have positive influence at psychological component of your fertility – change of house, styles, habits, atmosphere, etc. You might want to think about redecorating your home or office in order to create a more relaxing environment in which to focus on your thoughts and on your body.

Prematurely Aging Ovaries Syndrome (PAO)

It is noted in women after 35. As a woman ages, the number of follicles within the ovaries decreases, causing infertility. PAO occurs when this process happens to younger women, well before menopause.


If you receive a diagnosis of unexplained infertility, there is no reason to give up hope. There is still a good chance that you will get pregnant on your own, without any fertility treatments. In fact, your chances of getting pregnant within three years are over 30%.

For couples with unexplained infertility, treatments such as Follicular tracking, Clomid or Intrauterine Insemination (IUI) could be offered prior to the more invasive treatments such as IVF.

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