The dreaded diagnosis: Unexplained

In the wonderful world of infertility there many different diagnosis's- we have been falling into the what I can the "dreaded" diagnosis of unexplained infertility. However there is some science behind the unexplained diagnosis.

Infertility is officially defined as the inability to conceive after one year of sexual intercourse without the use of any contraceptive methods. A systematic and standard evaluation of all couples with infertility usually involves three initial tests:

1. Confirmation of ovulation by History and lab tests.
2. An assessment of the fallopian tubes and the uterus by the use of an x-ray called Hysterosalpingogram (HSG).
3. An assessment of a semen analysis (SA).

If the results of these three tests are normal, and the couple has been trying to conceive for at least one year, the diagnosis of unexplained infertility is made. Of the patients seeking infertility treatment nearly 10 to 15 percent are diagnosed with unexplained infertility. What this means is that even though the initial tests we perform to evaluate ovulation, the fallopian tubes and SA are normal, this couple has difficulty conceiving due to some inefficiency in the process of conception.

Eventually most couples with unexplained infertility get pregnant. The problem may be an inefficiency that can be overcome with time and more attempts at conception. Most patients with unexplained infertility conceive within six to seven years. Perhaps a younger patient can afford the wait, but older patients may not have the luxury of time.

Now, I know that everyone is freaking out when I say six to seven years, now that seems like a really long time. I am 28 right now and my husband is 38 years old, so where I could afford to wait my husband cannot, its not that he couldn't physically have kids when he is older, but why would he want to be 44 when he could be 39? That is why I am so grateful that we have modern medical advances that can help speed up the procedure.

Unexplained Infertility may be a mystery since it assumes that in most cases we do not know what is the cause of infertility. In fact there is often something wrong at a more basic level. For example, it is possible that there is something wrong at the level of the gametes (egg & sperm) and their interaction with each other, or their interaction with the female reproductive organs.

It is also possible to have sperm that appear normal under a microscope,therefore causing the seman analysis to appear normal, however sometimes the sperm is not able to perform the function of fertilization adequately. Furthermore, one can have normal sperm but poor quality eggs that do not fertilize or fertilize at a lower than expected rate. If normal eggs and sperm meet, one can expect a fertilization rate between 60 to 90 percent. The outer shell of the egg, the Zona Pellucida, usually hardens after one sperm enters the egg. It is possible for the outer shell not to allow a sperm to enter, or allow too many sperm to enter the egg. Both these situations result in abnormalities that lead to infertility. There is where ICSI in conjuction with IVF is a miracle, because a single sperm is injected into a single egg causing a much hight fertilization rate.

Once an egg is fertilized, there is an 80 percent chance of cell division. The rate of division of the resulting embryo is also of significance. Usually 48 hours after fertilization, the embryo is between two to four cells (blastomeres). At 72 hours, they are usually between six to eight cells. After five days of growth, they are usually over 120 cells with a fluid cavity in the middle (Blastocyst). If a larger than expected percentage of embryos divide slowly or stop dividing at any stage, this can result in infertility. This is where IVF is helpful because the embroyos that have the correct number of cells are the ones that are transferred back into the uterus, therefore causing a higher probability that one will implant and cause a healthy pregnancy.

There can also be problems with normal attachment or implantation of the embryo once it reaches the uterine cavity. This can be due to the presence or absence of certain important factors needed for implantation at the level of the uterus or the embryo. The outer shell of the embryo can be too hard or thick and not allow hatching of the embryo out of its shell (Zona Pellucida). This can result in a lower chance of implantation. A genetic abnormality with the embryo can lead to infertility. The embryos suspected of having a higher chance of a genetic abnormality are embryos with a higher degree of cell fragmentation (abnormal looking cells in the embryo).

Although, an evaluation of the fallopian tubes, ovulation, and a SA are good initial screening tests, they do not identify all causes of infertility. Unexplained infertility therefore is not one specific diagnosis, but possibly a combination of one or many inefficiencies in the processes of conception.

If you are suffering from unexplained infertility, just remember that some things just take time, and eventually most couples suffering from unexplained infertility will go onto conceive. But remember that with all the medical interventions we can take the guesswork out of a lot of possible issues that you may be having, therefore giving you the best chance of getting and staying pregnant.