Possible Explanations For Unexplained Infertility

Unexplained infertility isn’t a magical condition. There is a reason; we just don’t know what it is.

While experts have exponentially improved their fertility knowledge over the past several decades, there is much we still don’t know.

There are also things we know may cause problems, but don’t have a way to measure or evaluate yet. (Or the only way is invasive and expensive, more on that below.) 

Here are some possible explanations for unexplained infertility:

Undiagnosed underlying (non-reproductive) medical problem:

We don’t yet completely understand how poor health impacts fertility in more subtle, not yet measurable ways. But we are learning more and more.

For example, untreated Celiac disease may in some cases of unexplained infertility. Various research studies have found that Celiac disease is diagnosed two to six times more frequently in women with unexplained infertility compared to the general public.

Other underlying conditions that may cause infertility include diabetes, an undiagnosed thyroid disorder, and some autoimmune illnesses.

Mild endometriosis:

Severe endometriosis is more likely to cause fertility problems that are noticeable even without laparoscopy. For example, endometrial cysts may interfere with ovulation or even cause fallopian tube blockages.

Mild endometriosis may not interfere with ovulation or clear passage of the egg. It may also have no obvious symptoms.

Endometriosis might be behind some unexplained infertility cases. However, experts don’t agree on whether mild endometriosis can cause infertility, and if yes, whether laparoscopic surgery for diagnosis and reprove endometrial deposits is beneficial.

The interaction between the vaginal environment and sperm:

After ejaculation, sperm must make their way out of the semen and into the cervical mucus. Then, they must swim up from the vagina, into the cervical opening, and eventually into the uterus.

Sometimes, there may be problems during that transition period, from the semen, into the cervical mucus, and up the cervix. For example, there may be antibodies in the cervical mucus or even the semen that attack the sperm.

This is known as hostile cervical mucus. How to effectively diagnosis this problem isn’t clear, leaving cases like these frequently unexplained.

Poor egg quality:

We have tests to determine if you’re ovulating, and testing to get a general idea of whether there is a relatively good quantity of eggs in the ovaries.

But there is no test to determine whether the eggs are good quality. Poor quality eggs may be caused by age, an underlying medical condition, or some yet unknown cause.

Poor egg quality may be diagnosed during IVF treatment. After egg retrieval, eggs will be examined under a microscope.

Poor sperm quality:

Some kinds of poor sperm quality are recognizable. For example, poor sperm shape (also known as morphology) may cause fertility problems. Poor sperm motility (or movement) may also cause infertility.

But these are diagnosable. They can be seen during a semen analysis.

There may be issues related to sperm quality that are not obvious during semen analysis.

For example, the sperm may have poorer quality DNA. These DNA issues increase as a man ages, which is why children of older fathers are at an increased risk for certain birth disorders and mental health problems.

Poor sperm quality may be diagnosed during IVF treatment. If good-looking sperm can’t seem to fertilize healthy looking eggs, this may indicate problems with egg or sperm quality.

Problems with the endometrium: 

You can have a healthy cervical environment, healthy eggs, and healthy sperm…but if the resulting healthy embryo can’t impact into the endometrium, we have a problem.

There is so much unknown about possible fertility problems related to the endometrium.

For example, one study found that a newly discovered virus is more commonly found in the endometrial tissue of women with infertility than in women with proven fertility. But how to diagnosis and treat this problem isn’t known.

Luteal phase defects also fit under possible problems with the endometrium and could be the answer for some cases of unexplained infertility.

Problems with a fertilized egg developing to a healthy embryo:

Let’s say we get a healthy looking egg and sperm, and they become an embryo. Next, the cells inside the embryo my divide and grow to eventually form a fetus.

Sometimes, this goes wrong. This is another problem that may be diagnosed during IVF treatment since embryos are monitored for normal cell division.

Portrait of thoughtful beautiful woman with man in background at home

Some factor yet unknown to fertility experts:

It may be that the cause of your unexplained infertility is completely unknown to medical professionals at this time.

We don’t know everything there is about fertility yet.


Nothing may be seriously wrong:

Some couples with unexplained infertility will conceive without any treatment help within one to two years of diagnosis. No one knows why or what was wrong, but it happens.

A healthy, fertile couple has about a 30% chance of conceiving in any given month. Notice that the odds are not 100%. They aren’t 100% for anyone.

It could be you have a very subtle fertility problem, but not so much that you can’t conceive on your own with more time. (This is sometimes called subfertility.)

It could be you and your partner have had seriously bad luck.

It’s frustrating, but it’s a possible explanation for those that have been trying to conceive for less than two to three years.

Related Posts

Make sure you grab a copy of my FREE guide Trying To Conceive Language & my FREE Self-Care Mini Course. You can access either one by clicking on the title. These are packed full of information that you can begin implementing today to put yourself one step closer to getting pregnant, naturally.

If you’re looking for a group of like-minded women with which to share your fertility wellness journey, be sure to check out my Whole Body Fertility & Wellness Facebook group today!

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