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Unexplained Infertility

Unexplained infertility facts

  • Unexplained infertility is exactly what it sounds like: no clear reason has been identified for why a couple or individual cannot conceive.
  • An estimated 20% of infertile couples experience unexplained infertility.
  • It is a diagnosis of exclusion, given after a complete physical, health evaluation and normal testing find nothing abnormal.
  • While the cause of infertility is “unexplained,” conceiving is still possible.
  • A physician will utilize the results of all fertility testing to help form a holistic understanding of the patients and the best treatment strategy, which can include a combination of lifestyle, medication and reproductive techniques.


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What is unexplained infertility?

Unexplained infertility is a diagnosis reached by process of elimination and given to infertile couples or individuals when infertility testing and examination show no clear reason for inability to conceive.

It is estimated that 20% or more of infertile couples are diagnosed with unexplained infertility. An individual or both partners may receive this diagnosis.

Pregnancy is the result of a complex process involving perfect timing between when a woman releases an egg (ovulation), intercourse, when a man’s sperm fertilizes the egg, and if that fertilized egg successfully implants inside a woman’s uterus. Infertility can happen if there are issues with any of these steps along the way, and unexplained infertility refers to when that issue cannot be identified.

This diagnosis may come as a shock to some patients initially, as it can be very difficult to know one is infertile and not even know why. But it doesn’t mean that there’s no explanation at all or that conception is not possible. It only means that fertility specialists cannot determine an underlying cause after normal testing, that additional factors may be at play, and that further testing and evaluation may be needed.

As with some conditions causing infertility, unexplained infertility may correct itself over time. About 2% of couples with this diagnosis achieve pregnancy without treatment. However, conception is more likely to occur with treatments by fertility specialists.

Diagnosing unexplained infertility

There is no fertility test or combination of tests that can accurately identify all abnormalities that can cause infertility or unexplained infertility. While the complete evaluation of an infertile couple varies, we consider a number of steps to be standard, involving both partners. Steps to diagnosis typically include:

  • Physical exam to assess body mass index, blood pressure, physical indicators and overall health.
  • Review of medical history to understand any menstrual irregularities, prior conditions and other infertility-related issues including lifestyle considerations such as smoking and obesity.
  • Fertility testing including genetic testing, semen analysis, ovarian reserve, hysterosalpingogram (HSG) testing to evaluate the fallopian tubes and ovulation testing. These rule out common fertility problems.
  • Pelvic exam, which may include an ultrasound (sonogram) and HSG imaging to look for abnormalities in the structure or shape of the reproductive organs. Imaging can also identify fibroids or masses in the pelvis or ovaries that can affect fertility.

All the above tests will have either a normal or abnormal result. If the test result is abnormal, such as having low sperm mobility, then the cause of infertility is male factor. However, if all tests are normal, this results in an unexplained infertility diagnosis.

Learn about female and male fertility testing

Unexplained infertility treatment

Even though the individual’s or couple’s infertility is unexplained, treatment to help with conception often follows a course to optimize fertility, from least to more invasive. For example, we may recommend that some patients try lifestyle changes before committing to solutions such as intrauterine insemination (IUI) or in vitro fertilization (IVF).

Treatments commonly used for this diagnosis are listed below, and generally fall under three areas: lifestyle changes, medications and assisted reproductive technologies (ART).

Lifestyle changes

Many lifestyle factors can influence a man’s or woman’s ability to conceive. When the cause of infertility is unexplained, a provider may recommend changes to aid reproduction:

  • Avoid excessive alcohol consumption.
  • Reduce caffeine intake.
  • Lose weight (if overweight) or maintain healthy weight.
  • Exercise regularly.
  • Quit smoking.
  • Reduce overall stress.

Fertility drugs and medications

Fertility drugs regulate or stimulate ovulation. The most common fertility drugs used in treatment are Clomid or gonadotropins, which are used alone or in conjunction with other fertility treatments. Clomid is often tried in conjunction with IUI, which is a form of artificial insemination that places semen into the uterus so the sperm has a better chance of reaching the ovulated egg in the fallopian tube for fertilization.

Fertility drugs are primarily used in unexplained infertility to help a woman’s ovaries produce extra eggs, therefore increasing the chances of pregnancy.

Assisted reproductive technologies

ART encompasses treatments in which eggs or embryos are handled to enhance or assist in fertility. The most common ART is IVF, which involves fertilizing a woman’s egg by a man’s sperm in a lab, then transferring the resulting embryo(s) to the woman’s uterus.

The good news is that fertility treatment for unexplained infertility can work as well as treatment for known diagnoses of infertility. Success rates for unexplained infertility increase from around 4% with Clomid alone, to 10% with Clomid and IUI, and to about 50% with IVF.