Unexplained Infertility

Unexplained infertility is when fertility testing hasn't found a cause to explain a person or couples infertility. Treatments include fertility medication, lifestyle changes, intrauterine insemination (IUI) and in vitro fertilization (IVF).


What is unexplained infertility?

Unexplained infertility is a term healthcare providers use to describe infertility after tests reveal no obvious cause for your fertility problems. Providers only diagnose unexplained infertility after both partners have had complete fertility evaluations. Often, these tests reveal:

  • No uterine abnormalities or structural issues with your uterus.
  • Ovulation occurs at regular intervals.
  • Your fallopian tubes are open, with no obstructions.
  • Your egg count is good (ovarian reserve).
  • Your brain produces normal levels of the hormones needed for reproduction.
  • Your partner’s semen analysis is normal (count, amount, motility and shape).

People diagnosed with unexplained infertility have been trying to get pregnant for at least one year (if you're younger than 35) or six months (if you're 35 or older).

Fertility treatments and assisted reproductive technologies (ART) like IUI (intrauterine insemination) and IVF (in vitro fertilization) can help couples get pregnant.


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How many couples have unexplained infertility?

The exact rates vary because the definition of fertility testing varies. What one provider considers standard or comprehensive fertility testing may differ from other providers.

According to one source, in 10% of couples trying to conceive, fertility tests are normal and there’s no detectable cause for infertility. But another source says unexplained infertility cases are as high as 30%.

Is it possible to get pregnant with unexplained infertility?

Yes, it's possible to get pregnant if you're diagnosed with unexplained infertility. A study from the National Institute of Health (NIH) found that 92% of couples with unexplained infertility who had fertility treatments ultimately had a child. A diagnosis of unexplained infertility doesn't mean you have to give up your dreams of a baby.


Symptoms and Causes

What are the causes of unexplained infertility?

Unexplained infertility has no cause, or if a cause exists, providers can’t measure it or test for it. Some possible reasons for unexplained infertility are:

  • An undiagnosed underlying condition: No one is completely sure how every condition affects fertility. Researchers are always studying to learn more about how our bodies work. For example, celiac disease (a gluten allergy), diabetes and thyroid conditions contribute to infertility.
  • Endometriosis: Even mild cases of endometriosis could contribute to infertility. Your healthcare provider diagnoses endometriosis in surgery. Even mild endometriosis or endometriosis with no symptoms could contribute to infertility.
  • Cervical mucus: Your cervical mucus helps sperm swim up to meet your egg during ovulation. If your cervical mucus is thick or contains certain ingredients, sperm may not be able to travel through your cervix and vagina to get to your uterus.
  • Egg quality: Healthcare providers can measure how many eggs you have through an ultrasound (by looking at follicles in your ovary), but ultrasound doesn’t tell them about egg quality. Blood tests and ultrasound can give clues about the quality of your eggs, but it’s not a definitive diagnosis.
  • Sperm quality: Similar to egg quality, a sperm analysis reveals most problems with sperm. But there may be other issues with sperm that contribute to unexplained infertility.
  • Uterine lining: Your endometrium is the lining of your uterus. It’s what an embryo sticks to and grows in during pregnancy. A luteal phase defect is when your endometrium doesn't thicken or prepare itself for a fertilized egg. This means if an egg gets fertilized, it can’t implant, which means you won’t get pregnant.
  • Poorly timed intercourse: The frequency or timing of sex isn’t matching up with ovulation.

Sometimes there is no cause or the cause is hard to diagnose or treat. A lot needs to happen to achieve a pregnancy, and many things can disrupt the process. Luckily, researchers are always finding new ways to identify fertility issues related to egg quality, reproductive organ function and sperm function.

Diagnosis and Tests

How is unexplained infertility diagnosed?

There isn’t one fertility test that can diagnose all irregularities that cause infertility. And testing methods aren’t 100% accurate (for example, they may not detect mild abnormalities). The American Society of Reproductive Medicine (ASRM) says fertility testing should include:

  • A complete medical and sexual history.
  • A physical exam.
  • Blood tests to look at hormone levels.
  • Assessment of reproductive organs such as your ovaries, fallopian tubes and uterus. This may include ultrasound or more advanced imaging tests like a hysterosalpingogram or laparoscopy.
  • Semen analysis.
  • Ovarian reserve testing.
  • Checking your ovulation.

If a fertility specialist or obstetrician performs comprehensive testing and still can't find a cause, they may diagnose unexplained infertility. Remember, every provider may have a different protocol for fertility testing. It's OK to get a second opinion if you receive an unexplained infertility diagnosis.


Management and Treatment

What are treatments for unexplained infertility?

Because your healthcare provider can’t identify one cause for infertility, they will most likely recommend treatment based on your fertility test results and their experience with similar couples or individuals. Other factors include how aggressive you want to be with treatment and your age.

The most common treatments fall under the following categories:

Assisted Reproductive Technology (ART)

ART is a type of fertility treatment that usually involves part of the fertilization process happening in a lab. ART treatment includes intrauterine insemination (IUI) and in vitro fertilization (IVF). IUI is when providers wash and concentrate sperm in a lab before injecting it into your uterus at ovulation. IVF involves creating embryos in a lab using your eggs and your partner’s (or donor) sperm, then moving the embryo to your uterus to grow. IVF often involves intracytoplasmic sperm injection (ICSI), a procedure where providers inject sperm directly into your egg. ICSI increases your chance of pregnancy when sperm quality may be the cause of unexplained infertility.


Medications that stimulate egg production and ovulation are helpful and you can use them alone or with IUI and IVF treatment. The most common medications are gonadotropins and clomiphene (Clomid®). Some providers prescribe letrozole (Femara®) for fertility, but it’s an off-label use.

Gonadotropins contain hormones that promote egg production and treat low sperm count. Clomiphene also works by stimulating the ovaries to produce more eggs. Your healthcare provider will recommend an approach based on your situation.

Keep in mind that you may produce more than one egg per cycle using fertility medication, which increases your chances of having more than one baby.

Lifestyle changes

Several lifestyle factors contribute to infertility. Some things you can do to help your chances of conceiving are:

  • Avoid smoking, drinking alcohol and using recreational drugs.
  • Maintain a healthy weight.
  • Eat a well-balanced diet.
  • Try to get 30 minutes of exercise each day.
  • Limit caffeine consumption.
  • Reduce your stress.

Improved timing of intercourse

There is a small window of time in your menstrual cycle that conception can occur. Your healthcare provider may help you identify this window to maximize your chances of getting pregnant. This could involve taking your temperature, charting your cycle or using ovulation kits to predict ovulation.

Some healthcare providers recommend trying longer. This may be a hard treatment plan to understand, especially when you have dreams of starting a family as soon as possible. Sometimes the problem resolves on its own, and treatment isn't needed. It’s OK to get a second opinion or want to be more aggressive with fertility treatment.


Is there a way to prevent unexplained infertility?

While you can do things to increase your chances of conception, some infertility factors are out of your control. Some of the factors within your control are:

  • Weight: Maintain a weight that’s healthy for you.
  • Smoking tobacco and drinking alcohol: Avoid smoking cigarettes and drinking too much alcohol.
  • Sexual history: Reduce your risk for sexually transmitted infections (STIs) by wearing condoms.

Talk with your healthcare provider about your fertility concerns so they can recommend the next steps for your care.

Outlook / Prognosis

How many couples with unexplained infertility get pregnant?

One study found that up to 43% of people eventually got pregnant without fertility treatment.

Living With

What questions should I ask my healthcare provider if I have unexplained infertility?

It's normal to have many questions about a diagnosis of unexplained infertility. The good news is no major problems are causing your infertility. The bad news is your provider can’t determine why you’re not getting pregnant.

Discuss your concerns with your healthcare provider and ask them things like:

  • What would you recommend I do next?
  • What gives me the best chance for pregnancy?
  • Are there any blood or imaging tests left to perform?
  • Could an underlying condition cause my infertility?
  • Should I see a fertility specialist?

Additional Common Questions

How long should I try to get pregnant before contacting my doctor?

Most healthcare providers recommend waiting at least 12 months (or one year) before seeking infertility treatment. However, if you're 35 or older, you should contact your provider after six months. Your provider can suggest treatments based on your health history and desire for pregnancy.

A note from Cleveland Clinic

Unexplained infertility can be a frustrating and confusing diagnosis. It means that no one can determine why you’ve been unable to conceive. Try not to feel discouraged — there are treatments to help you. Some couples and individuals find success through medication, IUI or IVF. Unexplained infertility doesn't mean you won't ever have a baby. It means your healthcare providers may need to explore different options to achieve a pregnancy. Find a provider who understands your emotions and supports you through this challenging time.

Medically Reviewed

Last reviewed on 06/07/2022.

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