Dr. Ghina ShamiReproductive Medicine and Infertility · Dubai
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Conditions

Unexplained infertility

“Unexplained” is a diagnosis many couples find harder to accept than a clear problem. It means that the standard tests have not found a cause, not that there is nothing to understand or do. Guidelines describe a complete basic assessment first, then options chosen according to age and how long you have been trying.

What it means

Infertility is called unexplained when a couple has been trying for at least a year and the standard tests are normal: the woman ovulates, the fallopian tubes are open, the uterus looks normal and the semen analysis is normal. It is common: the NHS estimates that no cause can be found for about a quarter of couples with fertility problems, and ESHRE estimates about 30%. The cause may lie in steps that routine tests cannot see, such as how the eggs and sperm work, fertilisation or implantation.

What a complete assessment covers

The diagnosis rests on how complete the tests are. A standard assessment includes a history and examination for both partners; checking that ovulation happens (regular monthly cycles usually mean ovulation, and some guidelines, such as NICE, advise a progesterone blood test in the second half of the cycle to confirm it); a test that the tubes are open, such as a hysterosalpingogram (HSG) or a contrast ultrasound (HyCoSy); and at least one semen analysis read against WHO reference values, repeated if abnormal. NICE also suggests considering a blood test for coeliac disease.

Endometriosis can be present without obvious symptoms. The guidelines do not recommend routine laparoscopy to look for it, but your doctor may consider one if your history suggests endometriosis. See endometriosis.

Age and time

Age and how long you have been trying are the two facts that most change the outlook. Female fertility declines with age, and male fertility does so to a lesser extent. NICE notes that, among couples in the general population where the woman is under 40, about half of those who have not conceived after a year of trying do so in the following year. Prediction models can help with decisions, though none is fully reliable, so the plan rests on your own age, history and preferences.

Options guidelines describe

  • Continuing to try. For couples with a good outlook, continuing to try naturally is reasonable; NICE advises trying for a total of two years before treatment.
  • IUI with ovarian stimulation. ESHRE recommends it as first-line treatment for unexplained infertility; NICE suggests considering up to four cycles before IVF. Stimulation raises the chance of twins, so cycles are monitored. See IUI.
  • IVF. An option after IUI or instead of it, depending on age, how long you have been trying and previous treatment. See IVF and ICSI.
  • Not recommended. Most add-ons and supplements have not been shown to help in unexplained infertility.

The guidelines differ in detail, and many of their recommendations rest on low-quality evidence; your doctor can explain how they apply to you.

Questions worth asking your doctor

  1. 1

    Which tests have we had, and is anything missing?

    Ovulation, the fallopian tubes, the uterus and a semen analysis should all have been checked.

  2. 2

    What do our ages and time trying mean for the outlook?

    These two factors change the outlook most and help decide when treatment makes sense.

  3. 3

    What are the benefits and risks of IUI and IVF for us?

    Including the chance of twins and how many cycles are planned.

Dr. Ghina Shami

Common questions

Does unexplained mean there is no problem?

It means only that the standard tests have not found one. Problems in steps that routine tests cannot see, such as fertilisation or implantation, may be involved.

Should we go straight to IVF?

Not necessarily. ESHRE recommends IUI with ovarian stimulation as first-line treatment, and NICE advises trying naturally for two years in total before treatment, then considering IUI or IVF. Age, time trying and previous treatment affect the choice.

Could stress be the cause?

Infertility often causes stress, and stress can lower sex drive and how often couples have sex. A review of 14 studies published in the BMJ in 2011 found that emotional distress did not lower the chance of pregnancy with fertility treatment. Counselling and psychological support are recommended when needed.

Evidence basis: This page is based on the 2023 ESHRE guideline on unexplained infertility and the 2026 NICE fertility guideline; both state that much of the evidence in this area is of low quality, and the page notes where they differ. These sources rest on studies and, where studies are lacking, on expert consensus.

References

  1. Evidence-based guideline: unexplained infertility. ESHRE, Human Reproduction. 2023. doi:10.1093/humrep/dead150.
  2. Fertility problems: assessment and treatment (NICE guideline NG257). NICE. 2026. Available from: nice.org.uk/guidance/ng257.
  3. Infertility. NHS. 2023. Available from: nhs.uk/conditions/infertility.
  4. Emotional distress in infertile women and failure of assisted reproductive technologies: meta-analysis of prospective psychosocial studies. BMJ (Boivin et al.). 2011. Available from: pmc.ncbi.nlm.nih.gov/articles/PMC3043530.

Written and reviewed by Dr. Ghina Shami, Consultant, Reproductive Medicine and Infertility · · How these pages are prepared