Unexplained Infertility: Causes, Diagnosis, and Treatment Options

In short: Unexplained infertility means no pregnancy after 12 months of trying (or 6 months for women over 35) although the couple’s tests are normal; it accounts for 10–20% of cases. It may be due to a hidden problem in egg quality, sperm function or implantation. Treatment goes step by step, from watchful waiting in women under 35, to ovulation stimulation with insemination, then ICSI.

Unexplained infertility is diagnosed when a couple has not achieved pregnancy after 12 months of regular, unprotected intercourse, or after 6 months if the woman is over 35 years of age. Despite significant advancements in diagnostic methods, approximately 10-20% of cases remain classified as unexplained infertility, where routine tests for both partners appear normal.

This diagnosis can feel especially frustrating, both clinically and emotionally, because there is no clear underlying cause toward which treatment can be directed. Many patients find comfort in knowing that this is a recognized medical category with established management options, not a sign that something has been overlooked.

Diagnostic Assessment:

Unexplained infertility is diagnosed after completing basic investigations, which include:

1- Evaluation of ovulation through ultrasound monitoring of follicles.

2- Semen analysis according to World Health Organization standards.

3- Assessment of the patency of the fallopian tubes.

4- Evaluation of the uterine cavity by ultrasound or hysteroscopy, if needed.

When these elements are normal, the diagnosis is made by exclusion — meaning all common causes have been checked and ruled out.

Possible Pathological Mechanisms:

Despite the absence of a clear defect, studies point to several subtle mechanisms that may explain the condition, including:

• Subtle disturbances in egg quality.
• Subtle sperm dysfunction (DNA fragmentation).
• Disruptions in the interaction between egg and sperm.
• Problems with embryo implantation in the uterine lining.
• Subtle immunological abnormalities.

Some recent research published in journals suggests that a percentage of these cases may be reclassified later with the development of genetic and functional testing techniques.

Treatment Plan:

Management depends on the woman’s age and how long the couple has been trying to conceive:

1- Expectant Management.

Suitable for women under 35 years of age with a short period of delayed pregnancy, allowing more time for natural conception.

2- Ovulation Induction with Intrauterine Insemination (IUI).

This is the first-line option in most cases, especially within 3-6 treatment cycles.

3- In Vitro Fertilization (IVF/ICSI).

IVF is recommended when IUI has failed, when the wife is older (around 38 or above), or when infertility has lasted a long time (more than 3 years). Conventional IVF is usually suitable, and ICSI is used when there is a sperm problem or fertilization failed in a previous cycle, as it has not been shown to give better results than IVF in unexplained infertility.

Data shows that pregnancy rates in this group are often encouraging when IVF is used, suggesting a minor, otherwise undetectable dysfunction that can be overcome through laboratory-based fertilization techniques.

Psychological aspects:

Studies indicate that women with unexplained infertility often experience higher levels of anxiety compared to those with a clear organic cause, due to the lack of a direct explanation. Emotional support and open communication with your care team are an important part of the overall treatment plan, alongside the medical steps above.

If you and your partner have been facing unexplained infertility, Dr. Najeeb Layyous and his team can guide you through a structured diagnostic and treatment plan tailored to your situation. Contact the clinic to discuss your case and explore the most suitable next steps.

Dr Najeeb Layyous F.R.C.O.G

Consultant Obstetrician, Gynecologist and Infertility Specialist