Unexplained Infertility Causes: Why You Are Not Getting Pregnant and What to Do

10 Apr Unexplained Infertility Causes: Why You Are Not Getting Pregnant and What to Do

Unexplained infertility causes more emotional confusion than almost any other fertility diagnosis precisely because there is no visible problem to fix. Being told that all your tests are normal, yet you still cannot conceive, can feel more bewildering than receiving a difficult diagnosis. At least a diagnosis gives you something to act on.

The reality is that unexplained infertility causes a significant proportion of fertility cases worldwide accounting for approximately 10–30% of all infertility diagnoses. It does not mean nothing is wrong. It means that standard investigations have not yet identified the reason. And with today’s advanced diagnostics and fertility treatments, there are clear, meaningful next steps for every couple in this position.

At Fertibless Clinic in Delhi, Dr. Shipra Gupta takes a thorough, layered approach to investigating unexplained infertility causes going beyond standard tests to find answers that other workups may have missed.

What Is Unexplained Infertility?

Unexplained infertility is diagnosed when a couple has been unable to conceive after 12 months of regular unprotected intercourse or 6 months for women over 35 and all standard investigations return normal results. These investigations typically include semen analysis, ovulation confirmation, fallopian tube assessment, and baseline hormonal testing.

Even when results are normal, unexplained infertility causes very real challenges for conception. The term reflects the limits of current standard testing not the absence of a biological reason. In many couples, advanced investigations do uncover a contributing factor that routine tests simply cannot detect.

Why Standard Tests Miss Key Unexplained Infertility Causes

Standard fertility investigations are thorough but not exhaustive. Several biologically meaningful factors known to interfere with conception are simply not detected by routine blood tests or ultrasound:

• Egg Quality: Subtle egg quality issues AMH and FSH measure quantity, not chromosomal quality. Minor abnormalities in eggs are only detectable through genetic embryo testing (PGT-A) during IVF, making chromosomal egg defects one of the most common hidden unexplained infertility causes.
• Sperm DNA: Sperm DNA fragmentation — A basic semen analysis checks count, motility, and morphology but not the integrity of the sperm’s genetic material. High DNA fragmentation can cause fertilisation failure or early embryo loss even when semen parameters appear completely normal.
• Implantation: Implantation failure Uterine receptivity issues including disruptions to the endometrial microbiome, immune cell activity, or the timing of the implantation window — may prevent a healthy embryo from attaching. None of these are detected by standard imaging.
• Endometriosis: Minimal endometriosis — Lesions too small to detect on ultrasound, or pelvic adhesions only visible through direct laparoscopic assessment, can subtly impair egg pickup and fertilisation.
• Luteal Phase: Luteal phase deficiency — Inadequate progesterone production after ovulation may impair the endometrial preparation needed for successful implantation.
• Ovulation Quality: Subtle ovulation dysfunction — Some women ovulate, but follicle rupture timing, follicular fluid composition, or egg maturity may be suboptimal in ways not captured by standard hormonal monitoring.

Identifying these hidden unexplained infertility causes requires more specialist investigation — and is where the Fertibless approach goes further.

Advanced Investigations to Identify Unexplained Infertility Causes

When standard tests come back normal, the following advanced investigations may reveal the underlying unexplained infertility causes in your case:

• Sperm DNA Test: Sperm DNA Fragmentation Index (DFI) — Assesses the genetic integrity within sperm. A DFI above 25–30% is associated with reduced fertilisation, poor embryo development, and recurrent pregnancy loss — even with entirely normal semen analysis.
• Hysteroscopy: Hysteroscopy — Direct visualisation of the uterine cavity to identify subtle polyps, adhesions, fibroids, or surface irregularities not visible on ultrasound.
• Laparoscopy: Laparoscopy — The only definitive way to diagnose and exclude minimal or mild endometriosis and pelvic adhesions, which are among the most frequently missed unexplained infertility causes.
• ERA Test: ERA (Endometrial Receptivity Analysis) — A genomic test that analyses endometrial gene expression to identify whether the implantation window is displaced from the standard timing. Some women’s windows are shifted by 12–24 hours, which makes standard-timed transfers ineffective.
• Immune Testing: Thrombophilia and Immunological Screening — Tests for antiphospholipid antibodies, elevated uterine NK cells, and clotting disorders that may prevent implantation or cause early pregnancy loss.
• Karyotyping: Karyotyping — Chromosomal analysis of both partners to identify balanced translocations or other subtle genetic abnormalities that contribute to failed fertilisation or early embryo arrest.

Treatment Options Based on Identified Unexplained Infertility Causes

Treatment for unexplained infertility is most effective when it is guided by what advanced investigations reveal. When specific unexplained infertility causes are identified, targeted treatment can be applied. When no specific cause is found, empirical treatment strategies offer meaningful improvement in success rates:

Expectant Management with Timed Intercourse

For younger couples (woman under 35) with a short duration of infertility and no additional risk factors, a period of closely monitored natural conception may be advised before proceeding to assisted treatment. Monthly fecundity — the chance of conception per cycle — in unexplained infertility is approximately 1–4%, meaning spontaneous conception is still possible during this period.

Ovulation Induction with IUI

Combining mild ovarian stimulation with intrauterine insemination increases the number of eggs available for fertilisation and optimises sperm placement at the right time. This approach typically offers success rates of 8–15% per cycle and is a reasonable first step for couples where unexplained infertility causes have not pointed to a more specific intervention.

IVF

IVF is the most effective treatment for unexplained infertility. By bringing egg and sperm together in a controlled laboratory environment, the embryologist can directly observe fertilisation, embryo development, and quality. Critically, IVF also provides diagnostic information if fertilisation fails or embryos consistently arrest early, this reveals biological evidence about underlying unexplained infertility causes that no blood test could show.

IVF with PGT-A

For couples with repeated implantation failures, PGT-A screens embryos for chromosomal abnormalities before transfer. Transferring only chromosomally normal (euploid) embryos substantially reduces the risk of failed implantation and miscarriage — regardless of the woman’s age. This is particularly valuable when egg chromosomal issues are suspected as contributing unexplained infertility causes.

Expert Insight — Dr. Shipra Gupta When unexplained infertility causes frustration and confusion for a couple, my first commitment is to investigate more deeply — not to offer generic reassurance. We expand our investigations: sperm DNA fragmentation, hysteroscopy, sometimes laparoscopy, the ERA test, immune screening. Very often, a more thorough look reveals something that standard tests missed. And even when it does not, IVF gives us a controlled environment where we can observe the fertilisation and embryo development process directly — which itself tells us a great deal about what underlying unexplained infertility causes may be at play. No couple should walk away with just ‘keep trying.’ — Dr. Shipra Gupta, Infertility Specialist, Fertibless Clinic, Delhi

The Emotional Reality of an Unexplained Diagnosis

Among all unexplained infertility causes of distress during a fertility journey, receiving no diagnosis at all is often the hardest to bear. Couples frequently experience:

• Self-blame and guilt — Wondering whether something they did or did not do caused the problem.
• Frustration with the medical process — Feeling that investigations have not gone far enough.
• Fear of hoping — Particularly in couples who have experienced previous pregnancy loss alongside unexplained infertility.
• Social isolation — Difficulty discussing a diagnosis that has no simple explanation with friends or family.

At Fertibless, we believe emotional support is inseparable from medical care. Counselling, fertility peer communities, and open communication with your care team are all part of the journey — and Dr. Shipra Gupta makes time to address the emotional reality of unexplained infertility alongside its clinical management.

Reference: American Society for Reproductive Medicine (ASRM) — www.asrm.org | WHO Reproductive Health Library — www.who.int | NIH PubMed — www.ncbi.nlm.nih.gov/pubmed

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