After two or three consecutive failed embryo transfers, many families reach the most devastating stage of their IVF journey.

The psychological blow is even greater when doctors tell them, “The embryo quality is good.”

Instinctively, many begin to wonder:

Is there something wrong with my uterus?

Is my immune system rejecting the embryo?

Do I need more advanced testing?

However, reproductive medicine statistics reveal that in cases of recurrent implantation failure, the most common cause remains chromosomal abnormalities in the embryo—not uterine issues.

This finding often contradicts public intuition.

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I. What is “Implantation Failure”?

First, let's clarify a concept.

Medicine lacks a universally agreed-upon number defining “recurrent implantation failure,” but clinically it typically refers to:

At least 2-3 transfers of high-quality embryos

No biochemical or clinical pregnancy occurring

Note a crucial point:

“High-quality embryos” refers to morphologically high-quality embryos, not chromosomally high-quality ones.

These two concepts are fundamentally different.

II. The True Mechanism of Embryo Implantation

Many assume implantation is simply “the embryo enters and sticks.”

In reality, it is an extremely complex molecular-level process.

Implantation requires three conditions:

The embryo must possess the capacity for continued development

The endometrium must be in the implantation window phase

The maternal immune system must permit the embryo's presence

Failure in any one of these steps can lead to failure.

But the key point is:

Step one—whether the embryo itself is normal—is the decisive factor.

III. Why Are Embryo Issues More Common?

Let's examine the clinical data logic.

Among women under 35:

Embryo chromosomal abnormality rate: approximately 30%

Among women over 38:

Embryo chromosomal abnormality rate: can reach 50%-70%

This implies:

Even if you transfer an “AA-grade blastocyst,”

it still carries a significant probability of chromosomal abnormalities.

Good morphology ≠ genetic normality.

Chromosomal abnormalities in embryos:

May prevent implantation altogether

Or cause early development arrest after implantation

Therefore, when facing recurrent implantation failure, the first question to ask is:

Have we confirmed the embryo's chromosomal integrity?

IV. Are uterine issues truly that common?

Many individuals immediately undergo various uterine cavity examinations after a failure.

However, statistically speaking:

The proportion of implantation failures caused by severe uterine structural abnormalities is not high.

Common uterine factors include:

Endometritis

Uterine adhesions

Significant uterine malformations

Uterine fibroids affecting the cavity

These issues are typically detected through:

Hysteroscopy

Ultrasound

Endometrial biopsy

If all tests are normal,

the likelihood of uterine factors significantly decreases.

V. Are Immune Issues Overemphasized?

In recent years, “immune infertility” has become a buzzword.

However, from an evidence-based medicine perspective:

The proportion of implantation failures definitively caused by immune abnormalities is not high.

Some so-called “immunological tests” lack standardized diagnostic criteria.

Overuse of:

Immunosuppressants

High-dose hormones

Immunoglobulins

may increase physical burden and financial strain.

This does not negate the existence of immune factors,

but emphasizes:

Decisions must be grounded in solid evidence, not fear-driven assumptions.

VI. How to Establish a Scientific Evaluation Sequence?

When facing recurrent implantation failure, the rational pathway should be:

Step 1: Confirm embryo quality

Has chromosomal screening been performed?

Step 2: Evaluate uterine cavity structure

Is there chronic inflammation or adhesions?

Step 3: Assess endometrial receptivity

Is there endometrial thinning or cycle desynchronization?

Step 4: Only consider immune factors after ruling out the above issues.

Wrong sequence leads to misdirection.

VII. Real-Case Logic

Case 1:

37-year-old woman with three consecutive failed transfers.

All embryos were morphologically high-quality blastocysts.

No chromosomal screening performed.

Fourth cycle revealed after embryo screening:

Only 1 of 5 embryos had normal chromosomes.

Successful pregnancy after transfer.

The core issue was the embryo, not the uterus.

Case 2:

32-year-old woman with two failed transfers of chromosomally normal embryos.

Hysteroscopy revealed chronic endometritis.

Successful pregnancy achieved after three months of treatment.

This is a classic uterine factor.

The key lies not in “which factor is more common,”

but in systematically investigating causes step by step.

VIII. Psychological Impact

Repeated failures may trigger:

Self-blame

Doubt about one's body

Couple stress

However, statistically speaking:

Consecutive failures do not equate to permanent failure.

Over multiple cycles, most couples ultimately achieve pregnancy.

Psychological stability supports:

Hormonal balance

Endometrial environment

Cycle compliance

IX. Misconceptions Requiring Vigilance

Misconception 1:

Aggressively escalating immune therapy after a single failure

Misconception 2:

Repeated surgical interventions on the uterus

Misconception 3:

Neglecting male sperm DNA issues

Misconception 4:

Blindly switching treatment protocols without systematic evaluation

Medical decisions should be grounded in evidence, not anxiety.

X. Core Conclusions

In recurrent implantation failure:

Embryo chromosomal abnormalities are the most common cause

Uterine factors are the second most common cause

Immune factors account for a relatively low proportion

The correct approach is:

Step-by-step investigation

Precision intervention

Rather than emotionally driven decisions

What truly improves success rates is not increasing the number of tests,

but enhancing the quality of decision-making.

For fertility consultation in Kyrgyzstan, please contact your dedicated consultant

/Fertility Consultation /

Dr.Chan

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