What are the causes of IVF failure in Hong Kong? | Embryo chromosomes · Ovarian reserve · Uterine cavity environment

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1. Direct Answer: Objective Medical Reasons for IVF Failure in Hong Kong

From a reproductive medicine perspective, IVF failure is not caused by a single factor. In Hong Kong assisted reproduction centers, over 60% of failure cases are directly related to embryonic factors, followed by uterine environment and immune factors. The seven most common clinical categories are listed below:

• Embryo chromosomal abnormalities — Aneuploidy is the primary cause of implantation failure or early miscarriage, especially in women of advanced maternal age (≥35 years), with an incidence rate of 50%-70%.
• Diminished ovarian reserve — AMH ≤ 1.0 ng/mL, antral follicle count (AFC) < 6, leading to low oocyte yield and poor embryo quality.
• Uterine cavity factors — Endometrial polyps, intrauterine adhesions, thin endometrium (≤6 mm), and chronic endometritis (CD138 positive) prevent embryo implantation.
• Sperm quality defects — When DNA fragmentation index (DFI) > 30%, even with normal morphology and motility, embryos are prone to developmental arrest in early stages.
• Mismatched ovarian stimulation protocol — Abnormal ovarian response (low or high response) leads to suboptimal oocyte retrieval outcomes.
• Laboratory culture environment issues — Differences in culture media, pH, oxygen concentration, and embryo grading standards can affect embryo developmental potential.
• Maternal immune and coagulation abnormalities — Antiphospholipid antibodies, elevated NK cell activity, and prothrombotic states interfere with the implantation process.

2. Why Does Failure Occur? — Key Pathological Mechanisms at Each Stage

2.1 Embryonic Factors: Chromosomal Aneuploidy is the "Number One Killer"

Errors in oocyte meiosis increase significantly with age. The aneuploidy rate in embryos is about 30% for those under 35, exceeds 60% after age 40, and can reach 90% after age 45. Some centers in Hong Kong routinely recommend PGT-A (Preimplantation Genetic Testing for Aneuploidy) for women of advanced maternal age or those with recurrent implantation failure. However, it is important to note that PGT-A itself does not improve the quality of each egg; it only aids in selection.

2.2 Insufficient Ovarian Reserve: Dual Constraints on Oocyte Quantity and Quality

AMH reflects ovarian reserve but is not the sole indicator. Some patients have normal AMH (>1.5 ng/mL) but a high rate of follicular atresia, resulting in fewer oocytes retrieved than expected. Additionally, heterogeneous follicle development and empty follicle syndrome can also lead to failure.

2.3 Abnormal Uterine Cavity Environment: The Overlooked "Soil Problem"

Hong Kong reproductive centers place a high emphasis on hysteroscopy. Local data indicates that about 35% of patients with recurrent failure have uterine cavity lesions undetected by ultrasound, with polyps (20%) and chronic endometritis (12%) being the most common. CD138 immunohistochemical staining is the gold standard for diagnosing endometritis.

3. How Do Doctors View the Causes of Failure? — Clinical Diagnostic Logic

Reproductive medicine specialists in Hong Kong (e.g., at Union Hospital, Hong Kong Sanatorium & Hospital Fertility Centre) typically follow this sequence when reviewing failure cases:

1. Step 1 → Review embryo chromosomal results (if PGT-A was performed, check the screening report; if not, recommend peripheral blood karyotyping of both partners and CNV analysis of any remaining embryonic tissue).
2. Step 2 → Perform saline infusion sonography or hysteroscopy to rule out anatomical factors.
3. Step 3 → Sperm DFI test (normal < 15%, borderline 15-30%, abnormal > 30%).
4. Step 4 → Maternal immune panel: blocking antibodies, antiphospholipid antibodies, NK cell activity, homocysteine, etc.
5. Step 5 → Review the ovarian stimulation cycle: check for abnormalities in LH levels, estradiol peak, progesterone elevation, etc.

Doctors pay special attention to details such as "whether the stimulation protocol was changed" and "whether assisted hatching or blastocyst transfer was attempted previously."

4. Details Most Easily Overlooked

• Embryo culture time cut-off: Some centers primarily transfer Day 3 cleavage-stage embryos, but some embryos only form good-quality blastocysts on Days 5-6. Failing to culture to the blastocyst stage may mean missing potentially transferable embryos.
• Endometrial microbiome: Some Hong Kong laboratories have started performing endometrial microbiome testing (EMMA/ALICE), finding that a lack of Lactobacillus is associated with implantation failure.
• Vitamin D levels: Serum 25(OH)D < 30 ng/mL is associated with reduced implantation rates. Local Hong Kong studies suggest that about 40% of infertile women have insufficient levels.
• Thyroid autoantibodies: Even with normal TSH, TPO antibody positivity increases the risk of early miscarriage.

5. Common Pitfalls (In the Context of Hong Kong Medical Scenarios)

6. Differences Across Age Groups (Impact on the Weight of Failure Factors)

7. Factors Affecting the Cost of IVF in Hong Kong (Indirect Dimensions Related to Failure)

Failure may lead to additional costs, including but not limited to:

• Repeated transfer cycles: Each transfer cycle costs approximately HKD 30,000-50,000 (excluding medication).
• PGT-A testing: Approximately HKD 5,000-8,000 per embryo tested, accumulating for multiple embryos.
• Hysteroscopic surgery: Approximately HKD 15,000-30,000, with additional costs for polypectomy or endometritis treatment.
• Sperm DFI + complete immune panel: Approximately HKD 3,000-6,000.
• Third-party egg/sperm donation: Legal in Hong Kong but more expensive, with a waiting period of at least 6-12 months.

8. Observations from Practitioners (Ten Years of Experience in Hong Kong Assisted Reproduction Coordination)

In practice, the most common problem observed in failure-related decision-making is: patients' reluctance to undergo tests beyond "non-invasive" ones. Many patients with recurrent failure refuse hysteroscopy, believing that "an ultrasound has already been done," but the sensitivity of ultrasound for mild adhesions and endometritis is less than 30%. Another phenomenon is that some Hong Kong doctors recommend "mild stimulation protocols" for patients with low ovarian reserve, but mild stimulation yields only 1-3 oocytes per cycle, and achieving a cumulative pregnancy rate requires multiple cycles. Many patients cannot persist and give up midway.

Additionally, psychological stress on the couple also affects endocrine and immune function. Although not a direct medical cause, clinical observations show a higher cycle cancellation rate in patients with chronic high anxiety. It is recommended to proactively seek reproductive psychological support after two failures.

Ending random: Doctor's advice

This article is compiled based on publicly available reproductive medicine literature and clinical consensus from some Hong Kong reproductive centers. It is for informational reference only and does not constitute medical advice. For specific diagnosis and treatment, please consult a legally registered reproductive medicine physician.