Repeated Transplantation Failed 3 Times? ERA Test Accurately Targets Your Specific “Implantation Window” to Improve IVF Success Rate

Why is “Implantation Window” the key to IVF success?

The Golden 48 Hours for Embryo Implantation
In IVF treatment, embryos need to complete the complex process of localization, adhesion, invasion and implantation in the uterus. The success or failure of this series of maneuvers depends on a critical period known as the ‘implantation window’ – the uterine lining is at optimal tolerance for only 24-48 hours per year.

Studies have shown that 30% of repeated transfer failures are directly related to missing the implantation window. Even when transferring chromosomally normal, high-quality embryos, the success rate can plummet to less than 18% if not done at the precise point in time. For women over 38 years of age, the incidence of implantation window deviation is as high as 40%, which is an important reason for the low success rate in older patients.

What is ERA testing?

Genetic Technology Cracks the Endometrial Code
The ERA test (Endometrial Receptivity Analysis) uses second generation sequencing technology (NGS) to accurately determine when the implantation window opens by analyzing the expression patterns of 248 key genes in the endometrial tissue. This technology can detect abnormalities at the molecular level that are not recognized by traditional ultrasound and hormone tests, increasing the accuracy of implantation window determination to 92%.

Core Principles

Gene expression profiling: detects biomarkers related to endothelial tolerance (e.g. HOXA10, IGFBP1).
Artificial Intelligence Algorithm: Compare the global database of 200,000 cases to locate individualized window period
Dynamic monitoring capability: identify window period shortening (<12 hours) due to luteal insufficiency

Explanation of the whole process of ERA testing
Pre-test cycle preparation
Two endometrial preparation programs

Natural cycle (for regular menstruators)
Monitoring of LH peak (luteinizing hormone surge) by urine or blood
Endometrial sampling on LH+7 days
Required in conjunction with 3 consecutive days of ovulation test monitoring and ultrasonography
Artificial cycles (for those with ovulation disorders)
Oral estrogen (4-6mg/day) for 10-14 days
Sampling on day 5 (P+5) after addition of progesterone (progesterone)
Need to take medication strictly on time, missed dose needs to be replaced within 12 hours

Details of endometrial sampling
Painless sampling technique
Gentle aspiration of endometrial tissue using a Pipelle catheter (only 2mm in diameter).
Ultrasound guidance to avoid damage to the basal layer
Takes about 5 minutes, mild abdominal pain lasts for 1-2 hours after the procedure.
Postoperative precautions
Avoid strenuous exercise and heavy lifting for 24 hours.
Prohibit sexual intercourse and pelvic bath for 3 days
Bleeding more than the amount of menstruation need to consult a doctor immediately.

Who needs ERA testing?

List of people who must be tested
Repeated transfer failures: ≥3 high-quality embryos that have not fertilized
Special medical history:
Endometriosis (stage III/IV)
Chronic endometritis (≥5 CD138 positive cells/HPF)
Recurrent biochemical pregnancy (≥2)
Elderly patients: ≥38 years old and AMH <1.1ng/ml
Title H3: Economic benefit analysis of the test
Although ERA testing costs $8,000-15,000 (due to regional variations), it can significantly reduce the cost of comprehensive treatment:

Reduction of embryo waste (average saving of 2 quality blastocysts per cycle)
Reduced pregnancy waiting time (1-2 cycles less with improved success rates)
Reduced risk of miscarriage (from 35% to 12%)

Key factors affecting the accuracy of ERA testing
Three major sources of interference and strategies to deal with them
Poor medication adherence
Missed estrogen doses can lead to delayed endothelial development
Solution: set cell phone medication reminders, use split pill boxes
Sampling timing deviation
Natural cycles do not accurately capture peak LH (requires combined serum testing)
Progesterone dosing time error >2 hours in manual cycle
Solution: Choose a fertility center to centrally manage cycles
Potential uterine pathology
Endometrial polyps >5mm can distort gene expression results
Solution: hysteroscopy + pathologic biopsy first

How to interpret the ERA test report?
Three types of results in the report
Receptive
Shows specific time point of implantation (e.g. 124±2 hours after progesterone administration)
need to be transplanted strictly at this time in the next cycle
Pre-Receptive
Indicates the need for prolonged luteal support (e.g., increase progesterone by 1-2 days)
Post-Receptive
Need to transfer 24-48 hours earlier, or adjust estrogen dosage
Heading H3: Special case management
Very short window period (<12 hours): recommend embryo synchronized hatching technique (AH)
Split window (two tolerance periods): optimal timing needs to be chosen in conjunction with the rate of embryo development

Clinical data validation of the ERA test
Results of an international multicenter study
According to the paper published in Fertility and Sterility 2023:

In a population of repeat implantation failures, the ERA test increased clinical pregnancy rates from 26% to 51%
37% increase in live birth rate and 58% reduction in miscarriage rate
Typical Cases

Case 1: 39 year old woman with 4 previous failed transplants, ERA test revealed a 32 hour delay in the window compared to normal, adjusted to a successful pregnancy.
Case 2: thin endometrium (always <6mm), ERA test guided individualized estrogen medication regimen, endometrial thickness increased to 8mm

Future direction of technology development
Breakthroughs of the third-generation ERA test
Multiple time-point sampling: 3 samples are collected at different times during the cycle, and the dynamic curve of window period is plotted
Combined immunoassay: simultaneous detection of NK cell activity and Th1/Th2 cytokine balance
Home test kit: development of self-testable endometrial tolerance test strips (expected to be available in 2025)

Frequently Asked Questions
Clarification of concerns about the test
Q: Can sampling damage the endometrium?
A: Modern sampling catheters only aspirate the functional layer of endometrium (approximately 0.1mm thick), and studies have confirmed that it does not affect subsequent implantation.

Q: Can the test results be used for a long time?
A: It is recommended to use them within 1 year, and re-testing is required for more than 2 years (endothelial status changes with age).

Expert Advice and Action Guidelines

Allow at least 2 menstrual cycles to complete the test and analyze the results before implantation.
Choose a PGT-A (embryo chromosome screening) qualified institution for combination therapy
Improve endometrial blood flow with uterine perfusion (e.g., HCG or granulocyte colony-stimulating factor)
Individualized “implantation window” is targeted through ERA testing to restore hope to patients with repeated implantation failures. Remember, every precise timing is the beginning of the miracle of life!