Treatment Overview
An Endometrial Receptivity Test (often called ERA or a gene-expression receptivity assay) is a diagnostic biopsy of the uterine lining aimed at determining the precise “window of implantation” — the time when the endometrium is most receptive to embryo implantation. In donor sperm IVF cycles, even though the sperm is donor, successful pregnancy still depends on perfect synchronization between embryo and uterine receptivity. In Korea, fertility centers offer this test using high-precision molecular diagnostics, RNA sequencing, AI-supported analysis, and integration with ultrasound and hormonal monitoring, all within a tightly controlled reproductive medicine framework.
Purpose & Benefits
The test’s purpose is to identify whether the endometrium is appropriately prepared (receptive) at a specific time and to adjust embryo transfer timing accordingly. Its potential benefits include:
- Pinpointing the optimal timing for embryo transfer, avoiding transfers outside the receptive window
- Reducing wasted implantation attempts due to timing mismatch
- Enhancing clinical pregnancy rates in patients with previous failed transfers despite good embryos
- Personalizing embryo transfer timing rather than relying on standardized schedules
- Providing additional insight into endometrial molecular health and function
However, it’s important to note that while many clinics promote ERA, clinical evidence remains mixed, and the test is often reserved for selected cases (e.g., repeated implantation failure).
Ideal Candidates
The Endometrial Receptivity Test is most appropriate for:
- Patients with repeated implantation failure (RIF) despite morphologically good embryos
- Women who have had multiple embryo transfers that failed without a clear cause
- Couples using donor sperm or donor egg IVF cycles who want maximal precision in timing
- Individuals in whom prior cycles suggested possible displaced implantation windows
- Patients willing to invest in an additional diagnostic step to refine their IVF protocol
Possible Risks & Complications
Because the procedure is minimally invasive, risks are modest:
- Mild cramping or discomfort during or after the endometrial biopsy
- Light spotting or minimal bleeding for a day or two
- Slight risk of infection (very rare, with sterile technique)
- The possibility of an inconclusive test result (neither receptive nor reliably classifiable)
- Emotional and financial burden if the test does not lead to improved outcomes
Korean fertility centers typically conduct the biopsy under ultrasound guidance and strict sterility to minimize risk.
Diagnostic Techniques Used
The test relies on advanced molecular and diagnostic technologies:
- Endometrial biopsy at a predetermined time (often after progesterone administration)
- RNA extraction and sequencing / transcriptomic analysis of hundreds of genes associated with receptivity
- AI and algorithmic comparison of gene expression against established receptive and nonreceptive profiles
- Integration with imaging (e.g., Doppler blood flow, ultrasound) and hormone levels to corroborate findings
- Classification of endometrium as receptive, pre-receptive, or post-receptive, guiding the timing of embryo transfer
Korean fertility laboratories often integrate high-throughput genetic equipment, AI pattern recognition, and rapid turnaround processing for these tests.
Recovery & Aftercare
Recovery is quick and minimal:
- Patients may resume normal activity immediately after the biopsy
- Mild cramping or spotting may last a day or two
- Avoid strenuous physical activity and sexual intercourse for a short period (as advised)
- Follow-up consultation to review results and plan the next embryo transfer cycle based on the test outcome
There is no extended downtime, as the test is an outpatient procedure.
Results & Longevity
- The test result typically falls into one of three categories: receptive, pre-receptive, or post-receptive, indicating how the endometrium’s timing aligns with progesterone exposure.
- Based on the finding, clinicians adjust the progesterone timing for the upcoming transfer to align with the patient’s personalized window
- If properly validated, the receptive window may remain stable across cycles, allowing replication in future transfers
- However, long-term evidence on improvements in live birth rates is still debated—some studies suggest that ERA does not uniformly improve outcomes in all patients
- In selected cases (especially RIF), ERA-guided transfer may improve implantation efficiency relative to standard timing
Treatment Process In Korea
In Korean fertility clinics, the process typically proceeds as follows:
- Pre-cycle assessment (hormone levels, ultrasound) and planning of a mock cycle or preparatory hormone regimen
- Progesterone and estrogen administration to mimic a transfer cycle
- Endometrial biopsy performed at the specific time when embryo transfer would otherwise occur
- Sample sent to a molecular diagnostics lab for gene expression profiling
- AI algorithm and specialist interpretation determine whether the biopsy was in the receptive phase or shifted
- A personalized embryo transfer schedule is created for the next cycle (e.g. adjust day of progesterone start or transfer timing)
- Embryo transfer is done in a subsequent cycle precisely aligned with the determined window
What distinguishes Korea:
- Use of AI-assisted genetic diagnostics and fast turnaround molecular labs
- Integration of ERA with other advanced reproductive tests (endometrial blood flow, uterine imaging)
- Clinics with robust quality control, regulatory oversight, and donor sperm IVF infrastructure
- High technical proficiency, minimal biopsy trauma, and precision scheduling
- International patient support and streamlined logistics for fertility tourists
These features help Korea offer ERA and embryo transfer with a high level of customization and reliability.
Cost Range
Estimated cost ranges in Korea:
- ERA test (molecular biopsy only): USD 800 – 1,200
- ERA combined with additional endometrial diagnostics (e.g. Doppler imaging, microbiome testing): USD 1,200 – 1,800
- Bundled packages (ERA + embryo transfer planning) may cost more, depending on clinic
Because not all clinics offer ERA as a standalone service, it is often priced as an add-on in IVF/FET packages.
Popular Clinics
Some Korean fertility clinics known to offer Endometrial Receptivity Testing include:
- CHA Fertility Center (Seoul) — reputed for ERA and genomic fertility customization
- Maria Fertility Hospital — integrated fertility center with molecular diagnostics
- MizMedi Women’s Hospital — known for combining ERA with advanced transfer planning
- Seoul National University Hospital – Reproductive Medicine Unit — strong in research and advanced diagnostics
- Specialized fertility centers in Seoul and major medical zones offering ERA as part of precision IVF programs
