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Endometrial Receptivity Analysis (ERA) is an advanced genetic test that evaluates the timing of your endometrium’s “window of implantation”. By analysing the gene expression pattern of a small sample of the uterine lining, ERA helps determine the most suitable day for embryo transfer in IVF, especially in cases of repeated implantation failure.
Usually discussed in couples with recurrent implantation failure despite good-quality embryos and a normal-appearing uterus on scan.
Endometrial Receptivity Analysis is a molecular test that studies the expression of hundreds of genes in a small biopsy of the uterine lining. Based on this profile, the lab can tell whether the endometrium is receptive or not yet / no longer receptive on the day the sample is taken.
Every woman has a limited “window of implantation” when the lining is optimally ready for an embryo to attach. In some women, this window is shifted earlier or later than the standard timing used for frozen embryo transfers.
ERA aims to identify your personal window of implantation so that a subsequent embryo transfer can be timed precisely according to your own receptivity pattern.
ERA is not routinely required for every IVF patient. It is usually considered in specific, complex cases where adjusting the timing of embryo transfer could provide additional insight and potential benefit.
The ERA test is usually done in a “mock” cycle that mimics a frozen embryo transfer cycle, followed by a personalised transfer in a later cycle.
Your IVF history, previous transfer timings, ultrasound findings and embryo quality are reviewed. If ERA is likely to add value, the mock cycle plan, costs and expectations are explained in detail.
A cycle is started where the endometrium is prepared similar to a frozen embryo transfer (FET), either with hormones (HRT cycle) or under natural/modified natural cycle, depending on your protocol. The day count and progesterone exposure are carefully tracked.
On a specific day, when a transfer would normally be done, a small biopsy of the uterine lining is taken using a thin catheter through the cervix. This is usually an OPD procedure and takes a few minutes. The sample is sent to a specialised lab for gene expression analysis.
The lab analyses the gene expression profile and reports whether the endometrium at that time was receptive, pre-receptive or post-receptive. If it is not receptive, the report typically recommends adjusting the timing of progesterone exposure (e.g. adding or reducing hours/days) for the next embryo transfer cycle.
In a subsequent FET cycle, your medications and timing are adjusted according to the ERA result to match your personalised window of implantation. A selected embryo is then transferred at the revised time, followed by a blood pregnancy test 12–14 days later.
ERA can improve understanding of endometrial timing, but it does not guarantee pregnancy. Some couples may still face challenges due to embryo quality or other factors. For others, the endometrium may already be receptive at standard timing, meaning the test mainly confirms that timing is appropriate.
ERA requires an additional mock cycle, biopsy and cost, and is usually reserved for complex cases rather than first attempts. The biopsy may cause brief cramping or light spotting but is generally safe.
In some patients, the test may suggest standard timing is already correct, which might not change the treatment plan significantly. Also, not all experts agree on its use for every repeated failure case.
ERA should be chosen after thorough counselling, once other important factors like embryo genetics, uterine cavity and hormonal profile have been carefully evaluated.
Common questions couples ask about Endometrial Receptivity Analysis.
No. ERA is usually suggested for women with recurrent implantation failure or complex histories. For many first-time or good-prognosis patients, routine ERA is not necessary and standard timing is sufficient unless problems arise later.
ERA involves an endometrial biopsy, which may cause short-lived cramping or discomfort, similar to strong period pain, in some women. The procedure is usually quick and done without anaesthesia or with simple pain relief as advised by your doctor.
A “receptive” result means that, on the tested day and protocol, your endometrium appears appropriately ready for implantation. In such cases, your future embryo transfers can usually be timed in the same way as the mock cycle, and other factors may need to be explored for implantation issues.
“Pre-receptive” suggests your lining was not yet ready, while “post-receptive” indicates the receptive window may have already passed. In both situations, the report usually recommends adjusting the length of progesterone exposure (for example, adding or removing hours/days) to align future transfers with your personalised window of implantation.
No. ERA helps optimise timing, but pregnancy also depends on embryo quality (including genetics), uterine health and overall maternal factors. It is an additional tool to personalise treatment, not a guarantee of success.
Share your transfer history, embryo details and scan reports with our team to understand whether ERA is appropriate for you and how its results could refine the timing of your next embryo transfer.