Embryo quality is often blamed for failed IVF cycles. But even the most genetically sound embryos can fail to implant if the uterus isn’t ready to receive them. That’s where endometrial receptivity – and the ERA test – comes in.
At SILK Medical, we use Endometrial Receptivity Analysis to help identify the precise timing when a patient’s uterus is most receptive, allowing us to align embryo transfer with this narrow and individual window. For many patients, especially those with unexplained implantation failure, this test helps turn unsuccessful attempts into confirmed pregnancies.
Why Endometrial Receptivity Matters
The endometrium is the inner lining of the uterus, where the embryo must implant to start a pregnancy. Each cycle, this lining thickens and becomes biochemically active in preparation for a potential pregnancy. But it’s only receptive to an embryo for a brief window – usually 3 to 5 days – known as the “window of implantation.”
For most women, this window occurs around days 19 to 21 of the menstrual cycle. However, in up to 30% of IVF patients, that timing is slightly off – even by a day – which can make all the difference. Repeated implantation failure despite high-quality embryos is often a sign that the timing between embryo development and endometrial readiness is misaligned.
What Is the ERA Test?
Endometrial Receptivity Analysis (ERA) is a molecular diagnostic test performed on a small biopsy of the endometrial lining. The sample is analyzed for the expression of 248 genes that indicate whether the uterus is in a receptive state or not. The test does not simply confirm if the uterus is healthy – it identifies the exact timing when the endometrium is primed for implantation.
The procedure is typically done in a mock cycle, without embryo transfer, to observe how the endometrium responds to hormone treatment. Based on the results, the doctor adjusts the timing of future embryo transfers, ensuring that they are done at the optimal moment for implantation.
Who Should Consider ERA Testing?
ERA is not recommended for all IVF patients – it’s a precision tool best suited for those who’ve had more than one failed embryo transfer despite good-quality embryos. It’s also relevant for patients with a history of recurrent miscarriage or those whose endometrium shows unusual thickness or structure during monitoring.
Advanced maternal age, unexplained infertility, and prior unsuccessful IVF cycles are all good reasons to consider ERA. In many of these cases, standard embryo transfer timing may be just slightly off – enough to consistently prevent pregnancy without any clear reason why.
Personalized Timing Leads to Higher Success
SILK Medical uses the ERA test as part of our custom IVF protocols. When combined with genetic screening (PGT-A) and continuous embryo monitoring through our AI-powered EmbryoScope, ERA gives our medical team even more control over the variables that influence success.
By synchronizing the embryo transfer with each patient’s individual window of implantation, we increase the odds that the embryo will successfully attach and grow. For patients who’ve previously experienced frustration or disappointment with IVF, this level of precision often shifts the outcome.
How ERA Is Integrated into IVF at SILK Medical
We typically recommend the ERA test after two or more unsuccessful embryo transfers, especially when the embryos were chromosomally normal. During the test cycle, the patient follows a standard hormone protocol, and a biopsy is taken just before a typical embryo transfer would happen. There’s no risk to future fertility, and the process is quick and well tolerated.
If the test shows that the patient’s uterus is not receptive at the standard transfer time, we adjust the hormone protocol for the next cycle – either moving the transfer forward or delaying it slightly. This adjustment has made a measurable difference for many of our patients.
ERA is offered at an additional cost and is optional. However, in certain cases it can prevent the need for multiple unsuccessful cycles, saving both emotional and financial resources in the long run.
Precision Over Guesswork
Not every patient needs ERA. But for those who do, it can be the missing piece in the IVF process. SILK Medical focuses on personalized, evidence-based treatment – and that includes finding the right time, not just the right embryo.
If you’ve had unexplained failures with IVF despite good embryo quality, the timing may be the problem. And it’s something we can test. Get in touch with our team to find out whether ERA is right for your treatment plan.
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