Personalizing the timing of transfer.
The ERA test looks at the lining of the uterus to help estimate when it's most ready for an embryo. At RMA of Michigan, we use evidence-informed testing and compassionate guidance to help personalize the timing of a frozen embryo transfer.
What is the ERA test? Endometrial Receptivity Analysis (ERA) is a test that looks at the lining of the uterus — the endometrium — to help estimate the timing when it's most receptive to an embryo. A small sample of the lining is taken and analyzed to see whether it was receptive at that point in the cycle. At RMA of Michigan in Troy, ERA is used to help personalize the timing of a frozen embryo transfer.
Understanding the ERA test
ERA — Endometrial Receptivity Analysis — examines the endometrium, the lining of the uterus where an embryo implants. The goal is to estimate the window when the lining is most receptive, so an embryo transfer can be timed to it.
In IVF, a lot of attention goes to embryo quality, but the timing of the transfer matters too. The window of receptivity can vary from person to person, and for some patients it falls slightly earlier or later than the standard timing.
ERA is used alongside an IVF cycle and a frozen embryo transfer, and it can be combined with genetic testing (PGT-A). It's often considered after a transfer hasn't been successful. Whether ERA is right for you is a conversation to have with your physician, as the research continues to evolve.
How the ERA test works, step by step
ERA adds a preparation cycle and a biopsy before a future transfer. Your specific timing is individualized to your cycle.
Preparation Cycle
Your uterine lining is prepared with hormone medication, just as it would be for a frozen embryo transfer — but no embryo is transferred this cycle.
Endometrial Biopsy
At the planned transfer point, a small sample of the lining is taken during a brief, in-office procedure.
Lab Analysis
The sample is sent to a laboratory that reads the activity of genes linked to receptivity in the lining.
Results
Your result shows whether the lining was receptive, pre-receptive, or post-receptive at the point the sample was taken.
Personalized Transfer
Your team uses the result to time a future frozen embryo transfer to your personalized window of implantation.
What the ERA results mean
An ERA result describes how the lining looked at the time of the biopsy. Here's what each possibility points to.
Receptive
The lining appeared ready at the time of the biopsy, suggesting a transfer timed to that point may align with your window of implantation.
Pre-receptive
The lining wasn't quite ready at the biopsy point, which suggests the transfer window may fall a little later in the cycle.
Post-receptive
The lining was past its most receptive point, which suggests the window may fall a little earlier in the cycle.
A personalized window
If a result is pre- or post-receptive, your team suggests an adjusted timing for a future transfer based on the findings.
A second test
A pre- or post-receptive result is sometimes followed by a second test to confirm the adjusted timing before transfer.
Synchrony
ERA can be paired with PGT-A so that a tested embryo is matched with personalized transfer timing.
When ERA may be considered
ERA isn't part of every IVF journey. It's most often discussed in specific situations, and your physician will help you decide whether it's worth pursuing.
- After one or more embryo transfers that haven't led to pregnancy, despite good-quality embryos.
- When personalizing the timing of a frozen embryo transfer could be helpful for your situation.
- Alongside other testing, such as PGT-A, as part of a fuller picture.
- As an optional step — ERA isn't recommended for everyone, and research on its benefit continues to evolve.
How ERA fits into your IVF timeline
Timing varies between patients and cycles. This is a general sequence to help you picture where ERA fits in.
Mock Cycle
Your uterine lining is prepared with hormone medication, just as it would be for a frozen embryo transfer.
Endometrial Biopsy
At the planned transfer point, a small sample of the lining is taken in a brief in-office procedure.
Lab Analysis
The sample is sent to a laboratory that reads the activity of genes linked to receptivity.
Receptive or Not
Your result shows whether the lining was receptive, pre-receptive, or post-receptive at that point.
Confirming Timing
If the result is pre- or post-receptive, an adjusted window is suggested, sometimes confirmed with a second test.
Personalized Transfer
A future frozen embryo transfer is timed to your personalized window of implantation.
ERA questions, answered
What does the ERA test actually measure?
ERA looks at the activity of genes in the uterine lining to estimate whether it was receptive at the time of the biopsy — in other words, whether the timing aligned with the window when an embryo is most likely to implant.
Is the biopsy painful?
The endometrial biopsy is a brief in-office procedure. Most people feel cramping similar to a period, and it's done without sedation. Your team can talk through what to expect beforehand.
Will I have an embryo transfer during the ERA cycle?
No. The ERA biopsy is done in a preparation cycle without a transfer. The results are then used to time a separate frozen embryo transfer in a later cycle.
Who might consider ERA?
ERA is most often discussed after a transfer hasn't been successful despite good-quality embryos, or when personalizing transfer timing could help. It isn't recommended for everyone — your physician will help you decide.
Does ERA improve the chance of pregnancy?
ERA aims to personalize the timing of transfer. Research on whether it improves outcomes for most patients is still evolving and sometimes mixed, so it's a decision to make with your physician based on your individual situation.
What is Synchrony?
Synchrony refers to combining ERA with PGT-A — pairing a tested embryo with personalized transfer timing. Your physician can explain whether combined testing makes sense for your plan.