How an Endometrial Receptivity Analysis can Improve Fertility

What is an Endometrial Receptivity Analysis (ERA)?

An Endometrial Receptivity Analysis (ERA) is a molecular test that helps determine when your uterine lining is most receptive to embryo implantation. This is a short period known as your “window of implantation.”

By analyzing gene expression from a small sample of the endometrium, the ERA aims to pinpoint the best time to transfer an embryo for the highest chance of success.

How Does an Endometrial Receptivity Analysis Work?

The ERA test involves taking a small biopsy of the uterine lining after following a standard frozen embryo transfer (FET) hormone protocol. This will be done in an outpatient procedure at a doctor’s office.

This tissue is analyzed to measure the activity of hundreds of genes related to endometrial receptivity. Based on those gene patterns, the result classifies the lining as:

• Receptive – ready for embryo implantation
• Pre-receptive – not yet ready
• Post-receptive – the optimal window has already passed

If your result is pre- or post-receptive, your provider can adjust the timing of progesterone exposure to schedule a personalized embryo transfer (pET) tailored to your unique implantation window.

How Does ERA Help with Fertility Treatments?

In standard IVF and FET cycles, the embryo transfer is timed using ultrasound and blood hormone levels.

The ERA adds an extra layer of precision by using gene expression data to identify the optimal transfer day. The goal is to reduce implantation failure when high-quality embryos do not implant despite appearing healthy and normal.

The ultimate goal is to increase the likelihood of a successful IVF cycle.

Who benefits from an ERA?

The ERA test may be most useful if:

• You’ve had multiple failed embryo transfers despite transferring genetically normal (PGT-tested) embryos. One 2025 study found that for women who had experienced multiple failures, ERA-guided transfers yielded a 48.2% live birth rate, compared to 26.1% without guidance.
• Your uterus appears normal on imaging, and there are no other identifiable causes of implantation failure
• You and your provider want to explore whether transfer timing could be a contributing factor

For most patients:

Large-scale studies have not found that ERA-guided transfers lead to a significant improvement in live birth rates compared with standard transfer timing.

Where is the ERA performed?

ERA tests are available at all CNY Fertility full-service locations, or can often be done at your local OBGYN. 

Endometrial Receptivity Analysis: The Bottom Line

The aim of the ERA test is to personalize your embryo transfer by identifying the best implantation window for you.

While it’s an exciting advancement that offers more precision, it may not be effective for everyone.

Most studies show that ERA does not increase live birth rates for first-time IVF patients or those without prior failed transfers.

However, for patients with repeated implantation failures and no other clear explanation, an ERA-guided transfer may offer valuable insight and a higher chance of success.

If you’ve experienced failed embryo transfers and are wondering whether the ERA could help, schedule a consultation with our team to review your history, discuss your options, and help personalize your next step on the path to pregnancy.