ERA Test (Endometrial Receptivity Analysis)

Personalizing Embryo Transfer Timing for Better IVF Success

What Is the ERA Test?

The Endometrial Receptivity Analysis (ERA) is a specialized diagnostic test used to determine the optimal time for embryo transfer during an IVF cycle. It evaluates whether a woman’s endometrial lining is receptive to implantation — which is crucial for a successful pregnancy.

In simpler terms, ERA helps answer:
“Is my uterus ready to receive an embryo right now?”

Why Is Endometrial Receptivity Important?

For implantation to occur, an embryo must be transferred during a short period called the “Window of Implantation” (WOI) — typically 5–7 days after ovulation. However, about 20–30% of women have a shifted or displaced WOI, meaning their uterus might not be receptive at the usual time.

Transferring an embryo outside the ideal window can lead to:

• Failed implantation
• Repeated IVF failure
• Miscarriage

Who Should Consider the ERA Test?

The ERA test may be recommended if you:

• Have had repeated implantation failure (RIF) in IVF (typically 2–3 failed transfers)
• Have had good-quality embryos but no pregnancy
• Want to optimize timing for your first frozen embryo transfer (FET), especially if you have limited embryos or are using donor eggs

How Does the ERA Test Work?

1. Endometrial Preparation
   You undergo a mock cycle (either natural or hormone-prepared), just like you would for a frozen embryo transfer.
2. Endometrial Biopsy
   On the expected day of embryo transfer, a small biopsy of the uterine lining is taken. This is a quick, outpatient procedure, similar to a pap smear.
3. Genetic Analysis
   The biopsy sample is analyzed using advanced molecular technology to assess the expression of hundreds of genes that indicate endometrial receptivity.
4. Personalized Timing
   Results will show whether your uterus is:
   • Receptive - embryo transfer timing is correct
   • Pre-receptive - embryo transfer should be delayed
   • Post-receptive - embryo transfer should be done earlier
   Your next embryo transfer is then timed precisely based on your unique window of implantation.

Benefits of the ERA Test

• Increases chances of successful implantation
• Offers personalized embryo transfer timing
• Helps explain recurrent implantation failure