Endometrial Receptivity Array (ERA)

Infertility patients and doctors may be frustrated by many different challenges. One in particular, however, causes us unique angst: lack of pregnancy despite multiple transfers of CGH-normal embryos or egg donation embryos. In these cases, when the uterus appears to be normal and the endometrium appears to be prepared by ultrasound parameters, it is very difficult to understand why pregnancy is not happening. While we know that not all egg donation embryos or embryos which test normal for chromosomes will implant, once we’ve had several attempts in this clinical scenario without success, we start to wonder: what else could be contributing? What else could be going to inhibit implantation?

The Endometrial Receptivity Array (ERA) addresses this issue by examining the endometrium genetically. Most practitioners will do endometrial biopsies to rule out infection or inflammation, but the ERA tests this tissue for 238 genes. These genes are implicated in the formation of a normal endometrium which is adequately prepared to support implantation of a blastocyst. There are many papers to support the investigation of these factors and recent papers show that 88% of patients with this clinical history, who were tested, had a lining that was not adequate for implantation. The results of the testing not only tell us that the lining isn’t good enough, but tells the physician how to fix it; we either add or subtract days of progesterone support, to make the lining properly prepared.

Recent data is extremely encouraging—demonstrating a vast improvement in pregnancy rates in those patients who then adjusted their medication as indicated by the assay. This test is relatively easy; an endometrial biopsy can be performed in just a few minutes in your doctor’s office. The adjustment in protocol changes only the number of days of progesterone support before transfer; no additional medications are needed. This risk-free test and adjustment in stimulation protocol seems to be extremely effective in improving ongoing clinical pregnancy rates in many women who have suffered from repeated failures with high-quality embryos.

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