New study shows higher pregnancy and implantation rates in and implantation rates in patients with recurrent implantation failure following ERA test

An independent study from Jia et al. shows that patients with recurrent implantation failure significantly benefit from ERA-guided embryo transfers when compared to conventional frozen embryo transfer, as demonstrated by higher pregnancy and implantation rates.?

Overview?

Endometrial receptivity is crucial for successful embryo implantation and subsequent pregnancy. The endometrium expresses specific proteins when it is ready to receive an embryo - this period of optimal receptivity is called the window of implantation (WOI). Usually, this occurs between days 19 and 21 of the menstrual cycle, however every 3 out of 10 women have a displaced WOI [1].

?The ERA test determines a woman's personalised embryo transfer timing through the analysis of an endometrial sample and classifies the endometrium as receptive or non-receptive based on gene expression data.

?A recent study published in Medical Science Monitor evaluated the effectiveness of ERA in women with Recurrent Implantation Failure (RIF) by comparing the clinical outcomes of patients undergoing conventional frozen embryo transfer (FET). The researchers retrospectively assigned 281 Chinese women who had experienced at least 2 unsuccessful embryo transfer cycles into two groups - an ERA group (n=140; patients had the ERA test performed) and a conventional FET group (n=141; patients did not receive the ERA test). For patients in the ERA group, an endometrial biopsy was collected at P+5 (in an HRT cycle) or LH+7/hCG+7 (in a natural cycle), with the embryo transfer being guided by the test result. For patients in the FET group, embryo transfers were performed 120-126 hours post formation of the corpus luteum. There were no significant differences with regards to baseline patient characteristics amongst the two groups (age, BMI, number of ART attempts, endometrial thickness, and hormone levels).

The study results demonstrate higher clinical pregnancy (ERA: 50% vs. FET: 24.8%) and implantation rates (ERA: 41.7% vs. FET: 18.8%)?between the ERA and conventional FET groups. This data is consistent with previous publications that have reported improved clinical outcomes following ERA-guided embryo transfer [1][2][3]. Moreover, outcomes within the ERA group were compared between patients who received a receptive result and the embryo transfer (ET) was performed at P+5 (35%), and those who were found to be non-receptive at the ‘expected’ transfer timing, for whom the ET was carried out based on the ERA report recommendation (65%). There were no significant differences between the groups, thus demonstrating that ERA accurately predicts receptivity when this falls outside the ‘expected’ P+5 window.

Implications

This study demonstrates that ERA is an effective tool to significantly improve embryo implantation success for patients with RIF who are undergoing IVF and frozen embryo transfer. This is the first report to investigate the use of ERA in a Chinese population with RIF, demonstrating that the effectiveness of ERA is applicable to this population.?

These data could help clinicians develop standardised treatment pathways for patients with RIF, whereby ERA-guided embryo transfers could increase the chances for a successful pregnancy.

To read the study, click here.

References

1.??????Simon C, Gomez C, Cabanillas S, et al. A 5-year multicentre randomized controlled trial comparing personalized, frozen and fresh blastocyst transfer in IVF. Reprod Biomed Online. 2020;41:402-415.

2.?????Hashimoto T, Koizumi M, Doshida M, et al. Efficacy of the endometrial receptivity array for repeated implantation failure in Japan: A retrospective, two-centres study. Reprod Med Biol. 2017;16:290-96

3.?????Ruiz-Alonso M, Blesa D, Díaz-Gimeno P, et al. The endometrial receptivity array for diagnosis and personalized embryo transfer as a treatment for patients with repeated implantation failure. Fertil Steril. 2013;100:818-24