In a nutshell
This trial investigated whether a new genetic test could predict the best time to undergo embryo implantation during in-vitro fertilization (IVF).
Some women undergoing IVF experience repeated implantation failure (RIF). RIF means that the fertilized embryos introduced into the uterus fail to implant and result in miscarriage, at least 3 times. Treatment options for women with RIF are currently limited, highlighting the need to personalize IVF strategies to improve pregnancy outcomes.
Fertilized embryos inserted into the uterus need to implant themselves into the endometrium (the inner-most layer of the uterus). This tissue varies in thickness and ability to take up embryos in response to hormonal changes. Genetic analysis of endometrial tissue may help predict the optimal time for embryo transfer.
The endometrial receptivity array (ERA) test studies 238 genes responsible for regulating the function of the endometrium. ERA can predict when the endometrium is receptive (can receive embyos) or nonreceptive. Personalized embryo transfer (PET) involves introducing embryos into the uterus when the endometrium is receptive.
Methods & findings
The trial included 85 women with RIF and 25 IVF patients with normal implantation (control group). All participants had PET guided by ERA. The endometrium was found to be receptive in 74.1% of patients with RIF versus 88% in the control group at the first ERA testing. Follow-up was possible in only 29 of the RIF patients, in whom PET was performed (based on ERA results), resulting in a pregnancy rate of 51.7%. 22 RIF patients (25.9%) were tested nonreceptive, and in 15 of them a second ERA helped predict the correct time to perform embryo transfer at the next cycle. In 8 of these patients, PET performed on the day designated by the second ERA, resulted in a pregnancy rate of 50.0%.
The bottom line
These results showed that ERA could help predict the best timing for embryo transfer, based on the uterine receptivity. In women with RIF, this time-window may be elusive, stressing the importance of this tool. Personalizing embryo transfer should improve pregnancy rates, particularly in women with RIF.
The fine print
This trial only included a small number of women. Further larger-scale studies are warranted to determine the clinical role of ERA testing. This test requires a procedure to sample endometrial tissue, with a small risk of complications (bleeding, infection).
If you consider IVF, ask your doctor whether you could benefit from an ERA test.
Published By :
Fertility and Sterility
Sep 01, 2013