Endometrial receptivity array before frozen embryo transfer cycles: a systematic review and meta-analysis

Objective To investigate the impact of endometrial receptivity array (ERA) before frozen embryo transfer in patients undergoing in vitro fertilization (IVF). There is a lack of consensus regarding the use of ERA for increasing the success rate of IVF cycles, mainly in terms of the live birth rate. Design PubMed, Web of Science and Embase were searched from inception up to February 15, 2022. Setting Not applicable. Patient(s) Patients undergoing ERA vs no ERA before frozen embryo transfer. Intervention(s) Only comparative studies evaluating pregnancy rates of patients undergoing frozen embryo transfer cycles with or without prior ERA were included. Inter-study heterogeneity was also assessed using Cochrane’s Q test and the I2 statistic. The random-effects model was used to pool the odds ratio (OR) with the corresponding 95% confidence intervals (CIs). Subgroup analyses were performed to investigate the impact of ERA on pregnancy rates according to the number of previous embryo transfer (ET) failures (≤ 2 previous failed ETs vs. > 2 failed ETs, defined as recurrent implantation failure). Separate analyses were performed according to the study design and adjustment for confounders. Main Outcome Measures(s) The primary outcomes of the study were live birth rate and/or ongoing pregnancy rate. Implantation rate, biochemical pregnancy rate, clinical pregnancy rate, and miscarriage rate were considered secondary outcomes. Result(s) Eight studies (representing data on n = 2,784 patients; n = 831 had undergone ERA and n = 1,953 without ERA) were found to be eligible for this meta-analysis. The live birth or ongoing pregnancy rate for the ERA group was not significantly different compared with the non-ERA group (OR, 1.38; 95% CI, 0.79–2.41; I2 83.0%), nor was a difference seen in subgroup analyses based on the number of previous failed ETs. The rates of implantation, biochemical pregnancy, clinical pregnancy, and miscarriage were also comparable between the ERA and the non-ERA groups. After separate analyses according to the study design and adjustment for confounding factors, overall pooled estimates remained statistically nonsignificant. Conclusion(s) The findings of the current meta-analysis did not reveal a significant change in the rate of pregnancy after IVF cycles using ERA, and it is not clear whether ERA can increase the pregnancy rate or not. Systematic review registration Prospectively registered in PROSPERO (CRD42022310862). To investigate the impact of endometrial receptivity array (ERA) before frozen embryo transfer in patients undergoing in vitro fertilization (IVF). There is a lack of consensus regarding the use of ERA for increasing the success rate of IVF cycles, mainly in terms of the live birth rate. PubMed, Web of Science and Embase were searched from inception up to February 15, 2022. Not applicable. Patients undergoing ERA vs no ERA before frozen embryo transfer. Only comparative studies evaluating pregnancy rates of patients undergoing frozen embryo transfer cycles with or without prior ERA were included. Inter-study heterogeneity was also assessed using Cochrane’s Q test and the I2 statistic. The random-effects model was used to pool the odds ratio (OR) with the corresponding 95% confidence intervals (CIs). Subgroup analyses were performed to investigate the impact of ERA on pregnancy rates according to the number of previous embryo transfer (ET) failures (≤ 2 previous failed ETs vs. > 2 failed ETs, defined as recurrent implantation failure). Separate analyses were performed according to the study design and adjustment for confounders. The primary outcomes of the study were live birth rate and/or ongoing pregnancy rate. Implantation rate, biochemical pregnancy rate, clinical pregnancy rate, and miscarriage rate were considered secondary outcomes. Eight studies (representing data on n = 2,784 patients; n = 831 had undergone ERA and n = 1,953 without ERA) were found to be eligible for this meta-analysis. The live birth or ongoing pregnancy rate for the ERA group was not significantly different compared with the non-ERA group (OR, 1.38; 95% CI, 0.79–2.41; I2 83.0%), nor was a difference seen in subgroup analyses based on the number of previous failed ETs. The rates of implantation, biochemical pregnancy, clinical pregnancy, and miscarriage were also comparable between the ERA and the non-ERA groups. After separate analyses according to the study design and adjustment for confounding factors, overall pooled estimates remained statistically nonsignificant. The findings of the current meta-analysis did not reveal a significant change in the rate of pregnancy after IVF cycles using ERA, and it is not clear whether ERA can increase the pregnancy rate or not.