Sequential embryo transfer combined with intrauterine perfusion improved pregnancy outcomes in patients with recurrent implantation failure.

"Declarations Ethical approvalThe Ethics Committee of Zhuzhou Hospital Affiliated to Xiangya School of Medicine, Central South University, approved the study (ZZCHEC2022042-01). The privacy and personal identity information of the subjects are protected. Exemption from informed consent will not have adverse effects on the rights and health of the subjects. The ethics committee of Zhuzhou Hospital Affiliated to Xiangya School of Medicine, Central South University unanimously agreed to exempt informed consent. The study was conducted in accordance with the ethical standards of the Declaration of Helsinki. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding Grant support was provided by the Natural Science Foundation of Hunan Province (No. 2022JJ50102, 2021JJ50070) and the Health and Family Planning Commission of Hunan Province (No. 202205034020)."