Chronic endometritis (CE) refers to chronic inflammatory condition of the endometrium. Recent studies have found that CE is closely associated with infertility, recurrent miscarriage, and recurrent implantation failure. However, there are no studies on CE prevalence in patients with first implantation failure and the outcome of re-pregnancy by assisted reproductive technology in these patients after antibiotic treatment.

To investigate CE prevalence in women who used in vitro fertilization & embryo transfer (IVF-ET) to assist in achieving a pregnancy but had failed first implantation and the impact of antibiotic treatment on the outcome of the next frozen-thawed embryo transfer in this group.

Women (n=381) who received IVF-ET to assist in achieving a pregnancy but had failed first implantation were selected from Henan Provincial People's Hospital from May 2017 to May 2021. 333 patients without CE were according to hysteroscopic and endometrial histopathological findings. 37 of CE patients were found with reversed (cured) clinical condition, but the other 11 still with unreversed (uncured) condition who were received antibiotic treatment . Clinical data and the outcome of the second assisted conception were compared between cured and uncured CE patients, as well as non-CE patients.

Cured and uncured CE patients and non-CE patients had no statistical differences in mean age, BMI, endometrial thickness on the day of embryo transfer, years of infertility, and number of embryos transferred, as well as the distribution of infertility type (P>0.05) . But they had statistical differences in success rates of embryo retransfer and pregnancy (P<0.05) . Cured CE patients and non-CE patients had higher success rates of embryo retransfer and pregnancy than did uncured CE patients (P<0.05) . There were no statistical differences in early abortion rates were found across cured and uncured CE patients and non-CE patients (P>0.05) .

CE should be treated by standard antibiotic treatment. Uncured CE may negatively influence the outcome of frozen-thawed embryo retransfer. So it is recommended that women with first implantation failure actively undergo hysteroscopy and endometrial histopathology so as to find possible causes of implantation failure.

慢性子宫内膜炎（CE）是指子宫内膜的慢性炎症。近年研究发现，CE与不孕症、复发性流产及反复种植失败密切相关，然而目前尚未有关于首次种植失败患者中CE的发生情况及抗生素治疗后该类患者再次助孕结局的研究。

探讨在体外受精-胚胎移植（IVF-ET）助孕过程中首次种植失败女性CE的发生率及抗生素治疗对其下一次冻融胚胎移植结局的影响。

收集2017年5月至2021年5月于河南省人民医院行IVF-ET助孕后首次种植失败的381例患者的临床资料。宫腔镜及内膜组织病理结果排除CE的患者归为非CE组（n=333），根据抗生素治疗后CE患者转归情况将CE患者分为CE转阴组（n=37）及CE持续阳性组（n=11），比较非CE组、CE转阴组、CE持续阳性组三组人群临床资料和再次助孕的妊娠结局。

三组年龄、BMI、移植日内膜厚度、不孕年限、移植胚胎数、不孕类型等比较，差异无统计学意义（P>0.05）。三组间胚胎种植率、临床妊娠率比较，差异有统计学意义（P<0.05）；其中非CE组、CE转阴组胚胎种植率、临床妊娠率均高于CE持续阳性组（P<0.05）。三组早期流产率比较，差异无统计学意义（P>0.05）。

确诊为CE的患者应采用规范的抗生素治疗，未治愈的CE将对再次冻融胚胎移植的结局产生不良影响；建议首次种植失败患者积极进行宫腔镜检查及病理学检查寻找可能病因。