Purpose

This prospective study investigates the correlation between vaginal microecology and pregnancy outcomes and explores their impact on endometrial microbiota composition during frozen embryo transfer (FET) cycles. Additionally, the impact of transvaginal Lactobacillus supplementation on reproductive outcomes in patients with previous failed cycles was assessed.

Methods

A total of 379 patients undergoing FET at a reproductive medicine center were categorized into clinical pregnancy (CP), miscarriage (MISC), and non-pregnant (NP) groups. Vaginal specimens were collected for microecological evaluation prior to embryo transfer. Endometrial microbiota samples were obtained during embryo transfer for 16S rRNA gene sequencing analysis to assess endometrial microbiota composition. Vaginal microecological indicators, including pH, Lactobacillus dominance, and leukocyte esterase activity, were measured. Transvaginal Lactobacillus supplementation was investigated in 60 patients with previous failed cycles.

Results

Vaginal microecology significantly correlated with pregnancy outcomes, with normal microecology associated with a higher clinical pregnancy rate. Vaginal pH and leukocyte esterase activity were significantly associated with clinical pregnancy. Furthermore, vaginal microecological differences significantly impacted endometrial microbiota composition. However, no significant differences were observed in endometrial microbiota composition among the CP, MISC, and NP groups. Notably, transvaginal Lactobacillus supplementation increased the clinical pregnancy rate without affecting the miscarriage rate.

Conclusion

This study highlights that normal vaginal microecology, characterized by lower pH and leukocyte esterase negativity, is associated with a higher likelihood of clinical pregnancy following FET. Importantly, vaginal microecological differences influence endometrial microbiota composition. Moreover, transvaginal Lactobacillus supplementation appears promising in improving clinical pregnancy rates in patients with previous failed cycles. These findings contribute to a better understanding of the interplay between vaginal and endometrial microbiota and offer potential interventions to enhance reproductive success in assisted reproductive technologies.

中文翻译：

---

冷冻胚胎移植周期中阴道微生态差异对妊娠结局和子宫内膜微生物群的影响

目的

这项前瞻性研究调查了阴道微生态与妊娠结局之间的相关性，并探讨了它们在冷冻胚胎移植（FET）周期期间对子宫内膜微生物群组成的影响。此外，还评估了经阴道补充乳酸菌对先前周期失败的患者生殖结果的影响。

方法

共有 379 名在生殖医学中心接受 FET 的患者被分为临床妊娠 (CP)、流产 (MISC) 和非妊娠 (NP) 组。在胚胎移植前收集阴道标本进行微生态评估。在胚胎移植过程中获得子宫内膜微生物群样本，用于 16S rRNA 基因测序分析，以评估子宫内膜微生物群组成。测量阴道微生态指标，包括pH值、乳酸菌优势和白细胞酯酶活性。对 60 名先前周期失败的患者进行了经阴道补充乳酸菌的研究。

结果

阴道微生态与妊娠结局显着相关，正常微生态与较高的临床妊娠率相关。阴道pH值和白细胞酯酶活性与临床妊娠显着相关。此外，阴道微生态差异显着影响子宫内膜微生物群的组成。然而，CP、MISC 和 NP 组之间的子宫内膜微生物群组成没有观察到显着差异。值得注意的是，经阴道补充乳酸菌增加了临床妊娠率，而不影响流产率。

结论

这项研究强调，以较低 pH 值和白细胞酯酶阴性为特征的正常阴道微生态与 FET 后临床妊娠的较高可能性相关。重要的是，阴道微生态差异影响子宫内膜微生物群的组成。此外，经阴道补充乳酸菌似乎有望提高先前周期失败的患者的临床妊娠率。这些发现有助于更好地了解阴道和子宫内膜微生物群之间的相互作用，并提供潜在的干预措施，以提高辅助生殖技术的生殖成功率。