Impact of vaginal microecological differences on pregnancy outcomes and endometrial microbiota in frozen embryo transfer cycles

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.

Reconnoitering correlation between human papillomavirus infection-induced vaginal microecological abnormality and squamous intraepithelial lesion (SIL) progression

OBJECTIVE

This study aims to investigate the relationship between abnormal vaginal microecology and human papillomavirus (HPV) infection, as well as the squamous intraepithelial lesions (SIL) progression.

METHODS

A total of 383 patients diagnosed with HPV infection in our hospital between March 2017 and February 2022 were selected as the experimental group. In addition, several volunteers (n = 898) who underwent physical examination during the same period were randomly selected as the control group. Subsequently, we conducted several investigations, such as HPV detection and gene typing, examined vaginal microecological imbalances, and performed cytological examinations to analyze the correlation between microecological changes, different types of HPV infection, and SIL progression.

RESULTS

HPV detection primarily included single and high-risk types of HPV infections. Moreover, significant disparities in the vaginal microecological environment between patients with persistent HPV infection and the control group, as well as patients with low-grade and high-grade SIL (LSIL and HSIL), were observed. The regression analysis revealed a correlation between LSIL and microflora density, diversity, bacteriological vaginosis (BV), vulvovaginal candidiasis (VVC), trichomonas vaginalis (TV), sialidase, as well as Lactobacillus. In addition, we identified an association between HSIL and pH, flora density, diversity, BV, VVC, candida vaginitis (CV), leukocyte esterase, catalase, and Lactobacillus levels.

CONCLUSION

These findings revealed a significant association between abnormal vaginal microecology and both HPV infection and the SIL progression.

Vaginal microecology and its role in human papillomavirus infection and human papillomavirus associated cervical lesions

The vaginal microecology comprises the vaginal microbiome, immune microenvironment, vaginal anatomy, and the cervicovaginal fluid, which is rich in metabolites, enzymes, and cytokines. Investigating its role in the female reproductive system holds paramount significance. The advent of next-generation sequencing enabled a more profound investigation into the structure of the vaginal microbial community in relation to the female reproductive system. Human papillomavirus infection is prevalent among women of reproductive age, and persistent oncogenic HPV infection is widely recognized as a factor associated with cervical cancer. Extensive previous research has demonstrated that dysbiosis of vaginal microbiota characterized by a reduction in Lactobacillus species, heightens susceptivity to HPV infection, consequently contributing to persistent HPV infection and the progression of cervical lesion. Likewise, HPV infection can exacerbate dysbiosis. This review aims to provide a comprehensive summary of current literatures and to elucidate potential mechanisms underlying the interaction between vaginal microecology and HPV infection, with the intention of offering valuable insights for future clinical interventions.

Relationship between Cervicovaginal Microecological Changes and HPV16/18 Infection and Cervical Cancer in Women of Childbearing Age

OBJECTIVE

The current study aimed to investigate the correlation between HPV16/18 infection and the microecological characteristics of the female reproductive tract and cervical lesions and to explore the risk factors associated with cervical precancerous lesions (CIN) and cervical cancer (CC).

METHODS

A total of 326 women were selected for HPV screening, with 121 testing negative for HPV, 113 infected with HPV16/18, and 92 infected with other types of HPV. Microecological characteristics of the vaginal flora in all subjects were analyzed. Liquid-based thin layer cell (TCT) tests, genitourinary tract infection pathogen (STDs) assessments, HPV typing, and colposcopic pathological biopsies of exfoliated cervical cells were conducted.

RESULTS

Among patients with HPV infection, there was a higher detection rate of abnormal microecological indicators such as bacterial vaginosis (BV) and vaginal cleanliness. Additionally, an increased proportion of vaginal microbiota (VM) imbalance was observed. Ureaplasma urealyticum (Uu) infection in the reproductive tract was closely associated with HPV 16/18 infection and showed co-infection. Moreover, patients with BV infection and high expression of HPV mRNA were at a higher risk of persistent HPV16/18 positive infection. BV infection, Uu infection, and HPV16/18 positive infection were identified as risk factors for CIN and CC. Furthermore, BV and Uu infections promoted the development of CIN/CC in patients infected with HPV16/18.

CONCLUSIONS

Changes in vaginal microecology are strongly linked to HPV16/18 infection. BV infection, Uu infection, HPV viral load, and HPV16/18 infection are risk factors for CIN/CC. Timely treatment of BV and Uu infections, restoration of a normal vaginal microecological environment, and improvement of HPV16/18 outcomes can delay the occurrence and progression of CIN/CC.

Predictive value of abdominal wall scar score for pelvic floor function rehabilitation, vaginal microecology and complications after cesarean section

Objective

To explore the predictive value of the abdominal wall scar score for pelvic floor function rehabilitation, vaginal microecology and complications after cesarean section.

Methods

A total of 120 pregnant women who underwent cesarean section in our hospital from January to December 2022 were selected. The patients were divided into observation group (score ≥ 60, n = 52) and control group (score < 60, n = 68) according to the preoperative score of abdominal wall scar and whether the score exceeded 60. The pelvic floor function rehabilitation, vaginal microecology and complications were compared between the two groups, and the score of abdominal wall scar was evaluated by receiver operating characteristic (ROC) curve. The predictive value of pelvic floor function rehabilitation, vaginal microecology and complications after cesarean section was evaluated.

Results

There were significant differences between the two groups in postpartum class I and class II muscle fiber strength and pelvic floor muscle potential (P < 0.05). ROC curve showed that the AUC of abdominal scar score in predicting pelvic floor function rehabilitation was 0.806 (95% CI [0.684-0.927]), the specificity was 80.17%, and the sensitivity was 79.76%. There was significant difference in the abnormal rate of leukocte estrase (LE) and Acetylaminoglucosidase (NAG) between the two groups (P < 0.05). ROC curve showed that the AUC of abdominal scar score in predicting vaginal microecology was 0.871 (95% CI [0.776-0.966]), the specificity was 85.09%, and the sensitivity was 82.36%. There was significant difference in the incidence of postpartum complications between the two groups (P < 0.05). ROC curve showed that the AUC of abdominal scar score in predicting complications was 0.844 (95% CI [0.735-0.953]), the specificity was 82.27%, and the sensitivity was 81.15%.

Conclusion

The abdominal scar score has a certain effect on predicting the recovery of pelvic floor function, vaginal microecology and complications after cesarean section. Therefore, it can help the medical staff to adjust the treatment measures in time, which can be used as a means of preoperative auxiliary examination.

Role of body mass index in pregnancy outcomes after emergency cerclage for cervical insufficiency in singleton pregnant patients

BACKGROUND

The study aims were to analyze pregnancy outcomes after the use of emergency cerclage in patients with different BMIs.

METHODS

A total of 76 singleton pregnant patients who underwent emergency cerclage at a tertiary comprehensive hospital in China between Jan 2017 and Dec 2021 were retrospectively divided into an obesity group of 37 patients with BMIs ≥ 28 kg/m2 and a non-obesity group of 39 patients with BMIs < 28 kg/m2. The medical records of patients were reviewed and all relevant clinical data were further collected into an itemized data spreadsheet for various analyses.

RESULTS

Emergent cerclage, along with amnioreduction if needed, could be safely performed on both obese and non-obese pregnant women with a dilated external cervix (> 1 cm), which effectively prolonged the gestational week up to ≥ 25 weeks. Obese gravidae had shorter suture-to-delivery intervals and mean pregnancy lengths but more spontaneous preterm births before 37 weeks, and a lower live birth rate (P < 0.05). Logistic regression analysis revealed that BMI, how many times cerclages have been performed during pregnancy (frequency of cerclage) and bacterial vaginosis, aerobic vaginitis and vulvovaginal candidiasis (vaginal microecology) were significantly correlated with fetal loss (P < 0.05), while rank correlation analysis established a negative correlation between BMI values and the suture-to-delivery interval (P = 0.031).

CONCLUSIONS

Pregnant cervical insufficiency patients with BMIs > 28 kg/m2 may ill-serve the gestational outcomes and suture-to-delivery interval after their emergent cerclage. Additionally, BMI, frequency of cerclage and vaginal microecology accounted for higher fetal loss in patients who underwent emergency cerclage.

Effects of vaginal microecology and immunity on the pregnancy outcome of cervical cerclage

Objective

To investigate the effects of vaginal microecology and immune status on the pregnancy outcome of cervical cerclage.

Methods

The clinical data of 125 patients with cervical incompetence who underwent transvaginal cervical cerclage in our hospital from January 2018 to January 2021 were collected, based on which the associations of vaginal microecology and related immune cytokines (IL-1β, IL-6, IL-8 and TNF-α) with the cervical cerclage outcome were explored.

Results

All of the 125 patients had singleton pregnancies, who were aged 20–43 years, with a mean of (32.34 ± 5.17) years. The surgery was successful in 104 patients (full-term delivery or survival of premature infants), while unsuccessful in 21 patients (late miscarriage or death of premature infants), revealing a success rate of 83.20%. There were 70 full-term deliveries, 34 premature deliveries (28 survived while 6 died), and 15 late miscarriages. Univariate analysis revealed statistically significant differences in the timing of surgery, gestational age of cerclage, preoperative cervical canal length, genital tract infections and preoperative invasive procedures between the successful and unsuccessful groups (P < 0.05). Insignificant differences were found in the pre-pregnancy body mass index (BMI) (P > 0.05). According to the multivariate analysis results, cerclage timing and genital tract infections were independent risk factors for postoperative pregnancy failure (P < 0.05). The pathogen detection rates in the two groups of pregnant women were analyzed, finding significantly higher incidence of bacterial vaginosis (BV) in the unsuccessful group than in the successful group (P < 0.05). Inter-group comparison revealed that the positive rates for vaginal microenvironmental factors (LE, NAG, SNA, H₂O₂ and pH) were all significantly higher in the unsuccessful group than in the successful group (P < 0.05). Besides, the immune cytokine levels in the cervicovaginal secretions were also all significantly higher in the unsuccessful group than in the successful group (P < 0.05).

Conclusion

The pregnancy outcome of patients undergoing cervical cerclage is associated with the imbalance of vaginal microecology and the levels of IL-1β, IL-6, IL-8 and TNF-α in cervicovaginal secretions.

A meta-analysis of the relationship between vaginal microecology, human papillomavirus infection and cervical intraepithelial neoplasia

Microecology is an emerging discipline in recent years. The female reproductive tract is an important microecological region, and its microecological environment can directly affect women's cervical health. This meta-analysis aimed to analyze the effects of vaginal microecology on Human papillomavirus (HPV) infection and cervical intraepithelial neoplasia (CIN). PubMed and Web of Science were systematically searched for eligible publications from January 2000 to December 2017. Articles were selected on the basis of specific inclusion and exclusion criteria. The design and quality of all studies were evaluated using the Newcastle-Ottawa Scale (NOS). Odds ratios (ORs) with a 95% confidence interval (95% CI) were calculated. Thirteen eligible studies were selected to evaluate the association of vaginal microecology with HPV infection and CIN. The factors related to HPV infection were bacterial vaginosis (BV) (OR 2.57, 95% CI 1.78-3.71, P<0.05), Candida albicans (VVC) (OR 0.63, 95% CI 0.49-0.82, P < 0.05), Chlamydia trachomatis (CT) (OR 3.16, 95% CI 2.55-3.90, P < 0.05), and Ureaplasma urealyticum (UU) (OR 1.35, 95% CI 1.20-1.51, P < 0.05). BV was also related to CIN (OR 1.56, 95% CI 1.21-2.00, P < 0.05). This meta-analysis of available literature suggested an intimate association of vaginal microecology and HPV infection with CIN. BV, CT and UU were associated to increased HPV infection, VVC was associated to decreased HPV infection, Lactobacillus is not associated to increased HPV infection, BV was associated to increased CIN development risk. Further large-scale studies are needed to confirm our findings.