Screening for bacterial vaginosis and cervicitis aimed at preventing premature delivery

Microbiota dynamics, metabolic and immune interactions in the cervicovaginal environment and their role in spontaneous preterm birth

Differences in the cervicovaginal microbiota are associated with spontaneous preterm birth (sPTB), a significant cause of infant morbidity and mortality. Although establishing a direct causal link between cervicovaginal microbiota and sPTB remains challenging, recent advancements in sequencing technologies have facilitated the identification of microbial markers potentially linked to sPTB. Despite variations in findings, a recurring observation suggests that sPTB is associated with a more diverse and less stable vaginal microbiota across pregnancy trimesters. It is hypothesized that sPTB risk is likely to be modified via an intricate host-microbe interactions rather than due to the presence of a single microbial taxon or broad community state. Nonetheless, lactobacilli dominance is generally associated with term outcomes and contributes to a healthy vaginal environment through the production of lactic acid/maintenance of a low pH that excludes other pathogenic microorganisms. Additionally, the innate immunity of the host and metabolic interactions between cervicovaginal microbiota, such as the production of bacteriocins and the use of proteolytic enzymes, exerts a profound influence on microbial populations, activities, and host immune responses. These interplays collectively impact pregnancy outcomes. This review aims to summarize the complexity of cervicovaginal environment and microbiota dynamics, and associations with bacterial vaginosis and sPTB. There is also consideration on how probiotics may mitigate the risk of sPTB and bacterial vaginosis.

Breaking Down the Barrier: The Role of Cervical Infection and Inflammation in Preterm Birth

Approximately 40% of cases of spontaneous preterm birth (sPTB) are associated with ascending intrauterine infections. The cervix serves as a physical and immunological gatekeeper, preventing the ascent of microorganisms from the vagina to the amniotic cavity. The cervix undergoes remodeling during pregnancy. It remains firm and closed from the start until the late third trimester of pregnancy and then dilates and effaces to accommodate the passage of the fetus during delivery. Remodeling proceeds appropriately and timely to maintain the pregnancy until term delivery. However, risk factors, such as acute and chronic infection and local inflammation in the cervix, may compromise cervical integrity and result in premature remodeling, predisposing to sPTB. Previous clinical studies have established bacterial (i.e., chlamydia, gonorrhea, mycoplasma, etc.) and viral infections (i.e., herpesviruses and human papillomaviruses) as risk factors of PTB. However, the exact mechanism leading to PTB is still unknown. This review focuses on: (1) the epidemiology of cervical infections in pregnant patients; (2) cellular mechanisms that may explain the association of cervical infections to premature cervical ripening and PTB; (3) endogenous defense mechanisms of the cervix that protect the uterine cavity from infection and inflammation; and (4) potential inflammatory biomarkers associated with cervical infection that can serve as prognostic markers for premature cervical ripening and PTB. This review will provide mechanistic insights on cervical functions to assist in managing cervical infections during pregnancy.

Effect of bidet toilet use on preterm birth and vaginal flora in pregnant women

OBJECTIVE

To estimate the association between bidet toilet use and preterm birth, as well as the effect of bidet toilet use on bacterial vaginosis, in pregnant women.

METHODS

Questionnaires about bidet toilet usage were sent to 2,545 women who gave birth between 2006 and 2010 in Tokyo. Crude and multivariable adjusted odds ratios (ORs) for the incidence of preterm birth (delivery at less than 37 completed weeks of gestation) and the prevalence of bacterial vaginosis between users and nonusers of the bidet toilet were calculated using data from the questionnaire and delivery records. Bacterial vaginosis was estimated by the balance of lactobacilli and nonlactobacillus microbes based on routine prenatal microbiologic test results.

RESULTS

Of 1,293 women who responded to the questionnaire, 63.3% were users of the bidet toilet. The incidence of preterm birth was 15.8% among bidet users and 16.0% among nonusers (adjusted OR 1.04, 95% confidence interval [CI] 0.72-1.48). Additionally, no association was found between bidet toilet use and bacterial vaginosis (adjusted OR 0.96, 95% CI 0.70-1.33).

CONCLUSION

Normal use of the bidet toilet by pregnant women poses no clinical health risk for preterm birth and bacterial vaginosis.

Possible association between screening BV at the prenatal visit and reduced cervical cerclage: multi-center questionnaire in Hokkaido, Japan

AIMS

To study the screening frequency for cervical cancer, Chlamydia trachomatis (CT) infection, and bacterial vaginosis (BV) among pregnant women, and to study the association between administration of these three screening tests and performance of cervical cerclage (CC) in Hokkaido during 2004.

METHODS

Questionnaires were mailed to 70 clinics providing prenatal care only and to 113 hospitals providing prenatal care and performing deliveries. Responses were obtained anonymously.

RESULTS

A total of 6744 pregnant women received prenatal care at the 36 responding clinics and 24 050 deliveries were performed at the 56 hospitals. The percentage of clinics that screened all pregnant women for cervical cancer, CT infection or BV was 66.7%, 69.4% and 33.3%, respectively, and the corresponding percentages among the hospitals were 87.5%, 87.5% and 57.1%, respectively. Pregnant women found to have CT infection or BV, were all treated. Screening for cervical cancer or CT infection was not associated with the frequency of CC. On the other hand, screening for BV was significantly associated with the frequency of CC (P = 0.0006). The frequency of emergency CC was 0.8% among women who received prenatal care at hospitals that did not perform BV screening, while it was only 0.2 or 0.3% among women who received prenatal care at hospitals that performed BV screening on all pregnant women or on those women who were suspected of having BV, respectively.

CONCLUSION

Our results suggest that the frequency of emergency CC may be reduced in women who receive BV screening and subsequent treatment of positive cases during pregnancy.

Metronidazole with Lactacyd vaginal gel in bacterial vaginosis

AIM

To assess the efficacy and tolerability of lactic acid (Lactacyd vaginal gel; LVG) when given as an adjunct to metronidazole in the treatment of bacterial vaginosis (BV) among Filipino patients.

METHODS

A multicenter, open-labeled, controlled, randomized, three-arm comparative study on 90 women aged 18 years or over with clinically and microbiologically proven BV.

RESULTS

The lactobacilli colony count significantly increased over time in all three arms. At day 14, growth of lactobacilli was significantly higher among patients in the lactic acid gel and combination treatment arms. Significant reduction of malodorous vaginal discharge (whiff test) and lowest recurrence of BV were noted in the metronidazole plus lactic acid gel arm. Regarding disappearance of signs of BV, there was significant decrease in the pH level and frequency of clue cell positive patients across time but was not significantly different across treatment groups. Only one patient (3%, 1/60) among those who received lactic acid gel complained of increased curd-like discharge. Six patients (10%, 6/60) who received metronidazole complained of epigastric pain/discomfort, dizziness and dyspnea.

CONCLUSIONS

Lactic acid gel (LVG) is safe and as efficacious as metronidazole in the treatment of BV. There is evidence that LVG when combined with metronidazole is superior to metronidazole alone in promoting lactobacilli colonization. LVG as an adjunct to metronidazole, having the least number of recurrent BV, appears to result in better long-term treatment effect on bacterial vaginosis.

Analysis of the prevalence of bacterial vaginosis and Chlamydia trachomatis infection in 6083 pregnant women at a hospital in Otaru, Japan

AIM

Our aims were to evaluate the prevalence of bacterial vaginosis (BV), Chlamydia trachomatis (C. trachomatis) infection and Mobiluncus spp. infection among pregnant women in Otaru, Hokkaido, Japan according to the month and year of the first prenatal visit, and to evaluate their risk factors.

METHODS

Six thousand and eighty-three pregnant women who were seen consecutively at our hospital between 1993 and 2000, were enrolled in the study. Vaginal and endocervical swabs were subjected to Gram stain and detection of C. trachomatis. Univariate and multivariate methods were used to investigate the association between each infection and potential risk factors including age, gravidity, parity, history of dilatation and curettage (D & C), and history of natural abortion.

RESULTS

The annual rate of BV increased from 13.6% in 1993 to 21.4% in 2000. The annual rate of C. trachomatis infection was relatively constant. The prevalence of bacterial vaginosis, C. trachomatis infection and Mobiluncus spp. infection over the 8-year period was 18.2%, 4.2%, and 4.1%, respectively. The prevalence of the three infections was significantly higher among teenagers and among women with a history of D & C. The prevalence of C. trachomatis and Mobiluncus spp. infections was significantly higher among women with no history of delivery. BV was not associated with parity on multivariate analysis. The monthly prevalence of BV was significantly higher in May than in December, and the monthly prevalence of C. trachomatis infection was high in August.

CONCLUSION

The differences in the annual and monthly infection patterns between BV and C. trachomatis infection suggest that the etiologies of the two infections differ.

High-risk sexual behaviours and genital infections during pregnancy

This article describes the sexual behaviours of some pregnant women that contribute to vaginal and cervical infections, and describes their lack of awareness about the dangers associated with sexually transmitted infections during pregnancy. It presents a subanalysis of data from a principal epidemiological study of the association between preterm delivery and genital hygiene habits and sexual behaviour during pregnancy. One-hundred and nine postpartum women were questioned about high-risk sexual behaviours during their pregnancies, their partner's sexually transmitted disease status and their knowledge about the effect of sexually transmitted infections on their pregnancy. Global concerns about the prevalence, diagnosis and treatment of cervical and vaginal infection from sexually transmitted diseases are discussed. The dangers associated with high-risk sexual behaviours during pregnancy, and recommendations for clinicians, are included.

Does chondroitin sulfate defend the human uterine cervix against ripening in threatened premature labor?

OBJECTIVE

This study was undertaken to investigate changes in chondroitin sulfate levels in the cervix and the physiologic role of chondroitin sulfate isomers in the process of cervical ripening.

STUDY DESIGN

Uterine cervical mucus samples were obtained from 57 women (7 nonpregnant women, 19 at preterm gestation, 9 at term gestation, 16 during the first stage of term labor, and 6 with threatened premature labor). Chondroitin sulfate isomer (chondroitin 0-sulfate, 4-sulfate, and 6-sulfate) concentrations in cervical mucus were measured by high-performance liquid chromatography. The effect of exogenous chondroitin sulfate on hyaluronidase activity in cervical mucus was evaluated by gel permeation chromatography of fluorolabeled hyaluronic acid.

RESULTS

Chondroitin sulfate concentrations in cervical mucus were increased significantly (P <. 05) in the threatened premature labor group compared with the preterm and term groups. However, the same finding was not observed in the first stage of term labor. Exogenous chondroitin sulfate inhibited hyaluronidase activity in mucus.

CONCLUSION

Chondroitin sulfate may defend against cervical ripening in threatened premature labor.