Aetiology of preterm labour: bacterial vaginosis (original) (raw)
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Bacterial Vaginosis and Preterm Birth: A Comprehensive Review of the Literature
Journal of Nurse-Midwifery, 1998
Preterm low birth weight is the major determinant of infant morbidity and mortality. Numerous studies have linked bacterial vaginosis (BV) with preterm birth and low birth weight (LBW), especially among black women. This article reviews the published literature to provide clear evidence that BV is an independent risk factor for preterm birth and LBW. Pregnant black women are especially at risk, having nearly three times the level of BV as pregnant white women. Compounding the problem is the fact that half the population of women with BV are asymptomatic, and current standard antenatal procedures do not provide for screening for BV. By reviewing BV treatment literature, this article also provides evidence that treatment for BV is effective and that the identification and treatment of BV in pregnant women can lead to substantial reduction in the high rates of preterm birth and LBW.
Clinical Microbiology: Open Access, 2016
Background: This study was conducted to investigate whether screening and treatment of bacterial vaginosis (BV) in early pregnancy reduces the risk of spontaneous preterm delivery or preterm premature rupture of membranes (PPROMs). Material and methods: Women were screened for BV during their first visit to the maternal health care unit. After the vaginal samples were air dried, they were sent to the gynecological department and were analyzed using Hay/ Ison modified classification. Eligible women were those who lived in Skaraborg County and delivered at Skaraborgs Hospital in Skövde, Sweden. The women were divided into two groups, namely, screened women (with BV or with lactobacilli flora) and unscreened women. Women with BV were offered treatment with vaginal clindamycin. Results: During 2007-2015, 22,084 deliveries occurred at Skaraborgs Hospital; a total of 6,899 women were screened for BV, out of which 746 (10.8%) had BV flora. Survival analysis showed that women with BV had spontaneous preterm delivery significantly earlier than those with normal lactobacilli flora, even after treatment with vaginal clindamycin (log rank p=0.01). During the same period, 15,189 deliveries occurred at Skaraborgs Hospital; they were not screened for BV. The survival analysis showed that the unscreened women delivered slightly earlier than the screened women (t-test p<0.05), with mean delivery days of 239.4-241.7. Conclusion: Even though patients with BV had been treated with clindamycin, they still suffered from an increased risk of spontaneous preterm delivery as compared to women with normal lactobacilli flora. The difference between the screened women and the unscreened women could be attributed to the positive effect of the treatment of BV with clindamycin if it can be assumed that there is the same amount of untreated BV in the unscreened group.
Effect of bacterial vaginosis on preterm birth: a meta-analysis
Archives of Gynecology and Obstetrics
Purpose Bacterial vaginosis is a common genital tract disorder. It can lead to preterm birth but its contribution and extent is equivocal. Bacterial vaginosis is a treatable cause of preterm birth if diagnosed and treated correctly. The study desired to con rm the relationship between bacterial vaginosis and preterm. Methods It was a meta-analysis. Articles published from 2008 to 2018 were included. The studies conducted to measure the strength of association between Bacterial Vaginosis and Preterm Birth by any statistical test were included. Studies with only conceptual aspects and qualitative data were excluded from the meta-analysis. Four search engines were identi ed, PubMed, Google Scholar, Cochrane, and LILAC. Forest plots were plotted separately for Odds Ratio (OR) and Relative Risk. Results After extensive search 11 studies giving 14 relevant results with 20,894 participants were included. This meta-analysis proves that Bacterial Vaginosis is strongly associated with preterm birth. The risk of preterm delivery is >2-folds in women with bacterial vaginosis (OR, 2.79; 95% CI, 2.29 to 3.41). The combined or pooled risk ratio (RR) of pregnant women with bacterial vaginosis having a preterm birth or preterm delivery is 1.52 (RR, 95% C.I.=1.33 to 1.74). Conclusion Our study shows a strong association between Bacterial vaginosis and preterm birth. The study concludes that investigation for bacterial vaginosis and management accordingly should be a part of the routine examination of a pregnant woman. The health system must initiate this strategy at the earliest to reduce prevalence of preterm births and thereby neonatal mortality.
Is a change in the vaginal flora associated with an increased risk of preterm birth?
American Journal of Obstetrics and Gynecology, 2005
Objective: The purpose of this study was to determine if a change in the vaginal flora was associated with an increased risk of preterm birth, and to determine if metronidazole therapy before 32 weeks increased the risk of preterm birth. Study design: We compared cultures taken at 23 to 26 weeks of gestation with cultures taken at delivery from women enrolled in the Vaginal Infections and Preterm Birth study to analyze the association of changes in the vaginal flora with preterm birth. Results: Metronidazole therapy before 32 weeks was associated with an increased risk of preterm birth (OR 1.5, 95%CI 1.05-2.1) in an unadjusted model. A change to heavy growth of Escherichia coli or Klebsiella pneumoniae at delivery was found to be associated with preterm birth (OR 2.4, 95%CI 1.6-3.8). After controlling for race, parity, prepregnancy weight !100 pounds, smoking or drinking during pregnancy, Trichomonas vaginalis, bacterial vaginosis, chlamydia, mycoplasmas, group B streptococcus, metronidazole therapy before 32 weeks, vaginal pH O5.0, and an increase in E coli or K pneumoniae, only prepregnancy weight !100 pounds (adjusted odds ratio [AOR] 2.07, 95%CI 1.01-4.21) and increased E coli or K pneumoniae in the vagina at delivery (AOR 2.99, 95%CI 1.37-6.53) were found to be significantly associated with preterm birth. Conclusion: An increase in E coli or K pneumoniae in the vagina is an independent risk factor for preterm birth. Changes in the vaginal flora may explain the increased risk of preterm birth seen with vaginal clindamycin or oral metronidazole therapy.
Interplay of cytokine polymorphisms and bacterial vaginosis in the etiology of preterm delivery
Journal of Reproductive Immunology, 2010
Recent findings suggest that the association between inflammation-related genes and preterm delivery may be stronger in the presence of bacterial vaginosis (BV). Tumor necrosis factor alpha (TNFα) and interleukin 1 beta (IL-1β) are proinflammatory cytokines capable of inducing preterm labor in non-human primates. In this study the authors tested associations among two TNFα promoter polymorphisms (−G308A and −G238A), a single IL-1β polymorphism (+C3954T), vaginal microbial findings, and risk of preterm delivery. Data were from the Pregnancy Outcomes and Community Health (POUCH) Study (n=777 term and n=230 preterm deliveries). Vaginal smears collected at mid-pregnancy (15-27 weeks gestation) were scored according to Nugent's criteria. A Nugent score of ≥ 4 was modeled as the cut-point for intermediate and positive BV. Logistic regression was used to estimate odds ratios for associations among independent covariates (vaginal flora, genotype) and preterm delivery. Results showed that women with a Nugent Score of ≥ 4 and the TNFα −238 A/G or A/A were at increased risk of delivering preterm (race/ethnicity adjusted OR 2.6, 95% CI 1.2, 5.8). The p-value for the genotype and Nugent score interaction = 0.02. This study points to one more example of a potential gene-environment interaction in a preterm delivery pathway. Future tests of this finding will determine the robustness of these results.
Bacterial Vaginosis as a Risk Factor for Preterm Labour-An Analysis of Age and Duration of Marriage
Journal of gynecology and obstetrics, 2016
Preterm labour is the onset of labour between ≥ 24 weeks to < 37 weeks of gestation. Bacterial Vaginosis (BV) is a polymicrobial condition with predominant lactobacilli in the vaginal flora. It is an important risk factor for preterm labour with an incidence of 5-18% of all deliveries causing increased perinatal morbidity and mortality with subsequent neurodevelopmental problems as cerebral palsy. We aimed to determine the association of BV with preterm labour population. A case control study was conducted comparing the prevalence of bacterial vaginosis in women having term labour with those who had preterm delivery. Chi square test was used to compare differences in participants' age, duration of pregnancy and duration of marriage. Odd ratio and CI was calculated for the association between BV and preterm labour. Nearly half of the participants that experienced preterm labour were between 21 and 25 years old (46.7%, n = 35) and nearly half of the participants that experienced term pregnancy were between 21 and 25 years old as well (48.0%, n = 36). Additionally, the majority of participants had been married for three to four years, for those that experienced preterm labour (64.0%, n = 48) and term pregnancy (52.0%, n = 39). Furthermore, nearly half of the participants' duration of pregnancy was between 33 and 34 weeks (49.3%, n = 37) and 52.0% of participants who experienced term pregnancy had been pregnant for 37 to 38 weeks (n = 39). Women with Bacterial Vaginosis, experienced preterm labour in 26.7% cases (n = 20) as compared to those who had term pregnancy 12.0% (n = 9). BV was significantly associated with preterm labour (OR=7.3, 95% CI =1.9-27.5, P=0.003). There was no significant difference in participants' age between preterm labour and term pregnancy groups, (p value=0.880). Additionally, there was no significant difference in participants' duration of marriage between preterm labour and term pregnancy groups, (p value=0.801). Bacterial Vaginosis is a risk factor for preterm labor. The study also concluded that there is no significant association between age, duration of pregnancy and duration of marriage between preterm labour and term pregnancy groups.
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2003
Objectives: Assess the predictive values of bacterial vaginosis (BV) for preterm delivery (PD) and neonatal infection and compare them with standard markers of infection among women with preterm labour (PL). Study design: Prospective blinded study in a tertiary referral centre in Paris. Women hospitalised for PL with intact membranes at a term between 24 and 34 weeks were included. Vaginal fluid, collected at inclusion was Gram-stained, scored, and interpreted according to Nugent's criteria. Results: Out of 354 women tested, 254 had normal flora (72.3%), 76 intermediate (21.7%) and 24 BV (6.8%). A history of spontaneous miscarriage after 14 weeks was the only risk factor significantly associated with BV. BV was not significantly associated with PD < 35 weeks or neonatal infection. Very preterm delivery (before 33 weeks) was significantly associated with the flora grade (P ¼ 0:02): women with normal, intermediate and abnormal flora, respectively had 27 (10.6%), 14 (18.4%) and 6 (25.0%) births before 33 weeks. Of the markers tested, the highest risk of very preterm delivery was associated with BV (odds ratio 2.95, 95% CI (1.1-0.8.1)) and CRP > 20 mg/dl (4.23 95% CI (1.8-9.7)). Predictive value of BV for preterm birth before 33 weeks were: sensitivity 12.8%, specificity 95.0%, positive predictive value 35.3%, and negative predictive value 84.3%. Conclusions: The frequency of BV and its association with PD are probably very variable and must be interpreted differently from one population to another. While we found an association between BV results and delivery before 33 weeks, the predictive value of BV was disappointing. Although these findings reinforce the importance of a useful marker of subclinical infection, the usefulness of testing for BV in women with PL has not been demonstrated. #