Bacterial vaginosis and preterm delivery

Bacterial vaginosis (BV) is an imbalance of vaginal flora. There is a statistical association between BV in early pregnancy and the occurrence of obstetric complications including preterm delivery. If screening and treatment of asymptomatic BV in patients at low risk are not recommended, the management of patients at high risk of prematurity is controversial. Using molecular tool, a rational and objective approach to the imbalance of vaginal flora, would reassess the relationship between VB and obstetric complications.     

Bacterial vaginosis as a risk factor for post-cesarean endometritis

Bacterial species associated with bacterial vaginosis have been isolated more frequently from endometrial cultures of patients with postpartum endometritis than expected from the prevalence of bacterial vaginosis among pregnant women. To further assess the association between bacterial vaginosis and postpartum endometritis, vaginal Gram smears were obtained from women admitted for delivery. Vaginal smears of women delivered by cesarean were scored as normal or as indicating bacterial vaginosis. Factors related independently to postpartum endometritis by multiple logistic regression analysis included maternal age less than 25 years, any duration of membrane rupture, and bacterial vaginosis. The unadjusted odds ratio for the development of postpartum endometritis associated with bacterial vaginosis (odds ratio = 6.1, 95% confidence interval 3.3-15.9) was not appreciably changed in the multivariable analysis (odds ratio = 5.8, 95% confidence interval 3.0-10.9) after adjusting for maternal age, duration of labor, and duration of membrane rupture. At the time of endometritis, Bacteroides sp, Peptostreptococcus sp, and Gardnerella vaginalis were isolated more frequently from the endometrium using a triple lumen endometrial sampling method among patients with bacterial vaginosis than among those with a normal Gram stain. Bacterial vaginosis appears to be an important risk factor for postpartum endometritis after cesarean delivery.     

Bacterial vaginosis and preterm delivery: an open question

OBJECTIVE: To evaluate the prevalence of bacterial vaginosis in a population of Italian pregnant women and to study its association with adverse pregnancy outcomes, particularly preterm delivery. STUDY DESIGN: After giving informed consent, 598 women were consecutively enrolled at their first prenatal visit (13-18 weeks of gestation). The presence of bacterial vaginosis was assessed by Gram's method at 13-18 weeks of gestation (early bacterial vaginosis) and at 28-32 weeks of gestation (late bacterial vaginosis). Univariate and multiple logistic regression models of analysis were used to assess the statistical significance of the data. RESULTS: Preterm delivery occurred in 14.7% of pregnant women positivefor bacterial vaginosis at theirfirst prenatal visit and in 6.9% of healthy women (OR 1.6, CI 1.07-2.51). In patients with bacterial vaginosis, preterm delivery occurred more often in the 36th week of gestation (78.6%). CONCLUSION: The presence of bacterial vaginosis at an early gestational age is associated with preterm delivery, although in the study population the condition did not seem to be related to great prematurity.     

Bacterial vaginosis as a risk factor for high-grade cervical lesions and cancer in HIV-seropositive women

Objective

To assess the effect of bacterial vaginosis (BV) on the risk of high-grade squamous intraepithelial lesions (HSIL) among HIV-seropositive women.

Methods

A hospital-based prospective cohort study of HIV-seropositive women was conducted in Johannesburg, South Africa from January 2005 to September 2009. Multivariate log-binomial and Poisson regressions were used to estimate prevalence and rate ratios, respectively.

Results

Among 1954 HIV-seropositive women, the baseline prevalence of HSIL was 17%. BV prevalence was high (54%) and showed no association with prevalence of HSIL (adjusted prevalence ratio, 1.12; 95% confidence intervals (CI), 0.92-1.35) nor with cervical lesion progression at follow-up visit (n = 503) (adjusted rate ratio: 1.00; 95% CI, 0.65-1.53).

Conclusion

Among HIV-seropositive women, BV was not associated with an increased risk of HSIL or cervical lesion progression.     

Bacterial vaginosis and preterm birth

Although it has been clear for more than 2 decades that bacterial vaginosis increases the risk for preterm birth in some women, it is not yet fully understood why this association exists or how best to modify the risk. Incomplete understanding of this polymicrobial condition and difficulties in classification contribute to the challenge. The relationship between altered vaginal microflora and preterm birth is likely mediated by host immune responses. Because treatment of bacterial vaginosis during pregnancy does not improve preterm birth rates, and may in fact increase them, screening and treatment of asymptomatic pregnant women is discouraged. Symptomatic women should be treated for symptom relief. This article reviews the pathophysiology of bacterial vaginosis and controversy surrounding management during pregnancy. Agents currently recommended for treatment of this condition are reviewed.     

Bacterial vaginosis and group B streptococcal colonization and preterm delivery in a low-risk population

OBJECTIVE: To evaluate the relationship between bacterial vaginosis (BV) and group B streptococcal (GBS) colonization in the 2nd trimester of pregnancy and preterm delivery. METHODS: 1,197 pregnant women between 22 and 25 weeks' gestation had a high vaginal swab for assessment of BV and GBS. Exclusion criteria were: previous preterm delivery, or mid-trimester abortion or termination of pregnancy, multiple gestation, oligo- or polyhydramnios, placenta previa, fetal abnormalities, uterine malformations, cervical incompetence, cervical cerclage, or receipt of an antibiotic effective against BV or GBS following the screening. All women had no risk factors for preterm delivery. The primary outcome measure in this analysis was spontaneous preterm delivery before 37 weeks' gestation. RESULTS: The preterm delivery rate was 8.7%, while the maternal BV and GBS colonization rates were 7.9 and 12.5%, respectively. Following adjustment for potential confounders BV was associated with an increased risk of preterm delivery (RR 2.19; CI: 1.21-3.98) (p = 0.01). On the contrary, GBS colonization was found to have a negative correlation with preterm birth (RR 0.43; 95% CI: 0.19-1.00). CONCLUSIONS: Although BV is a risk factor for preterm delivery, GBS colonization in the 2nd trimester of pregnancy has an inverse correlation with preterm delivery.     

Cervicovaginal fetal fibronectin as a marker for preterm delivery: a meta-analysis.

OBJECTIVE: We performed a meta-analysis to determine the value of cervicovaginal fetal fibronectin as a marker for preterm delivery. STUDY DESIGN: Selection criteria confined the analysis to original, English-language reports of prospective studies including women at <37 weeks' gestation with intact amniotic membranes. For the outcomes of delivery at <37 or <34 weeks' gestation or delivery within 7, 14, 21, or 28 days after fibronectin sampling, we calculated sensitivity and specificity rates for each study, for subgroups of studies, and for all studies combined. RESULTS: A total of 27 studies met our inclusion criteria. For the outcomes of delivery at <37 and <34 weeks' gestation, overall sensitivity rates were 56% and 61% and overall specificity rates were 84% and 83%, respectively. For the outcomes of delivery within 7, 14, 21, and 28 days, we calculated sensitivity rates of 76%, 68%, 61%, and 43% and specificity rates of 88%, 89%, 91%, and 93%, respectively. For the subgroup of patients with symptoms of preterm labor, sensitivity rates for delivery within 7, 14, 21, and 28 days of 89%, 78%, 76%, and 71% and specificity rates of 86%, 86%, 88%, and 83%, respectively, were calculated. CONCLUSION: Among patients with symptoms of preterm labor, cervicovaginal fetal fibronectin appears to be among the most effective predictors of preterm delivery.     

High-density vaginal Ureaplasma urealyticum colonization as a risk factor for chorioamnionitis and preterm delivery

BACKGROUND: The aim of this case control study was to investigate the influence of genital Ureaplasma urealyticum colonization on pregnancy outcome. METHODS: One hundred and seventy-two women colonized with Ureaplasma urealyticum without co-existing other infections and 123 women with negative cultures for Ureaplasma urealyticum were enrolled. In a multivariate analysis the influence of quantitative Ureaplasma urealyticum colonization level was determined. RESULTS: Compared to the negative women increasing colonization with Ureaplasma urealyticum was associated with a significant decrease of birth weight (p<0.0001) and gestational age (p<0.0001) and with a significant increase of chorioamnionitis (p<0.0001) and preterm delivery (p<0.001). In a multivariate analysis high-density Ureaplasma urealyticum colonization was an independent risk factor for chorioamnionitis and preterm delivery, whereas low colonization levels had no effect on an adverse outcome of pregnancy. CONCLUSIONS: The degree of colonization with Ureaplasma urealyticum correlates strongly with an adverse effect on pregnancy outcome.     

Previous experience of induced abortion as a risk factor for fetal death and preterm delivery

As part of a community-based study in Korea to evaluate the effects of previous induced abortion on length of gestation and pregnancy outcome of subsequent pregnancies, we analyzed data obtained from January 1979 to December 1981 on pregnancies reported to family health workers in Kang Hwa Island, Korea. The preterm, live-birth rates were not significantly associated with previous induced abortion. Overall, the life table-estimated fetal death rate for women enrolled at the eighth or earlier weeks of gestation was 13.7%, 10.2% for women with no previous induced abortion and 28.9% for women with previous induced abortion. The relative risk for fetal death for women who had undergone a previous abortion was 2.8; relative risk for parous women compared to nulliparous women was 3.4. After controlling for parity, previous induced abortion was not a significant variable for fetal death rate.     

Midpregnancy vaginal fluid defensins, bacterial vaginosis, and risk of preterm delivery

OBJECTIVE: To assess relations among midpregnancy vaginal defensin levels, a component of the host innate immune response, bacterial vaginosis, and risk of preterm delivery. These relations are compared across race groups because previous studies have repeatedly shown that the prevalence of bacterial vaginosis and the risk of preterm delivery are greater in African-American women compared with that in white women. METHODS: Data are from a prospective study that enrolled pregnant women from 52 clinics in five Michigan communities. In the study subcohort, defensins (human neutrophil peptides 1, 2 and 3) and bacterial vaginosis (Nugent criteria) were measured in vaginal fluid collected at enrollment (15th through 27th week of pregnancy) from 1,031 non-Hispanic white and African-American women (787 term, 244 preterm). Preterm deliveries were categorized by clinical circumstances, ie, spontaneous and medically indicated. RESULTS: Among African Americans, vaginal human neutrophil peptides 1-3 levels greater than or equal to the median were associated with bacterial vaginosis and specifically with spontaneous preterm delivery only (adjusted odds ratio 2.3, 95% confidence interval 1.2-4.3). Once African-American women were stratified by human neutrophil peptide 1-3 levels, bacterial vaginosis added nothing to the prediction of spontaneous preterm delivery risk. None of the above associations were observed in non-Hispanic whites. CONCLUSION: The relations among human neutrophil peptide 1-3 levels, bacterial vaginosis, and preterm delivery vary by race group. In African Americans, midpregnancy human neutrophil peptide 1-3 levels were more informative to preterm delivery risk than was bacterial vaginosis, suggesting an important role for host response. In addition, elevated human neutrophil peptide 1-3 levels may be a marker for particular high-risk vaginal milieus that are not distinguished by the current bacterial vaginosis Nugent scoring system.     

Familial Mediterranean fever during pregnancy: an independent risk factor for preterm delivery

Objective

To investigate pregnancy outcome of patients with Familial Mediterranean fever (FMF).

Study design

A population-based study comparing all pregnancies of women with and without FMF between the years 1988 and 2006 was conducted. Stratified analyses, using the Mantel–Haenszel procedure and multiple logistic regression models, were performed to control for confounders.

Results

During the study period there were 175,572 deliveries, of which 239 occurred in patients with FMF. Using a multivariable analysis, the following conditions were significantly associated with FMF: preterm delivery (PTD, <37 weeks) (odds ratio (OR) = 1.5; 95% confidence interval (CI) 1.1–2.2), fertility treatments (OR = 2.5; 95% CI 1.4–4.4), recurrent abortions (OR = 2.2; 95% CI 1.5–3.2), labor induction (OR = 1.9; 95% CI 1.5–2.5) and malpresentations (OR = 1.8; 95% CI 1.2–2.8). Patients with FMF were more likely to deliver by cesarean delivery (CD) as compared to the comparison group (18.0% vs. 12.8%; P = 0.017). However, while controlling for possible confounders such as malpresentations, labor dystocia and failed induction, using multivariable analysis with CD as the outcome variable, FMF was not found as an independent risk factor for CD (adjusted OR = 1.2; 95% CI 0.8–1.8, P = 0.388). No significant differences were noted between the groups regarding perinatal outcomes such as low Apgar scores (<7) at 1 and 5 min (2.4% vs. 4.3%, P = 0.153 and 0.4% vs. 0.6%, P = 0.692; respectively), congenital malformations (5.2% vs. 4.9%, P = 0.838), or perinatal mortality (0.8% vs. 1.4%, P = 0.445). Stratified analysis, using the Mantel–Haenszel technique, was used to assess the association between FMF and PTD while controlling for possible confounders such as iatrogenic labor induction, fertility treatments, recurrent abortions and placental abruption. None of those variables explained the higher incidence of PTD in the group of patients with FMF.

Conclusion

Familial Mediterranean fever is an independent risk factor for preterm delivery. Nevertheless, perinatal outcome is comparable to the general population.     

Bacterial vaginosis: prevalence and predictive value for premature delivery and neonatal infection in women with preterm labour and intact membranes

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=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>20mg/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.     

Breech presentation is a risk factor for intrapartum and neonatal death in preterm delivery

OBJECTIVES: To determine the prevalence of malpresentation among preterm births and to evaluate the clinical significance of malpresentation as a predictor of neonatal complications in preterm delivery. STUDY DESIGN: A cross-sectional study was conducted comparing 692 nonvertex preterm deliveries of singleton births (24-36 weeks) to 4685 vertex preterm deliveries. Women with gestational age less than 24 weeks and birthweight <500 g were excluded from the study. RESULTS: The study population included 5377 women who met the inclusion criteria. The prevalence of malpresentation was 12.8% (692/5377); 73% in the breech presentation, 22% in the transverse lie, and 5% in other positions. The mean gestational age at birth was significantly lower in the nonvertex group (32.4+/- 3.5 vs. 34.2+/-2.6; P<0.0001). Higher rates of perinatal mortality (23.1% vs. 10.1%; P<0.0001) were observed in the nonvertex group when compared with vertex births, as well as other complications such as oligohydroamnion (9.2% vs. 3.2%; P<0.0001); small-for-gestational-age; (10.5% vs. 5.9%; P<0.001); congenital anomalies (11% vs. 5.9%; P<0.001); placental abruption (8.7% vs. 4. 1%; P<0.0001); placenta previa (6.8% vs. 2.5%; P<0.0001); premature rupture of membranes (25.4% vs. 16.6%; P<0.0001); chorioamnionitis (7.9% vs. 2.9%; P<0.001); prolapse of cord (2.3% vs. 0.6%; P<0.0001) and cesarean section rate (63.9% vs. 19.1%; P<0.0001). Neonatal mortality was found to be higher for breech presentation, odds ratio (OR)=4 (confidence interval [CI]=2.76-4; P<0.0001), transverse lie, OR=2.1 (1.1-4.12; P<0.02) and for other malpositions, OR=7.3 (2. 72-20; P<0.0001). After multivariate adjustment for birthweight, cesarean section, placental pathology and chorioamnionitis, a strong association remained between the presence of breech presentation and neonatal mortality, with an adjusted OR of 2.2 (CI=1.36-3.63; P<0.01). The adjusted OR for the two other groups of malpresentation was not statistically significant. CONCLUSION: Breech presentation in preterm delivery is an independent risk factor for neonatal mortality after simultaneous adjustment for birthweight, chorioamnionitis and placental pathology. Cesarean section was found to have a protective effect on neonatal mortality rates.     

Maternal and fetal IL1RN polymorphisms and the risk of preterm delivery: a meta-analysis

Objective: The aim of this study is to assess the relationship between IL1RN*2 variants and preterm delivery (PTD) risk.

Methods: Eligible studies were searched in Embase and PubMed databases from inception to November 2013. Two investigators identified relevant studies and extracted data of maternal and fetal genotype independently. Based on the evidence of functional studies, we used the dominant model to all compared studies.

Results: To maternal genotype, 269 PTDs and 688 controls were included in meta-analysis. The overall combined odds ratio for the IL1RN*2 variant and PTD was 1.91 (95% CI, 1.41–2.58). To fetal genotype, five studies of 322 PTDs and 858 term controls were included. The result for fetal genotype analysis showed increased risk of PTD, but not significantly (OR 1.33, 95% CI 0.99–1.78).

Subgroup analysis indicated that both maternal and fetal carriage of IL1RN*2 increased the risk of PTD only in studies including preterm premature rupture of membranes (PPROM), with a pooled OR 2.02 (95% CI 1.44–2.85) and 1.42 (1.02–1.99), respectively.

Conclusions: This meta-analysis suggests that maternal carriage of IL1RN*2 were associated with increased risk in PTD. PPROM may be an important confounding factor that should be taken into consideration for study of IL1RN polymorphism and PTD.