Increased interleukin-6 concentrations in cervical secretions are associated with preterm delivery

Benefits of Premaquick® Combined Detection of IL-6/Total IGFBP-1/Native IGFBP-1 to Predict Preterm Delivery

We conducted a prospective double-blind study to compare two vaginal diagnostic methods in singleton pregnancies with threatened preterm labor (TPL) at the University Hospital of Clermont-Ferrand (France) from August 2018 to December 2020. Our main objective was to compare the diagnostic capacity at admission, in terms of positive predictive value (PPV) and negative predictive value (NPV), of Premaquick® (combined detection of IL-6/total IGFBP-1/native IGFBP-1) and QuikCheck fFN™ (fetal fibronectin) for delivery within 7 days in cases of TPL. We included 193 patients. Premaquick® had a sensitivity close to 89%, equivalent to QuikCheck fFN™, but a higher statistical specificity of 49.5% against 38.6% for QuikCheck fFN™. We found no superiority of Premaquick® over QuickCheck fFN™ in terms of PPV (6.6% vs. 7.9%), with NPV being equivalent in predicting childbirth within 7 days in cases of TPL (98.6% vs. 98.9%). Nevertheless, the combination of positive native and total IGFBP-1 and the combination of all three positive markers were associated with a higher PPV. Our results, though non-significant, support this combined multiple-biomarker approach to improve testing in terms of predictive values.

Increasing the Prediction Power of Preterm Labor using Interleukin 6 and Fetal Fibronectin as Alarming Signals in Symptomatic Patients

Background: Giving birth at preterm is considered as a bothering problem to both healthcare systems and pregnant women around the world, causing alarming levels of mortality. To avoid this issue, certain biological markers can be employed for early detection to predict the occurrence of the PTD (PTD) ahead of time for giving better medical care to the pregnant women who at risk of PTD. Objective: The current study was performed to evaluate the power of using interleukin-6 (IL-6) and fetal fibronectin (fFN) present in the cervicovaginal fluid (CVF) as predictors of the symptomatic PTD patients. Patients & Methods: In this study, 91 pregnant hospital attendees (24-34 weeks; 18-45 years old) with suggested PTD symptoms, such as abdominal pain and uterine contraction and with cervical length of less than 25mm, were participated. To detect IL-6 and fFN, vaginal swabs were collected for performing an ELISA test to later follow up with the patients within 48hrs, seven days, and 14 days from the first day of admission to the hospital.  Results: No significant association between PTD with patients age, parity, BMI, and gestational age, but significant association with previous history of PTD. There was significant association between PTD and increase the level of CVF fFN and IL-6 with best cut-off value for CVF fFN is(>45ng/ml) with (95%CI of 0.763-0.918) and accuracy of 85.2% with a sensitivity of 73.1% and specificity of 95.6% which is of high significant value (P≤0.01).While CVF of IL-6 (>231pg/ml) with (95% CI of 0.630- 0.820), with accuracy of 73.3%,  sensitivity of 50% and specificity of 96.9% which was statistically significant finding (P≤0.01).The predictive value of combined fFN and IL-6  in women at risk  of preterm labor was 84.6% with sensitivity 84.6%,specificity 92.3%, positive predictive value (PPV) 81.5%, negative predictive value (PPV) 93.8% and accuracy of 90.1%. Conclusion:  Each of fFN or IL-6 located in the CVF may provide a strong predictor of PTD; however, this prediction capability may provide an even stronger signal of detecting PTD ahead of time if both biomarkers requested at the same time.

Association between interleukin-6 levels in amniotic fluid after rupture of membranes during labour at term pregnancy and successful vaginal delivery: a prospective cohort study

We compared the mean interleukin-6 (IL-6) level in the amniotic fluid after rupture of membranes during labour at term pregnancy according to the delivery methods through prospective cohort study. Cases with premature rupture of membranes, multifetal pregnancy, and major congenital anomalies were excluded. Amniotic fluid was obtained from vaginal canal immediately after spontaneous rupture of membranes. A total of 47 cases were analysed, and 72.3% (34/47) had successful vaginal delivery. The mean concentration of IL-6 in the amniotic fluid was significantly higher in the vaginal delivery group than in the caesarean section group (5,229 pg/mL vs. 1,702 pg/mL, p = .022). The concentration of IL-6 from the amniotic fluid tended to increase as the cervical dilatation increased. The association between high IL-6 level (>2,500 pg/mL) and successful vaginal delivery was not significant after adjusting the degree of cervical dilatation in multivariate logistic regression analysis. IMPACT STATEMENTWhat is already known on this subject? Multiparity, active and strong uterine contractions, dilated cervical os, and the position of foetal head are known clinical factors affecting the successful vaginal delivery. There are few studies on markers for successful vaginal delivery in patients with labour.What do the results of this study add? The mean value of IL-6 concentration from the amniotic fluid collected from vagina immediately after rupture of membranes was significantly higher in the patients who had resulted in successful vaginal delivery than those who had failed.What are the implications are of these findings for clinical practice and/or further research? Measurement of IL-6 concentration in the amniotic fluid from vaginal canal in patients with labour might help to predict the successful vaginal delivery and shorten the time before decision of caesarean section.

AACC Guidance Document on Laboratory Testing for the Assessment of Preterm Delivery

Identifying women with preterm labor who will go on to deliver prematurely is crucial to improving outcomes for mother and baby and for saving healthcare resources. Even among those with symptoms, the number of women who deliver preterm is low, and thus the low positive predictive value (PPV) and high negative predictive value (NPV) associated with available biomarkers does not substantially reduce the uncertainty of the clinical diagnosis. While there is some promise in the use of fetal fibronectin (fFN), interleukin 6 (IL-6), or placental alpha microglobulin 1 (PAMG-1) for predicting preterm birth (PTB), their use is unlikely to provide considerable clinical value in populations with a low prevalence. To provide real clinical benefit, a biomarker must demonstrate a high PPV to allow identification of the minority of symptomatic women who will deliver prematurely. As none of the currently available biomarkers exhibit this performance characteristic, we do not recommend their routine clinical use in populations with a pre-test probability of PTB of <5%. Limiting biomarker testing to only high-risk women identified on the basis of cervical length or other characteristics will increase the pre-testprobability in the tested population, thereby improving PPV. PAMG-1 is associated with a higher PPV than fFN and may show clinical utility in populations with a higher pre-test probability, but further work is required to conclusively demonstrate improved outcomes in this patient group.

Intra-amniotic infection and sterile intra-amniotic inflammation are associated with elevated concentrations of cervical fluid interleukin-6 in women with spontaneous preterm labor with intact membranes

OBJECTIVE

To determine the concentration of interleukin-6 (IL-6) in the cervical fluid in women with spontaneous preterm labor with intact fetal membranes (PTL) complicated by intra-amniotic infection (the presence of both microbial invasion of the amniotic cavity and intra-amniotic inflammation), or sterile intra-amniotic inflammation (the presence of intra-amniotic inflammation alone).

METHODS

Eighty women with singleton pregnancies complicated by PTL between gestational ages 22 + 0 and 34 + 6 weeks were included in this retrospective cohort study. Samples of amniotic and cervical fluids were collected at the time of admission. Amniotic fluid samples were obtained via transabdominal amniocentesis, and cervical fluid was obtained using a Dacron polyester swab. Microbial invasion of the amniotic cavity was diagnosed based on the combination of culture and molecular biology methods. The concentration of IL-6 in the amniotic and cervical fluids were measured using an automated electrochemiluminescence immunoassay method. Intra-amniotic inflammation was defined as an amniotic fluid IL-6 concentration ≥3000 pg/mL.

RESULTS

The presence of intra-amniotic infection and sterile inflammation was identified in 15% (12/80) and 26% (21/80) of the women, respectively. Women with intra-amniotic infection (median: 587 pg/mL; p = .01) and with sterile intra-amniotic inflammation (median: 590 pg/mL; p = .005) had higher concentrations of IL-6 in the cervical fluid than those without intra-amniotic inflammation (intra-amniotic infection: median 587 pg/mL vs. without inflammation, median: 136 pg/mL; p = .01; sterile intra-amniotic inflammation, median: 590 pg/mL vs. without inflammation, p = .005). No differences were found in the concentrations of IL-6 in the cervical fluid between women with intra-amniotic infection and sterile intra-amniotic inflammation (p = .81).

CONCLUSION

In pregnancies with PTL, both forms of intra-amniotic inflammation are associated with elevated concentrations of IL-6 in the cervical fluid.

Interleukin (IL)-6: A Friend or Foe of Pregnancy and Parturition? Evidence From Functional Studies in Fetal Membrane Cells

Objective

Protection of the fetus within the amniotic sac is primarily attained by remodeling fetal membrane (amniochorion) cells through cyclic epithelial to mesenchymal and mesenchymal to epithelial (EMT and MET) transitions. Endocrine and paracrine factors regulate EMT and MET during pregnancy. At term, increased oxidative stress forces a terminal state of EMT and inflammation, predisposing to membrane weakening and rupture. IL-6 is a constitutively expressed cytokine during gestation, but it is elevated in term and preterm births. Therefore, we tested the hypothesis that IL-6 can determine the fate of amnion membrane cells and that pathologic levels of IL-6 can cause a terminal state of EMT and inflammation, leading to adverse pregnancy outcomes.

Methods

Primary amnion epithelial cells (AECs) were treated with recombinant IL-6 (330, 1,650, 3,330, and 16,000 pg/ml) for 48 h (N = 5). IL-6-induced cell senescence (aging), cell death (apoptosis and necrosis), and cell cycle changes were studied using flow cytometry. Cellular transitions were determined by immunocytochemistry and western blot analysis, while IL-6 signaling (activation of signaling kinases) was measured by immunoassay. Inflammatory marker matrix metalloproteinase (MMP9) and granulocyte-macrophage colony-stimulating factor (GM-CSF) concentrations were measured using a Fluorokine E assay and ELISA, respectively. Amniotic membranes collected on gestational day (D) 12 and D18 from IL-6 knockout (KO) and control C57BL/6 mice (N = 3 each) were used to determine the impact of IL-6 on cell transitions. Fold changes were measured based on the mean of each group.

Results

IL-6 treatment of AECs at physiologic or pathologic doses increased JNK and p38MAPK activation; however, the activation of signals did not cause changes in AEC cell cycle, cellular senescence, apoptosis, necrosis, cellular transitions, or inflammation (MMP9 and GM-CSF) compared to control. EMT markers were higher on D18 compared to D12 regardless of IL-6 status in the mouse amniotic sac.

Conclusion

Physiologic and pathologic concentrations of IL-6 did not cause amnion cell aging, cell death, cellular transitions, or inflammation. IL-6 may function to maintain cellular homeostasis throughout gestation in fetal membrane cells. Although IL-6 is a good biomarker for adverse pregnancies, it is not an indicator of an underlying pathological mechanism in membrane cells.

Vaginal Mycoplasmataceae colonization and association with immune mediators in pregnancy

OBJECTIVE

To determine the prevalence of Mycoplasmataceae species in pregnant women and evaluate their association with immune system mediators.

METHODS

Women were prospectively enrolled between 16-22 weeks' gestation. Vaginal swabs were self-collected and analyzed with PCR for Mycoplasma hominis (MH) and Mycoplasma genitalium (MG) as well as Ureaplasma urealyticum (UU) and Ureaplasma parvum (UP) (collectively, Myc). Immune mediators were measured via Luminex multiplex assay. Women with vaginal Mycoplasmataceae were compared to women without Myc, and women with Mycoplasma species (MH or MG) were compared to women without MH or MG. Linear regression models were used to investigate the relationship of the presence of Mycoplasmataceae on log-transformed immune mediators while controlling for confounders using propensity scores.

RESULTS

One-hundred-twenty women were enrolled and had complete lab data available. Colonization was 20.8, 2.5, 10.0, and 48.3% for MH, MG, UU, and UP, respectively. Women with any Mycoplasmataceae were more likely to be younger, of the Black race, and have public insurance. There were no significant differences in immune mediators between women with vaginal Mycoplasmataceae versus those without. After controlling for confounders, women with MH and/or MG had significantly elevated levels of IL-1β compared to women without MH or MG (estimate =  1.12; 95% CI =  0.33, 1.93). There were no other significant differences in immune mediators in women with MH and/or MG compared to those without.

CONCLUSIONS

Colonization rates were highest for UP and lowest for MG. Higher IL-1β levels were seen in the presence of MH and/or MG, indicating that these less frequently encountered organisms may incite a stronger host response. There were no other significant differences in immune mediator levels.

Infection/inflammation-associated preterm delivery within 14 days of presentation with symptoms of preterm labour: A multivariate predictive model

Multi-marker tests hold promise for identifying symptomatic women at risk of imminent preterm delivery (PTD, <37 week’s gestation). This study sought to determine the relationship of inflammatory mediators and metabolites in cervicovaginal fluid (CVF) with spontaneous PTD (sPTD) and delivery within 14 days of presentation with symptoms of preterm labour (PTL). CVF samples from 94 (preterm = 19, term = 75) singleton women with symptoms of PTL studied between 19⁺⁰–36⁺⁶ weeks’ gestation were analysed for cytokines/chemokines by multiplexed bead-based immunoassay, while metabolites were quantified by enzyme-based spectrophotometry in a subset of 61 women (preterm = 16, term = 45). Prevalence of targeted vaginal bacterial species was determined for 70 women (preterm = 14, term = 66) by PCR. Overall, 10 women delivered within 14 days of sampling. Predictive capacities of individual biomarkers and cytokine-metabolite combinations for sPTD and delivery within 14 days of sampling were analysed by logistic regression models and area under the receiver operating characteristic curve. Fusobacterium sp., Mubiluncus mulieris and Mycoplasma hominis were detected in more preterm-delivered than term women (P<0.0001), while, M. curtisii was found in more term-delivered than preterm women (P<0.0001). RANTES (0.91, 0.65–1.0), IL-6 (0.79, 0.67–0.88), and Acetate/Glutamate ratio (0.74, 0.61–0.85) were associated with delivery within 14 days of sampling (AUC, 95% CI). There were significant correlations between cytokines and metabolites, and several cytokine-metabolite combinations were associated with sPTD or delivery within 14 days of sampling (e.g. L/D-lactate ratio+Acetate/Glutamate ratio+IL-6: 0.84, 0.67–0.94). Symptomatic women destined to deliver preterm and within 14 days of sampling express significantly higher pro-inflammatory mediators at mid to late gestation. In this cohort, IL-6, Acetate/Glutamate ratio and RANTES were associated with delivery within 14 days of sampling, consistent with their roles in modulating infection-inflammation-associated preterm labour in women presenting with symptoms of preterm birth. Replication of these observations in larger cohorts of women could show potential clinical utility.

Interferon epsilon in the reproductive tract of healthy and genital herpes simplex virus-infected pregnant women: Results of a pilot study

PROBLEM

Recently characterized interferon epsilon (IFNe) protects against sexually transmitted infections, including genital herpes simplex virus (HSV), in animal models. There are no reports of IFNe in genital tract secretions of pregnant women, and data on IFNe in non-pregnant women are limited. This pilot study is the first to measure concentrations of IFNe in vaginal and cervical secretions during pregnancy and compare values between healthy and genital HSV-infected women.

METHOD OF STUDY

Vaginal or cervical specimens from 30 pregnant women were obtained from the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) repository. Cervical samples were collected during the first trimester and vaginal samples across pregnancy. Enzyme-linked immunosorbent assay determined concentrations of IFNe (pg/mL). Data for IFNe were log-transformed and compared by maternal demographics, clinical variables, and HSV status using t tests and linear regression. Repeated measures analysis explored trends across pregnancy.

RESULTS

Among the entire cohort, first trimester concentrations of IFNe in vaginal or cervical secretions decreased as body mass index increased (β = -0.14, P = .0466). Concentrations of vaginal IFNe increased across pregnancy in HSV-infected and healthy women (P = .009). Average vaginal IFNe across pregnancy was lower in women with HSV compared to healthy women (P = .0009).

CONCLUSION

Interferon epsilon increased across pregnancy, but was less abundant in women with HSV. This pilot investigation cannot make any definitive conclusions. However, animal models suggest that IFNe may protect against STIs. Thus, larger studies are required to validate expression of IFNe in the reproductive tract of pregnant women with and without genital infections.

Impact of Pregnancy History and 17-Hydroxyprogesterone Caproate on Cervical Cytokines and Matrix Metalloproteinases

OBJECTIVE

 The objective of this study was to evaluate the impact of pregnancy history and 17-hydroxyprogesterone caproate (17-OHPC) treatment on cervical fluid cytokines and matrix metalloproteinases (MMPs).

STUDY DESIGN

 Cervical fluid was obtained between 16^0/7 and 24^6/7 weeks from women with only prior term births (controls, n = 26), women with one or more prior spontaneous preterm births (SPTBs) choosing to receive 17-OHPC (17-OHPC, n = 24), or to not receive 17-OHPC (refusers, n = 12). Cervical fluid collections were repeated 2, 4, and 8 weeks after the first sample and concentrations of MMPs and cytokines were measured by multiplex immune assay.

RESULTS

 Among women whose earliest prior delivery occurred between 16 and 23 weeks, cervical fluid concentration of interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α at baseline were significantly elevated when compared with cervical cytokines of women whose earliest delivery occurred between 32 and 36 weeks (relative risk ratio was 3.37 for IL-6 [95% confidence interval, CI, 1.08-10.53, p < 0.05], 2.81 for IL-10 [95% CI, 1.39-5.70, p < 0.05], and 6.34 for TNF-α [95% CI, 2.19-18.68, p < 0.001]). Treatment with 17-OHPC had no significant impact on these cytokines.

CONCLUSION

 The cervical fluid of women with a history of an early prior SPTB is characterized by inflammation that is unaffected by 17-OHPC.

Patterns of Systemic and Cervicovaginal Fluid Inflammatory Cytokines throughout Pregnancy

OBJECTIVE

 This study describes the normal variations in serum and cervicovaginal fluid (CVF) cytokine levels throughout pregnancy.

STUDY DESIGN

 This multicenter, prospective study examined trimester-specific maternal serum and CVF cytokines (interleukin [IL]-1α, IL-1β, IL-6, IL-8, IL-10, tumor necrosis factor-α, and C-reactive protein [CRP]). A two-factor linear mixed modeling approach compared cytokine distribution, while pairwise comparisons evaluated differences over time.

RESULTS

 Trimester-specific serum cytokine data were available for 288, 243, and 221 patients, whereas CVF cytokine data were available for 273, 229, and 198 patients. CVF had significantly higher concentrations of IL-1α, IL-1β, IL-6, IL-8, and matrix metalloproteinase-8 (p < 0.001), irrespective of the trimester. At all time points, IL-10 and CRP concentrations were higher in serum than CVF (p < 0.001). Serum IL-10 increased significantly throughout pregnancy (p < 0.001).

CONCLUSION

 Differences in cytokine distribution across different biological fluids are evident throughout pregnancy. These findings provide a framework for examining patterns of changes in cytokines throughout pregnancy.

The role of decidual cells in uterine hemostasis, menstruation, inflammation, adverse pregnancy outcomes and abnormal uterine bleeding

BACKGROUND

Human pregnancy requires robust hemostasis to prevent hemorrhage during extravillous trophoblast (EVT) invasion of the decidualized endometrium, modification of spiral arteries and post-partum processes. However, decidual hemorrhage (abruption) can occur throughout pregnancy from poorly transformed spiral arteries, causing fetal death or spontaneous preterm birth (PTB), or it can promote the aberrant placentation observed in intrauterine growth restriction (IUGR) and pre-eclampsia; all leading causes of perinatal or maternal morbidity and mortality. In non-fertile cycles, the decidua undergoes controlled menstrual bleeding. Abnormal uterine bleeding (AUB) accompanying progestin-only, long-acting, reversible contraception (pLARC) accounts for most discontinuations of these safe and highly effective agents, thereby contributing to unwanted pregnancies and abortion. The aim of this study was to investigate the role of decidual cells in uterine hemostasis, menstruation, inflammation, adverse pregnancy outcomes and abnormal uterine bleeding.

METHODS

We conducted a critical review of the literature arising from PubMed searches up to December 2015, regarding in situ and in vitro expression and regulation of several specific proteins involved in uterine hemostasis in decidua and cycling endometrium. In addition, we discussed clinical and molecular mechanisms associated with pLARC-induced AUB and pregnancy complications with abruptions, chorioamnionitis or pre-eclampsia.

RESULTS

Progestin-induced decidualization of estradiol-primed human endometrial stromal cells (HESCs) increases in vivo and in vitro expression of tissue factor (TF) and type-1 plasminogen activator inhibitor (PAI-1) while inhibiting plasminogen activators (PAs), matrix metalloproteinases (MMPs), and the vasoconstrictor, endothelin-1 (ET-1). These changes in decidual cell-derived regulators of hemostasis, fibrinolysis, extracellular matrix (ECM) turnover, and vascular tone prevent hemorrhage during EVT invasion and vascular remodeling. In non-fertile cycles, progesterone withdrawal reduces TF and PAI-1 while increasing PA, MMPs and ET-1, causing menstrual-associated bleeding, fibrinolysis, ECM degradation and ischemia. First trimester decidual hemorrhage elicits later adverse outcomes including pregnancy loss, pre-eclampsia, abruption, IUGR and PTB. Decidual hemorrhage generates excess thrombin that binds to decidual cell-expressed protease-activated receptors (PARs) to induce chemokines promoting shallow placentation; such bleeding later in pregnancy generates thrombin to down-regulate decidual cell progesterone receptors and up-regulate cytokines and MMPs linked to PTB. Endometria of pLARC users display ischemia-induced excess vasculogenesis and progestin inhibition of spiral artery vascular smooth muscle cell proliferation and migration leading to dilated fragile vessels prone to bleeding. Moreover, aberrant TF-derived thrombin signaling also contributes to the pathogenesis of endometriosis via induction of angiogenesis, inflammation and cell survival.

CONCLUSION

Perivascular decidualized HESCs promote endometrial hemostasis during placentation yet facilitate menstruation through progestational regulation of hemostatic, proteolytic, and vasoactive proteins. Pathological endometrial hemorrhage elicits excess local thrombin generation, which contributes to pLARC associated AUB, endometriosis and adverse pregnancy outcomes through several biochemical mechanisms.

Ancestry informative markers and selected single nucleotide polymorphisms in immunoregulatory genes on preterm labor and preterm premature rupture of membranes: a case control study

Background

A genetic predisposition to Preterm Labor (PTL) and Preterm Premature Rupture of Membranes (PPROM) has been suggested; however the relevance of polymorphisms and ancestry to susceptibility to PTL and PPROM in different populations remains unclear. The aim of this study was to evaluate the contribution of maternal and fetal SNPs in the IL1B, IL6, IL6R, TNFA, TNFR, IL10, TLR2, TLR4, MMP9, TIMP1 and TIMP2 genes and the influence of ancestry background in the susceptibility to PTL or PPROM in Brazilian women.

Methods

Case–control study conducted at a tertiary hospital in São Paulo State, Brazil. We included women with PTL or PPROM and their babies (PTL: 136 women and 88 babies; PPROM: 65 women and 44 babies). Control group included 402 mother-babies pairs of term deliveries. Oral swabs were collected for identification of AIMs by fragment analysis and SNPs by Taqman® SNP Genotyping Assays and PCR. Linkage Disequilibrium and Hardy-Weinberg proportions were evaluated using Genepop 3.4. Haplotypes were inferred using the PHASE algorithm. Allele, genotype and haplotype frequencies were compared by Fisher’s exact test or χ² and Odds Ratio. Logistic regression was performed. Clinical and sociodemographic data were analyzed by Fisher’s exact test and Mann–Whitney.

Results

PTL was associated with European ancestry and smoking while African ancestry was protective. The fetal alleles IL10-592C (rs800872) and IL10-819C (rs1800871) were also associated with PTL and the maternal haplotype TNFA-308G-238A was protective. Maternal presence of IL10-1082G (rs1800896) and TLR2A (rs4696480) alleles increased the risk for PPROM while TNFA-238A (rs361525) was protective. Family history of PTL/PPROM was higher in cases, and time to delivery was influenced by IL1B-31T (rs1143627) and TLR4-299G (rs4986790).

Conclusion

There is an association between European ancestry and smoking and PTL in our Brazilian population sample. The presence of maternal or fetal alleles that modify the inflammatory response increase the susceptibility to PTL and PPROM. The family history of PTL/PPROM reinforces a role for genetic polymorphisms in susceptibility to these outcomes.

Timing of Histologic Progression from Chorio-Deciduitis to Chorio-Deciduo-Amnionitis in the Setting of Preterm Labor and Preterm Premature Rupture of Membranes with Sterile Amniotic Fluid

Background

Histologic chorio-deciduitis and chorio-deciduo-amnionitis (amnionitis) in extra-placental membranes are known to represent the early and advanced stages of ascending intra-uterine infection. However, there are no data in humans about the time required for chorio-deciduitis to develop and for chorio-deciduitis without amnionitis to progress to chorio-deciduitis with amnionitis, and the effect of prolongation of pregnancy on the development of chorio-deciduitis and amnionitis in patients with preterm labor and intact membranes (PTL) and preterm premature rupture of membranes (preterm-PROM). We examined these issues in this study.

Methods

The study population consisted of 289 women who delivered preterm (133 cases with PTL, and 156 cases with preterm-PROM) and who had sterile amniotic fluid (AF) defined as a negative AF culture and the absence of inflammation as evidenced by a matrix metalloproteinase-8 (MMP-8) level <23 ng/ml. We examined the association between amniocentesis-to-delivery interval and inflammatory status in the extra-placental membranes (i.e., inflammation-free extra-placental membranes, choroi-deciduitis only, and chorio-deciduitis with amnionitis) in patients with PTL and preterm-PROM.

Results

Amniocentesis-to-delivery interval was longer in cases of chorio-deciduitis with amnionitis than in cases of chorio-deciduitis only in both PTL (median [interquartile-range (IQR)]; 645.4 [319.5] vs. 113.9 [526.9] hours; P = 0.005) and preterm-PROM (131.3 [135.4] vs. 95.2 [140.5] hours; P<0.05). Amniocentesis-to-delivery interval was an independent predictor of the development of both chorio-deciduitis and amnionitis after correction for confounding variables such as gestational age at delivery in the setting of PTL, but not preterm-PROM.

Conclusions

These data confirm for the first time that, in cases of both PTL and preterm-PROM with sterile AF, more time is required to develop chorio-deciduitis with amnionitis than chorio-deciduitis alone in extra-placental membranes. Moreover, prolongation of pregnancy is an independent predictor of the development of both chorio-deciduitis and amnionitis in cases of PTL with sterile AF.

Prediction of impending preterm delivery based on sonographic cervical length and different cytokine levels in cervicovaginal fluid in preterm labor

AIMS

The aim of this study was to determine whether cervicovaginal interleukin (IL)-1β, IL-6 and IL-8 levels, and cervical length, alone or in combination, could predict impending preterm delivery in women with preterm labor and intact membranes.

MATERIAL AND METHODS

Cervicovaginal swab samples for IL-1β, IL-6, and IL-8 assays were taken from 136 consecutive women with preterm labor (23-34 weeks) before the transvaginal ultrasonography examination to measure cervical length. The primary outcome measurement was spontaneous preterm delivery within 7 days of sampling.

RESULTS

Spontaneous preterm delivery within 7 days occurred in 28.6% (39/136) of patients. Receiver-operator characteristic (ROC) curves indicated that cervical length (P < 0.001), cervicovaginal IL-6 (P < 0.001) and IL-8 (P = 0.014), but not IL-1β, could predict delivery within 7 days. According to the logistic regression analysis, high cervicovaginal IL-8 (P = 0.008) and IL-6 (P = 0.038) levels and short cervical length (P < 0.001) were significantly associated with delivery within 7 days, even after controlling for baseline variables. A combination of cervix length and cervicovaginal IL-8 increased the specificity of detecting delivery within 7 days to 92.8%, which was superior to either test alone (P < 0.001), but the sensitivity was only 56.4%.

CONCLUSION

In women with preterm labor, among the parameters assessed, cervicovaginal IL-6 and IL-8 and cervical length are the most important parameters in predicting impending preterm delivery. A combination of cervix length and cervicovaginal IL-8 appeared to be the best for predicting impending preterm delivery, but the relatively low sensitivity of this test may limit its clinical usefulness.

Bacterial vaginosis in pregnant adolescents: proinflammatory cytokine and bacterial sialidase profile. Cross-sectional study

CONTEXT AND OBJECTIVE

Bacterial vaginosis occurs frequently in pregnancy and increases susceptibility to sexually transmitted infections (STI). Considering that adolescents are disproportionally affected by STI, the aim of this study was to evaluate the cervicovaginal levels of interleukin (IL)-1 beta, IL-6, IL-8 and bacterial sialidase in pregnant adolescents with bacterial vaginosis.

DESIGN AND SETTING

Cross-sectional study at mother and child referral units in Belém, Pará, Brazil.

METHODS

Vaginal samples from 168 pregnant adolescents enrolled were tested for trichomoniasis and candidiasis. Their vaginal microbiota was classified according to the Nugent criteria (1991) as normal, intermediate or bacterial vaginosis. Cervical infection due to Chlamydia trachomatisand Neisseria gonorrhoeae was also assessed. Cytokine and sialidase levels were measured, respectively, using enzyme-linked immunosorbent assays and MUAN conversion in cervicovaginal lavages. Forty-eight adolescents (28.6%) were excluded because they tested positive for some of the infections investigated. The remaining 120 adolescents were grouped according to vaginal flora type: normal (n = 68) or bacterial vaginosis (n = 52). Their cytokine and sialidase levels were compared between the groups using the Mann-Whitney test (P < 0.05).

RESULTS

The pregnant adolescents with bacterial vaginosis had higher levels of IL-1 beta, IL-6 and IL-8 (P < 0.05). Sialidase was solely detected in 35 adolescents (67.2%) with bacterial vaginosis.

CONCLUSIONS

Not only IL-1 beta and sialidase levels, but also IL-6 and IL-8 levels are higher in pregnant adolescents with bacterial vaginosis, thus indicating that this condition elicits a more pronounced inflammatory response in this population, which potentially increases vulnerability to STI acquisition.

Cervicovaginal bacteria are a major modulator of host inflammatory responses in the female genital tract

Colonization by Lactobacillus in the female genital tract is thought to be critical for maintaining genital health. However, little is known about how genital microbiota influence host immune function and modulate disease susceptibility. We studied a cohort of asymptomatic young South African women and found that the majority of participants had genital communities with low Lactobacillus abundance and high ecological diversity. High-diversity communities strongly correlated with genital pro-inflammatory cytokine concentrations in both cross-sectional and longitudinal analyses. Transcriptional profiling suggested that genital antigen-presenting cells sense gram-negative bacterial products in situ via Toll-like receptor 4 signaling, contributing to genital inflammation through activation of the NF-κB signaling pathway and recruitment of lymphocytes by chemokine production. Our study proposes a mechanism by which cervicovaginal microbiota impact genital inflammation and thereby might affect a woman's reproductive health, including her risk of acquiring HIV.

Interleukin 6 and fetal fibronectin as a predictors of preterm delivery in symptomatic patients

Preterm delivery is the leading cause of neonatal mortality and morbidity. The rate of preterm births has been estimated to be about 15 million, which accounts for 11.1% of all live births worldwide. The purpose of this study was to evaluate the cervico-vaginal (CVF) cytokine IL-6 and fetal fibronectin (fFN) status as predictors of preterm delivery in patients with symptoms of preterm labor. Patients with symptoms suggestive of preterm labor were recruited from September 2013 to March 2014. Vaginal swabs were taken for fetal fibronectin test (fFN) and CVF IL-6. Antibiotics, steroids and tocolytics were administered, where appropriate. The outcome was measured by the occurrence of preterm delivery within 14 days from the day of hospital admission. Cut-off value of 1305 pg/mL for the concentration of IL-6 in the CVF was the best predictor of preterm delivery, with the sensitivity of 69.4% and specificity of 68.2%. Patients with positive fFN test had the OR of 6.429 (95%CI 1.991-20.758) to deliver prematurely. The multivariate analysis of combined fFN and CVF IL-6 tests resulted in risk of 86.7% to deliver prematurely, if both tests were positive. The combination of both tests performed better than the individual tests and decreased the false positive rate, which in turn reduced the chances for inappropriate patient treatment, bringing down the costs.

Longitudinal changes in serum proinflammatory markers across pregnancy and postpartum: effects of maternal body mass index

BACKGROUND

The maternal immune system undergoes substantial changes to support healthy pregnancy. Although obesity is a primary driver of inflammation and predictive of perinatal complications, additive effects of pregnancy and obesity on changes in inflammatory processes are not well delineated.

METHODS

This study examined serum proinflammatory markers interleukin(IL)-6, IL-8, tumor necrosis factor (TNF)-α, IL-1β, and C-reactive protein (CRP) during each trimester of pregnancy and 4-6 weeks postpartum among 57 women.

RESULTS

Overall, IL-6 showed an increasing trend across pregnancy and significant increase at postpartum. Similarly, TNF-α increased significantly across gestation, with a further increase at postpartum. Both IL-8 and IL-1β showed a U-shaped curve, decreasing from early to later pregnancy, and increasing at postpartum. Finally, serum CRP decreased significantly across pregnancy, with further decreases at postpartum. Maternal obesity predicted higher IL-6 at each study visit. Obese women showed a trend toward elevated serum CRP during pregnancy, and significantly higher levels at postpartum.

DISCUSSION

The course of pregnancy and postpartum is characterized by significant changes in serum proinflammatory mediators. Obese women show elevations in serum proinflammatory markers relative to normal weight women during pregnancy and postpartum. Further research is needed to determine the extent to which obesity-induced inflammation affects maternal and fetal health.

Inflammation biomarkers in vaginal fluid and preterm delivery

STUDY QUESTION

Which inflammation biomarkers detected in the vaginal fluid are most informative for identifying preterm delivery (PTD) risk?

SUMMARY ANSWER

Elevated interleukin (IL)-6 at mid-trimester was associated with increased odds of spontaneous PTD at <35 weeks and with PTD plus histologic chorioamnionitis (HCA), and had the greatest sensitivity for detecting these two PTD subtypes.

WHAT IS KNOWN ALREADY

Maternal and/or fetal inflammation play a role in some preterm deliveries, therefore inflammation biomarkers might help to identify women at greater risk.

STUDY DESIGN, SIZE, DURATION

We examined 1115 women from the Pregnancy Outcomes and Community Health Study, a cohort study conducted from September 1998 through June 2004, for whom data were available on mid-pregnancy inflammatory biomarkers.

PARTICIPANTS/MATERIALS, SETTING, METHODS

At enrollment at 16-27 weeks gestation, vaginal fluid samples were collected from a swab and 15 eluted biomarkers were measured using the Meso Scale Discovery multiplex electrochemiluminescence platform. Associations of biomarkers with PTD were examined, according to clinical circumstance, week at delivery and presence/absence of HCA. Weighted logistic regression was used to determine odds ratios (OR) and 95% confidence intervals (CI) adjusted for race. Sensitivity and specificity were compared between individual and multiple biomarkers, identified by a bootstrapping method.

MAIN RESULTS AND THE ROLE OF CHANCE

Elevated IL-6 (>75th percentile) displayed the strongest association with spontaneous PTD <35 weeks (OR 2.3; CI 1.3-4.0) and PTD with HCA (OR 2.8; CI 1.4-6.0). The sensitivity of IL-6 to detect spontaneous PTD <35 weeks or PTD with HCA was 0.43 and 0.51, respectively, while specificity was 0.74 and 0.75, respectively. IL-6 plus IL1β, IL-6r, tumor necrosis factor-alpha or granulocyte-macrophage colony-stimulating factor increased specificity (range 0.84-0.88), but decreased sensitivity (range 0.28-0.34) to detect both PTD subtypes. Results were similar when a combination of IL-6 and bacterial vaginosis (BV) was explored. Thus, the use of multiple biomarkers did not detect PTD subtypes with a greater sensitivity than IL-6 alone, and IL-6 is a specific but non-sensitive marker for the detection of spontaneous PTD.

LIMITATIONS, REASONS FOR CAUTION

Our ability to find small effect size associations between PTD and inflammation biomarkers (OR <2.0) might have been limited by the modest number of less common PTD subtypes in our population (e.g. spontaneous delivery <35 weeks, PTD accompanied by HCA) and by relatively higher variability for some cytokines, for example tumor necrosis factor-α, IL-12p70, IL-10 and granulocyte-macrophage colony-stimulating factor, that are less stable and commonly undetectable or detectable at low levels in human vaginal secretions.

WIDER IMPLICATIONS OF THE FINDINGS

Larger studies are needed to further explore a role of inflammation biomarkers in combination with other risk factors, including specific BV-associated organisms, for the prediction of PTD subtypes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Institute of Child Health and Human Development, National Institute of Nursing, March of Dimes Foundation, Thrasher Research Foundation and Centers for Disease Control and Prevention. The authors have no conflicts of interest.

Biochemical markers predictive of preterm delivery

Preterm delivery is the leading cause of perinatal morbidity and mortality worldwide. Despite a great deal of research into this disease, we still do not understand its pathophysiology. Our treatments for this disease are only marginally effective. Biochemical markers were developed with the hope of giving us new tools to prevent preterm deliveries. Specifically the hope was that they could predict which patients were destined to have a preterm delivery. At the present time these markers perform only satisfactorily at predicting preterm labor. They are expensive and not convenient to use at present. Perhaps more importantly, though, these markers have given us insight into the complexities of preterm delivery. Preterm delivery can arise from many different etiologies. This will lead to research into new treatments as knowledge about preterm delivery is amassed. We know that any number of pathological processes may be involved in any given patient with preterm labor. Biochemical markers have the distinct advantage of being able to determine the specific pathophysiology in a given patient and may allow us to tailor therapy according to the specific problem. In the future it is likely that a careful search for specific pathophysiology will be the only way we can treat this disease effectively. For the present time the biochemical markers will be used only to predict preterm delivery. Ultrasound measurements of the cervix during the pregnancy are likely a faster and less expensive way to accomplish that goal.

Pathogenesis to treatment: preventing preterm birth mediated by infection

Prevention of preterm birth and subsequent newborn immaturity is a primary goal of obstetrical care worldwide. Accumulated evidence shows that 1) as many as 25–50% of preterm births are caused by common genital tract infections and subsequent maternal/fetal inflammatory responses; 2) microbial and maternal host factors (phospholipases, proteases, etc.) play roles in preterm labor and preterm premature rupture of membranes (pPROM); 3) integrated aspects of maternal and fetal host responses (inflammation, altered immune adaptations, endocrine and paracrine mechanisms) play increasingly understood roles in premature activation of parturition; and 4) identification and systemic treatment of common genitourinary infections, most importantly bacterial vaginosis (BV), reduce the risks of preterm delivery and PROM.

Novel biomarkers for the prediction of the spontaneous preterm birth phenotype: a systematic review and meta-analysis

BACKGROUND

Being able to predict preterm birth is important, as it may allow a high-risk population to be selected for future interventional studies and help in understanding the pathways that lead to preterm birth.

OBJECTIVE

To investigate the accuracy of novel biomarkers to predict spontaneous preterm birth in women with singleton pregnancies and no symptoms of preterm labour.

SEARCH STRATEGY

Electronic searches in PubMed, Embase, Cinahl, Lilacs, and Medion, references of retrieved articles, and conference proceedings. No language restrictions were applied.

SELECTION CRITERIA

Observational studies that evaluated the accuracy of biomarkers proposed in the last decade to predict spontaneous preterm birth in asymptomatic women. We excluded studies in which biomarkers were evaluated in women with preterm labour.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data on study characteristics, quality, and accuracy. Data were arranged in 2 × 2 contingency tables and synthesised separately for spontaneous preterm birth before 32, 34, and 37 weeks of gestation. We used bivariate meta-analysis to estimate pooled sensitivities and specificities, and calculated likelihood ratios (LRs).

MAIN RESULTS

A total of 72 studies, including 89,786 women and evaluating 30 novel biomarkers, met the inclusion criteria. Only three biomarkers (proteome profile and prolactin in cervicovaginal fluid, and matrix metalloproteinase-8 in amniotic fluid) had positive LRs > 10. However, each of these biomarkers was evaluated in only one small study. Four biomarkers had a moderate predictive accuracy (interleukin-6 and angiogenin, in amniotic fluid; human chorionic gonadotrophin and phosphorylated insulin-like growth factor binding protein-1, in cervicovaginal fluid). The remaining biomarkers had low predictive accuracies.

CONCLUSIONS

None of the biomarkers evaluated in this review meet the criteria to be considered a clinically useful test to predict spontaneous preterm birth. Further large, prospective cohort studies are needed to evaluate promising biomarkers such as a proteome profile in cervicovaginal fluid.

Cervical interleukin-6 as a predictive test for preterm delivery in symptomatic women: preliminary results

OBJECTIVE

The aim of this study is to assess the efficacy of cervical interleukin-6 (IL-6) compared with cervical length and its association in the prediction of preterm delivery in symptomatic women.

STUDY DESIGN

Observational prospective study was performed at Hospital Universitario La Fe, Valencia (Spain).

SAMPLE

100 women between 24 and 34 weeks gestational age, with threatened preterm delivery and intact membranes during the period 2006-2008.

METHODS

Transvaginal scan to assess cervical length was performed and cervical swab for IL-6 detection was taken. Statistical analysis included Chi-square test, receiver operating characteristic (ROC) curve analysis, COX regression, logistic regression, and Kaplan-Meier survival analysis.

RESULTS

The prevalence of preterm delivery at <37 weeks was 35% and at <32 weeks was 5%. Cervical length was <15 mm in 12% and <30 mm in 62% of the cases. Cervical length and IL-6 were useful for prediction of delivery at 48 h, 7 days, <32, and <34 weeks. Using ROC curves, the IL-6 value that showed best accuracy for prediction of preterm delivery was >210 pg/ml. No differences were observed between the area under the curve (AUC) of IL-6 and cervical length for the prediction of preterm delivery. The association of IL-6 (>210 pg/ml) and cervical length (<30 mm) increases the prediction of either alone.

CONCLUSIONS

Cervical IL-6 can predict preterm delivery similarly to cervical length; when combined, it adds prognostic information to that provided by sonographic measurement of the cervical length.

Regulation of interleukin-6 expression in human decidual cells and its potential role in chorioamnionitis

Chorioamnionitis frequently precedes both genital tract and placental inflammation and is both a primary cause of maternal morbidity and a major antecedent of preterm premature rupture of the membranes (PPROM) as well as preterm delivery (PTD). In most cases of chorioamnionitis, neutrophils dominate the decidua. In a subset of these cases, a predominance of monocytes is uniquely associated with both neonatal intraventricular hemorrhage and death. The multifunctional cytokine, interleukin-6, promotes local monocyte dominance via several mechanisms. In this study, immunostaining of placental sections revealed significantly higher interleukin-6 HSCOREs in decidual cells (DCs) but not in interstitial trophoblasts, in chorioamnionitis versus gestational age-matched control placentas (P < 0.05). In confluent leukocyte-free term DCs, secreted interleukin-6 levels in incubations with estradiol-17β were increased 2500-fold by IL-1β (P < 0.05). This up-regulation was inhibited by more than 50% in parallel incubations that included medroxyprogesterone acetate (n = 12, P < 0.05). Western blotting data confirmed these enzyme-linked immunosorbent assay results; quantitative RT-PCR findings demonstrated corresponding changes in interleukin-6 mRNA levels. Specific inhibitors of signaling for both nuclear factor-κB activation and p38-mitogen-activated protein kinase, but not for protein kinase C, significantly decreased IL-1β-enhanced interleukin-6 expression levels in cultured DCs. In conclusion, in situ and in vitro results indicate that significantly enhanced interleukin-6 expression levels in DCs during chorioamnionitis could be pivotal in skewing decidual monocyte differentiation to macrophages.

Inflammatory cytokines and spontaneous preterm birth in asymptomatic women: a systematic review

OBJECTIVE

To estimate the association between inflammatory cytokines and the risk of spontaneous preterm birth in asymptomatic women.

DATA SOURCES

We searched electronic databases of the human literature in PubMed, EMBASE, and the Cochrane Library up to February 2010 using the following key words: "preterm/pre-term + (birth/delivery)" and "cytokine" or "inflammation/inflammatory + marker/biomarker."

METHODS OF STUDY SELECTION

We included observational studies that reported the association between common inflammatory cytokines and spontaneous preterm birth as an outcome in asymptomatic women. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using fixed and random effects models.

TABULATION, INTEGRATION, AND RESULTS

Seventeen primary studies comprising 6,270 participants met the inclusion criteria. Spontaneous preterm birth was strongly associated with increased levels of interleukin-6 (IL-6) in midtrimester cervicovaginal fluid (OR 3.05, 95% CI 2.00-4.67) (number needed to treat=7 for identifying an additional preterm delivery) and amniotic fluid (OR 4.52, 95% CI 2.67-7.65) (number needed to treat=7), but there was no association in plasma specimen (OR 1.5, 95% CI 0.7-3.0). Spontaneous preterm birth was strongly associated with increased C-reactive protein (CRP) levels in midtrimester amniotic fluid (OR 7.85, 95% CI 3.88-15.87) (number needed to treat=3), but the association was weak in plasma specimen (OR 1.53, 95% CI 1.22-1.90). There were insufficient data (fewer than three studies) for meta-analysis in other inflammatory cytokines.

CONCLUSION

Inflammatory cytokine IL-6 in cervicovaginal fluid and IL-6 and CRP in amniotic fluid but not in plasma are strongly associated with spontaneous preterm birth in asymptomatic women, suggesting that inflammation at the maternal-fetal interface, rather than systemic inflammation, may play a major role in the etiology of such spontaneous preterm births.

Mid-trimester cervical inflammatory milieu and sonographic cervical length

OBJECTIVE

The purpose of this study was to explore the relation between the relative balance of pro- and antiinflammatory cytokines in cervical fluid and mid-trimester cervical length.

STUDY DESIGN

In this prospective longitudinal cohort of women with a previous spontaneous preterm birth, mid-trimester cervical length ultrasound scans and cervical fluid levels were obtained serially. Multiple pro- and antiinflammatory cytokines were selected. We summed the multiples of the median for proinflammatory cytokines to generate the proinflammatory and the antiinflammatory scores. The relation between cervical length and pro-/antiinflammatory ratio was assessed by generalized estimating equations.

RESULTS

The pro-/antiinflammatory ratio had a negative linear association with cervical length (beta = -0.09; P < .001). Sixty percent of visits demonstrated greater concentrations of proinflammatory cytokines relative to antiinflammatory cytokines. This relationship did not change between first and last visits.

CONCLUSION

Among women with a previous preterm birth, shorter mid-trimester cervical length is associated with a more proinflammatory balance of cytokines in the cervical inflammatory milieu.

Integrated review of cytokines in maternal, cord, and newborn blood: part I--associations with preterm birth

Preterm birth (PTB; spontaneous delivery prior to 37 weeks gestation) affects one out of eight infants born in the United States and is the most common cause of neonatal morbidity and mortality. Although the pathogenesis of PTB is multifactorial, a growing body of literature supports the hypothesis that one cause of PTB is inflammation in pregnancy. Investigators have implicated mediators of inflammation, most notably proinflammatory cytokines, as being associated with and perhaps a playing a causal role in the pathogenesis of preterm labor and adverse early fetal outcomes. Though researchers have pursued the association of cytokines with preterm labor and subsequent early adverse fetal outcomes as a line of research, there has been little integration of diverse findings across studies. This systematic review appraises the empirical evidence from human studies for the association of levels of cytokines in blood with preterm labor and adverse early fetal outcome to examine the current state of the science in this important area of biobehavioral research. The most consistent finding is that increased levels of proinflammatory cytokines, particularly interleukin (IL) 6, IL-beta1, and tumor necrosis factor alpha (TNF-alpha), are associated with PTB as compared to levels found at term birth. However, there have been relatively few studies and results have not been consistent. Therefore, further research is needed to elucidate the association of these inflammatory mediators with adverse pregnancy outcomes.

Efficacy of an acidic vaginal gel on vaginal pH and interleukin-6 levels in low-risk pregnant women: a double-blind, randomized placebo-controlled trial

BACKGROUND

Increased interleukin-6 (IL-6) levels and a vaginal pH of > 4.7 are associated with obstetric complications such as preterm delivery and low birth weight. Topical treatments, able to maintain a physiological vaginal pH, could help in the prevention of vaginal infections.

STUDY AIM

In a randomized, double-blind, placebo-controlled trial, we evaluated the effects of an acidic buffering vaginal gel (Miphil) on vaginal pH and IL-6 levels in pregnant women.

PATIENTS AND METHODS

Seventy low-risk women pregnant with a singleton (second trimester) were enrolled in the trial. Thirty-five were randomized to the acidic gel, 2.5 g every 3 days for 12 weeks, and 35 to the corresponding placebo. Vaginal pH and vaginal IL-6 level were measured at baseline and after 12 weeks. Women were then followed until delivery. The main outcome measures were vaginal pH, vaginal pH normalization (pH < 4.5) and vaginal IL-6 levels.

RESULTS

Vaginal pH at baseline was 4.6 +/- 0.4 and 4.4 +/- 0.3 in the acidic gel and the placebo group, respectively. At baseline, a total of 40% (14/35) and 22% (8/35) of women in each group, respectively, had a vaginal pH of > or = 4.7. At week 12, the vaginal pH was 4.3 +/- 0.3 in the acidic gel group and 4.3 +/- 0.3 in the placebo group (NS). The acidic gel normalized the vaginal pH in ten out of 14 women (p = 0.04) in comparison with only one out of eight women in the placebo group (NS). The acidic gel induced a significant (p < 0.02) reduction of vaginal IL-6 from 12.0 +/- 7 to 8.9 +/- 5 pg/l (-36%). In the placebo group, IL-6 increased from 9.0 +/- 5 to 13.5 +/- 6.8 pg/l (+50%) (p = 0.05). Birth weight was 2978 +/- 700 g in the placebo group and 3241 +/- 477 g in the acidic gel group (p = 0.06).

CONCLUSIONS

The use of the acidic gel in low-risk pregnant women is able to maintain a physiological vaginal ecosystem and prevents the increases of vaginal pH and vaginal IL-6. Prospective and controlled trials are warranted to evaluate whether this acidic gel can reduce obstetric complications linked to vaginal inflammation during pregnancy.

Insulin-like growth factor-binding protein-1 (IGFBP-1) in cervical secretions as a predictor of preterm delivery

OBJECTIVE

The objective of this study was to investigate the level of insulin-like growth factor-binding protein-1 (IGFBP-1) in cervical secretions and Bishop score as predictors of preterm delivery in asymptomatic pregnant women.

METHODS

This was a prospective study at the Clinic for Gynecology and Obstetrics at the University Clinical Center in Tuzla, on a sample of 80 healthy pregnant women at between 24 and 34 gestational weeks. After interview every woman underwent IGFBP-1 concentration measurement by the 'Actim Partus' test. The Bishop score was determined by the author (A.L) during vaginal examination. Rates among groups were compared using arithmetic mean and standard deviation, Student's t-test, Mann-Witney U-test, and Spearman-Rank correlation test. Statistical importance was determined at the variation levels of 5% and 1%.

RESULTS

Eight (10.00%) women in the study group had a positive Actim Partus test and six (7.50%) of them had a preterm delivery. The positive predictive value was 44.44% and negative predictive value was 98.59%. The specificity of the Bishop score in the study group was 83.78% and the sensitivity was 50.00%. The positive predictive value of the Bishop score in this group was 20.00% and the negative predictive value was 95.36%. There was no correlation between the Bishop score and Actim Partus test (p = 0.15).

CONCLUSIONS

If the concentration of IGFBP-1 is <10 microg/L (negative Actim Partus test) in asymptomatic pregnant women, the risk of preterm delivery is low. The Actim Partus test could be used as a screening test for preterm delivery in asymptomatic pregnant women.

Cervical and vaginal cytokine determinations in pregnant women: methodologic issues

Investigations of the role cytokines play in preterm birth are complicated by a number of methodologic issues that arise as to the most feasible and efficient methods to measure cytokines. The purpose of this article is to review methodologic issues surrounding the measurement of vaginal and cervical cytokines, specifically IL-1beta, IL-6, and TNF-alpha, in pregnant women experiencing preterm labor. Specifically, two quantification methods, weight and protein assay, and cytokine specimens from two different sites, vaginal and cervical, were compared. There were no significant correlations between cytokine levels using the protein versus weight quantification method. The weight method had more negative values and thus the protein quantification method was more accurate. There were high correlations between cervical and vaginal IL-1beta levels and IL-6 levels, but cervical and vaginal TNF-alpha levels were not correlated.

Expression of cytokines and chemokines in cervical and amniotic fluid: relationship to histological chorioamnionitis

OBJECTIVE

To correlate cervical and amniotic fluid cytokines and macrophage-related chemokines to the development of histological chorioamnionitis (HCA) in patients with preterm labor (PTL) and preterm prelabor rupture of the membranes (PPROM).

STUDY DESIGN

Cervical and amniotic fluid interleukin (IL)-6, IL-8, IL-18, monocyte chemotactic protein (MCP)-1, MCP-2, and MCP-3 from pregnant women (at <or=34 weeks of gestation) in PTL (N = 42) were analyzed and related to the subsequent occurrence of HCA or inflammatory signs in the placenta. For the patients with PPROM (N = 30) only amniotic fluid proteins were analyzed.

RESULTS

Intra-amniotic levels of IL-6, IL-8, IL-18, MCP-1, and MCP-3 were significantly higher in PTL cases with HCA compared to non-HCA controls, whereas no such relationship was obtained in the PPROM group. Cervical IL-8 and IL-6 (but not IL-18, MCP-1, MCP-2, and MCP-3) in PTL patients was associated with HCA, and at a cut-off level of 10.0 ng/mL cervical IL-8 was a strong predictor of HCA in the PTL cases (sensitivity 100%, specificity 67%, positive predictive value 63%, negative predictive value 100%). The cytokine and chemokine levels in the group with inflammatory signs were generally higher than in controls but lower compared to the concentrations in the HCA group.

CONCLUSIONS

The amniotic levels of IL-6, IL-8, IL-18, and the CC-chemokines MCP-1 and MCP-3 in PTL patients all predicted HCA, whereas only IL-8 was a clinically useful marker of HCA in the cervical fluid. In addition there is indication that the levels of inflammatory proteins are related to the degree of inflammatory infiltration in placental tissue samples.

Uterine Cervical Inflammatory Cytokines, Interleukin-6 and -8, as Predictors of Miscarriage in Recurrent Cases

PROBLEM

Inflammatory changes frequently occur in cases of second trimester miscarriage or pre-term delivery, but little attention has been paid to this association with recurrent miscarriage. As interleukin-6 and interleukin-8 are inflammatory cytokines reported to be associated with bacterial vaginosis, intrauterine infections, and pre-term delivery, we here investigated whether they might have predictive value for spontaneous abortion in recurrent cases.

METHOD OF STUDY

Cervical mucus and sera were collected at 4-5 weeks' gestation from a total of 59 patients with a history of two or more unexplained consecutive first trimester miscarriages, and examined by enzyme-linked immunosorbent assay. Patients then were followed up without medication and their pregnancy outcomes were compared with the test results.

RESULTS

Of a total of 59 patients, 13 (22%) miscarried subsequently. Both IL-6 and IL-8 in cervical mucus were significantly higher in patients who miscarried subsequently than in those who had a live birth. In addition, there was no correlation between cervical mucus and serum concentrations of IL-6 and IL-8 take at the same time, and there was no relation with serum IL-6 and IL-8 levels between the two groups.

CONCLUSION

Cervical IL-6 and IL-8 might have predictive value for cases of recurrent miscarriage.

Redirection of cytokine production by lymphocytes from women with pre-term delivery by dydrogesterone

PROBLEM

To study the ability of dydrogesterone to modulate the production of pro-inflammatory and anti-inflammatory cytokines by lymphocytes from women undergoing pre-term delivery (PTD).

METHOD OF STUDY

Peripheral blood mononuclear cells (PBMC) from 18 subjects undergoing PTD were stimulated with the mitogen phytohemagglutinin in the presence and absence of progesterone and dydrogesterone. The levels of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-10 in culture supernatants were then estimated by enzyme-linked immunoabsorbant assay. Cytokine production in the presence and absence of progesterone and dydrogesterone were compared.

RESULTS

The exposure of PBMC to dydrogesterone resulted in a significant inhibition in the production of the pro-inflammatory cytokines IFN-gamma and TNF-alpha and a significant increase in the levels of the anti-inflammatory cytokine IL-4, resulting in a substantial shift in the ratio of Th1/Th2 cytokines.

CONCLUSION

Dydrogesterone induces a shift in cytokine bias, by inhibiting pro-inflammatory cytokine production and increasing anti-inflammatory cytokine production.

Diagnostic Accuracy of Cervicovaginal Interleukin-6 and Interleukin-6:Albumin Ratio as Markers of Preterm Delivery

Background: Absence of fetal fibronectin (fFN) in the cervicovaginal fluid (CVF) of women with symptoms of preterm labor is an excellent predictor of women who will not deliver within 2 weeks of testing. Preliminary studies suggest interleukin (IL)-6 performs similarly to fFN. The positive predictive values of both these assays are poor. Inconsistent specimen collection may explain this poor performance. The objective of this study was to validate the clinical utility of cervicovaginal IL-6 and investigate the utility of the IL-6:albumin ratio to predict delivery within 14 days.

Methods: We quantified albumin and IL-6 with the DPC Immulite® in 660 CVF specimens collected for physician-ordered fFN analysis. The clinical utility of IL-6 and IL-6:albumin to predict delivery within 14 days of collection was determined.

Results: The sensitivity, specificity, and positive and negative likelihood ratios for delivery within 14 days were 65%, 87%, 4.8, and 0.4, respectively, for fFN and 35%, 91%, 3.8, and 0.7 for IL-6, with a 250 ng/L cutoff. With a preterm delivery prevalence of 4.7%, positive and negative predictive values were 19% and 98%, respectively, for fFN and 16% and 97% for IL-6. The areas under the ROC curves were 0.71 and 0.51 for IL-6 and IL-6:albumin, respectively. Odds ratios for delivery within 14 days of collection were 11.8 (P &lt;0.0001), 5.5 (P = 0.0001), and 2.4 (P = 0.06) for fFN, IL-6, and IL-6:albumin, respectively.

Conclusions: Cervicovaginal IL-6 may have utility for predicting preterm labor while offering the potential for substantial cost savings. Assay performance characteristics are not improved by normalizing IL-6 to albumin.

Cervical length changes during preterm cervical ripening: effects of 17-alpha-hydroxyprogesterone caproate

OBJECTIVE

The purpose of this study was to evaluate whether 17-alpha-hydroxyprogesterone caproate (17P) treatment affect changes in cervical length.

STUDY DESIGN

Women with singleton pregnancy, between 25 and 33 + 6 weeks of gestation, who were hospitalized for preterm labor were included. Patients with rupture of membranes and/or signs of chorioamnionitis were excluded. Sixty undelivered patients were allocated randomly to either observation or to receive 341 mg of 17P intramuscularly, twice each week until gestational week 36. Cervical length was measured by transvaginal ultrasound scanning at discharge and at day 7 and 21 after discharge. Statistical comparisons were done with analysis of variance and chi-square test.

RESULTS

Shortening of the cervix in the observation group (30 cases) was higher than in the 17P group (30 cases) both at day 7 (2.37 +/- 2.0 mm vs 0.83 +/- 1.74 mm; P = .002) and day 21 (4.60 +/- 2.73 mm vs 2.40 +/- 2.46 mm; P = .002). Treatment with 17P was associated with both a reduction in the risk of cervical shortening of > or = 4 mm (odds ratio, 0.18; 95% CI, 0.04-0.66) and in the risk of preterm delivery (odds ratio, 0.15; 95% CI, 0.04-0.58).

CONCLUSION

Undelivered patients after preterm labor undergo progressive shortening of the cervix, which is attenuated by 17P treatment.

Comparison of Vaginal Cytokine Collection Methods

OBJECTIVE

The objective of our study was to correlate the interleukin-6 (IL-6) concentrations detected in patient-collected specimens with provider-collected specimens and compare the reproducibility of the methods.

STUDY DESIGN

All enrolled participants underwent pelvic examination with collection of cytokine samples by the provider and also collected samples themselves using vaginal swabs. The order of sample collection was randomly assigned. All samples were frozen at -80 degrees C for batch analysis. A commercial enzyme-linked immunosorbent assay was used to determine the concentrations of IL-6 in all samples.

RESULTS

IL-6 concentrations from wicks and swabs were correlated in a linear fashion (r = 0.67, P < 0.001). IL-6 concentrations in the two swabs (r = 0.94, P < 0.001) and the two wicks (r = 0.71, P < 0.001) were correlated in a linear fashion, although there was more variability in wick specimens.

CONCLUSION

IL-6 concentrations can be reproducibly measured using either method. The ease of patient swab collection and the correlation with provider-collected specimens may make frequent assessment of the vaginal cytokine environment more acceptable to patients.

Detection of interleukin 6 mRNA by RT-PCR in vaginal secretions: association with preterm delivery and neonatal infection in women with preterm labour and intact membranes

OBJECTIVE

To find a biological marker associated with preterm delivery or neonatal infection in pregnant women with preterm labour and intact membranes.

STUDY DESIGN

Cervical secretions were collected from 286 women hospitalized for preterm labour with intact membranes at 24-34 weeks' gestation. The outcomes studied were delivery before 33 and 35 weeks' gestation, chorioamnionitis, and neonatal infection, and their association with the presence of IL-6 mRNA in cervical secretions as detected by RT-PCR. The other infectious markers tested were: bacterial vaginosis and fetal fibronectin in cervical secretions; serum CRP and white blood cell count.

RESULTS

The vaginal secretions of 13 of 286 women (4.7%) contained IL-6 mRNA. The only other marker tested significantly associated with IL-6 mRNA+ was the presence of streptococcus in vaginal secretions (30.8% versus 9.4% in the IL-6+ and-groups, p = 0.03). Although the difference did not reach statistical significance (p<0.06 and 0.08, respectively), in women with IL-6 mRNA in cervical secretions we observed a tendency to give birth before 33 and 35 weeks more often than the population as a whole. This group was at higher risk of neonatal infection (38.5% versus 15.1%; p = 0.04). After adjustment for infectious risk factors, IL-6 remained significantly associated with neonatal infection (OR = 4.6, 95% CI [1.1-18.9]). The sensitivity of IL-6 mRNA for neonatal infection was 11.1%. The specificity was 96.7%.

CONCLUSION

The detection of IL-6 mRNA by RT-PCR in vaginal secretions allows identification of a small group of women at high risk of neonatal infection, independently of other markers of infection.

Decreased Proinflammatory Cytokines in Cervicovaginal Fluid, as Measured in Midgestation, are Associated with Preterm Delivery

PROBLEM

The main aim of this study was to investigate the relationship between selected proinflammatory cytokines [interleukin IL-1 alpha (IL-1alpha), IL-1 beta (IL-1beta), IL-6 and IL-8] concentrations in cervicovaginal fluid, as measured in midgestation, and the risk of subsequent preterm delivery.

METHOD OF STUDY

Cervicovaginal fluids were obtained from a cohort of 114 pregnant women at 22-34 weeks' gestation and analyzed for the concentrations of IL-1alpha, IL-1beta, IL-6 and IL-8 using enzyme-linked immunosorbent assay technique. Lower genital tract microbiology was diagnosed using Gram stain method and by culture.

RESULTS

Mean gestational age at the time of sampling was 29.0 weeks. Mean time between sampling and delivery was 9.3 weeks (S.D. 4.7). Median cervicovaginal concentrations of IL-1alpha, IL-1beta, IL-6 and IL-8 did not differ between preterm and term delivery group. Women with lower genital tract pathological flora and IL-1alpha concentration below 25th percentile presented significant risk of subsequent preterm delivery as compared with women with no low cytokines (OR = 10.7; 95% CI, 2.0-58.1). Women with more than one cytokine' low concentration (below 25th percentile) presented an increased risk of preterm delivery--OR = 11.8 (95% CI, 1.8-78.0).

CONCLUSIONS

The midgestation cytokines' measurement in cervicovaginal fluid of pregnant women could be useful for prediction of preterm delivery only among women with lower genital tract pathological flora.

The interleukin-6--174 single nucleotide polymorphism: cervical protein production and the risk of preterm delivery

OBJECTIVE

The purpose of this study was to determine the associations between preterm delivery (PTD), cervical fluid interleukin-6 (IL-6) concentration, and the single nucleotide polymorphism at position -174 in the IL-6 gene.

STUDY DESIGN

Cervical fluid samples were obtained from women 23 to 32 weeks' gestation with symptoms of preterm labor. Concentrations of IL-6 were determined by enzyme-linked immunosorbent assay (ELISA). IL-6 genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

RESULTS

One hundred thirty-seven women were enrolled, and complete information was available for 126. Cervical fluid IL-6 concentrations were not elevated in women destined to have a spontaneous PTD ( P = .86). IL-6 -174 genotype was not associated with PTD ( P = .62) or cervical fluid IL-6 concentration ( P = .36). Neonatal IL-6-174 genotype was not associated with PTD or IL-6 concentration.

CONCLUSION

Cervical fluid concentrations of IL-6 were not elevated in symptomatic women destined to have a spontaneous PTD. The presence of maternal IL-6 -174C was not associated with cervical fluid concentration of IL-6 or risk of PTD.

A review of the role of proinflammatory cytokines in labor and noninfectious preterm labor

The prevention of preterm labor has the potential to reduce newborn morbidity and mortality by decreasing the incidence of preterm birth. Half of all preterm births occur in women with no known clinical risk factors. Labor onset and progress is multifactorial, and we are just beginning to understand the role of cytokines in uterine activity. The purpose of this article is to review the role of cytokines in labor and preterm labor not associated with infection and to provide implications for research and practice.

Changes in the cervical competence in preterm labour

Cervical competence is a key function in normal and abnormal labour. Remodelling of the cervical structure, by reorientation and changes in the integrity of collagen fibres by an alteration in the content of water, proteoglycans and hyaluronic acid, takes place before parturition. Such morphological changes have been associated with the activation of several biochemical pathways, sharing those of an apyretic, proinflammatory reaction, including the inducible isoform of the nitric oxide synthase (NOS). Nitric oxide (NO) is believed to be the final mediator in the mechanisms that allow ripening of the cervix. A reduction of NO activity in the uterus, together with its activation in the cervix, is hypothesised to be a facilitating factor in human parturition. The local application of NO donors in both animals and humans induces ultrastructural changes similar to those occurring during physiological cervical maturation. NO donors have proven to be clinically effective in facilitating first trimester dilation and curettage. Preliminary data also suggest that in women presenting with threatening preterm labour, there is increased activity of NO in the cervix, which is associated with shortening. A complex interaction between cytokines, prostaglandins (PGs) and NO is the key biochemical pathway accounting for the preterm ripening of the cervix.

Secondary predictors of preterm labour

In addition to primary predictors of preterm birth which are used to estimate the baseline risk of preterm birth, secondary predictors (based on examinations done during the current pregnancy) allow a more accurate assessment of the risk of preterm birth in individual women. Screening for early signs of spontaneous preterm labour has always been an important topic in obstetric care. During the last two decades, the detection of fetal fibronectin (FFN) from cervicovaginal secretions and cervical shortening diagnosed by transvaginal ultrasonography have emerged as the major secondary predictors of preterm birth. Both markers have been extensively studied and consistently shown to be strong short term predictors of preterm birth across a wide range of gestational ages. Other secondary predictors that confirm the role of intrauterine infection in the pathogenesis of preterm birth are bacterial vaginosis (BV) and elevated levels of interleukin (IL)-6, IL-8, ferritin and granulocyte colony-stimulating factor. Apart from BV, inflammatory markers are still not routinely used. The sensitivity of single markers in predicting preterm birth is only moderate and serial examinations of markers, combinations of different markers and multiple marker tests have been studied, with limited results. Studies of interventions in order to prevent preterm birth have also yielded mixed benefits, as a consequence of which the use of these markers to screen low risk pregnancies is generally not recommended. Currently, secondary predictors of preterm birth are used mainly to design new intervention studies tailored to specific high risk populations and to avoid unnecessary interventions in the management of high risk women.

Relationship between cervical mucus interleukin-8 concentrations and vaginal bacteria in pregnancy

PROBLEM

High interleukin (IL)-8 concentration in cervical mucus in the second trimester is a risk factor for premature birth. We investigated the relationship between vaginal pathogens and IL-8 in cervical mucus.

METHOD OF STUDY

In 501 women with single pregnancy, vaginal secretions were cultured for bacteria and cervical mucus IL-8 concentrations were measured between 20 and 24 gestational weeks.

RESULTS

Lactobacillus species were detected in 56.0% of 84 subjects with high IL-8 (> or =377 ng/mL), significantly less often than in 417 subjects with IL-8 below 377 ng/mL (84.7%; P < 0.0001). Anaerobic pathogens were detected in 83.3% of high IL-8 subjects, significantly more often than in normal IL-8 subjects (43.9%; P < 0.0001). By multivariate analysis, cervical IL-8 was significantly high only in subjects without Lactobacillus species; they showed a significantly higher prematurity rate than Lactobacillus-positive subjects.

CONCLUSIONS

Absence of vaginal Lactobacilli was associated with increased cervical IL-8 and increased risk of premature delivery.

Detection of interleukin-6 in vaginal secretions of women with preterm premature rupture of membranes and its association with neonatal infection: a rapid immunochromatographic test

OBJECTIVE

The purpose of this study was to evaluate the diagnostic value of an interleukin-6 (IL-6) bedside test of vaginal secretions for neonatal infection in cases of preterm premature rupture of membranes.

STUDY DESIGN

This prospective clinical study included 73 patients. Interleukin-6 protein in vaginal secretions was determined with an immunochromatographic bedside test in <20 minutes.

RESULTS

Elevated C-reactive protein level (>20 mg/dL; odds ratio, 5.1; 95% CI, 0.9-28.6) and positive interleukin-6 level (odds ratio, 4.6; 95% CI, 1.2-18.4) were both associated with neonatal infection. After adjustment, only interleukin-6 remained associated with neonatal infection (odds ratio, 4.5; 95% CI, 1.1-18.5). The sensitivity of interleukin-6 for the prediction of neonatal infection was 79% (95% CI, 65-92); its specificity was 56% (95% CI, 42-70); its positive predictive value was 30% (95% CI, 12-47), and its negative predictive value was 92% (95% CI, 84-99).

CONCLUSION

Interleukin-6 protein determination by this new immunochromatographic test is a noninvasive prenatal vaginal marker of neonatal infection.

Procalcitonin in cervicovaginal secretion in pregnancies complicated by preterm labor--a preliminary report

OBJECTIVES

Although the usefulness of procalcitonin (PCT) in clinical practice is increasing, no data are available on procalcitonin during pregnancy. The purpose of this study was to investigate whether procalcitonin was present in the cervicovaginal secretion of pregnant women and, if so, to evaluate the practical value of determining the concentration.

STUDY DESIGN

A total of 53 patients in whom preterm labor (PTL) was expected and 31 healthy pregnant women were enrolled in this study. In the preterm labor group procalcitonin concentrations were analyzed with reference to laboratory indices suggestive of infection. The outcome of pregnancy was recorded in each case, with mention of the gestational age at delivery and of the time between admission to hospital and delivery.

RESULTS

Concentrations of procalcitonin in the preterm labor group were comparable to those in the healthy pregnant women. In the preterm labor group no significant correlations were observed between procalcitonin concentration and laboratory indices of infection. Nor were any correlations observed between procalcitonin concentration at the onset of preterm labor and gestational age either at the onset of labor or at delivery. However, procalcitonin concentrations at the onset of preterm labor were higher in patients who delivered prematurely than in those who delivered near term after treatment to delay labor. Procalcitonin concentrations in women whose babies were delivered within 3, 7 and 14 days of admission and in those whose babies were born at later times were comparable.

CONCLUSIONS

In this study, procalcitonin was determined in the cervicovaginal secretion of pregnant women for the first time. However, no association was observed either between procalcitonin concentration at the onset of preterm labor and laboratory signs of infection or between procalcitonin concentration and time between admission to hospital and delivery. Procalcitonin determination would be unsatisfactory as a prognostic indicator of the length of time between admission to hospital and delivery.