Intra-amniotic infection in patients with preterm prelabor rupture of membranes. Pathophysiology, detection, and management

Use of Vaginal Dinoprostone (PGE2) in Patients with Premature Rupture of Membranes (PROM) Undergoing Induction of Labor: A Comparative Study

Purpose: To evaluate the effect and safety of vaginal dinoprostone in pregnant women with PROM who undergo induction of labor (IoL). Materials and Methods: Prospective observational study conducted at La Mancha Centro hospital from 1 February 2019, to 30 August 2020. Obstetric and neonatal variables of 94 pregnant women with PROM who underwent IoL with vaginal dinoprostone were analyzed, and the results were compared with 330 patients without PROM who also underwent IoL. Bivariate and multivariate analyses were performed using binary and multiple linear regression. Results: A total of 424 women were included in this study. A greater response to cervical ripening (Bishop score > 6) with PGE2 was observed in the PROM group (odds ratio (OR) 2.73, 95% confidence interval (CI) 1.50−4.99, p = 0.001), as well as a shorter total duration of IoL (mean difference (MD) 2823.37 min (min), 95% CI 1257.30−4389.43, p < 0.001). Cesarean sections were performed in 28.7% (n = 27) of patients in the PROM group vs. 34.2% (n = 113) of patients in the non-PROM group, with no significant differences (OR 0.87%, 95% CI 0.47−1.60, p = 0.652). There were no significant differences in changes in the cardiotocographic record (CTG), postpartum hemorrhage (PPH), uterine rupture, or adverse neonatal outcomes between the two groups. Conclusions: The use of vaginal dinoprostone in pregnant women undergoing IoL with PROM is safe for the mother and the fetus, shortens the total delivery time, and does not increase the risk of cesarean section compared with pregnant women undergoing IoL without PROM.

Management of clinical chorioamnionitis: an evidence-based approach

This review aimed to examine the existing evidence about interventions proposed for the treatment of clinical chorioamnionitis, with the goal of developing an evidence-based contemporary approach for the management of this condition. Most trials that assessed the use of antibiotics in clinical chorioamnionitis included patients with a gestational age of ≥34 weeks and in labor. The first-line antimicrobial regimen for the treatment of clinical chorioamnionitis is ampicillin combined with gentamicin, which should be initiated during the intrapartum period. In the event of a cesarean delivery, patients should receive clindamycin at the time of umbilical cord clamping. The administration of additional antibiotic therapy does not appear to be necessary after vaginal or cesarean delivery. However, if postdelivery antibiotics are prescribed, there is support for the administration of an additional dose. Patients can receive antipyretic agents, mainly acetaminophen, even though there is no clear evidence of their benefits. Current evidence suggests that the administration of antenatal corticosteroids for fetal lung maturation and of magnesium sulfate for fetal neuroprotection to patients with clinical chorioamnionitis between 24 0/7 and 33 6/7 weeks of gestation, and possibly between 23 0/7 and 23 6/7 weeks of gestation, has an overall beneficial effect on the infant. However, delivery should not be delayed to complete the full course of corticosteroids and magnesium sulfate. Once the diagnosis of clinical chorioamnionitis has been established, delivery should be considered, regardless of the gestational age. Vaginal delivery is the safer option and cesarean delivery should be reserved for standard obstetrical indications. The time interval between the diagnosis of clinical chorioamnionitis and delivery is not related to most adverse maternal and neonatal outcomes. Patients may require a higher dose of oxytocin to achieve adequate uterine activity or greater uterine activity to effect a given change in cervical dilation. The benefit of using continuous electronic fetal heart rate monitoring in these patients is unclear. We identified the following promising interventions for the management of clinical chorioamnionitis: (1) an antibiotic regimen including ceftriaxone, clarithromycin, and metronidazole that provides coverage against the most commonly identified microorganisms in patients with clinical chorioamnionitis; (2) vaginal cleansing with antiseptic solutions before cesarean delivery with the aim of decreasing the risk of endometritis and, possibly, postoperative wound infection; and (3) antenatal administration of N-acetylcysteine, an antioxidant and antiinflammatory agent, to reduce neonatal morbidity and mortality. Well-powered randomized controlled trials are needed to assess these interventions in patients with clinical chorioamnionitis.

Differential Secretion of Matrix Metalloproteinase-2 and -9 After Selective Infection With Group B Streptococci in Human Fetal Membranes

OBJECTIVE

This study evaluated the secretions of zymogen and active forms of matrix metalloproteinase (MMP)-9 and MMP-2 and their specific inhibitors, TIMP-1 and TIMP-2 by fetal membranes stimulated with group B Streptoccocci (GBS).

METHODS

We used an in vitro experimental model that allowed us to estimate the individual contribution of the amnion (AM) and the choriodecidua (CHD) to the microbial insult. Membranes were obtained after delivery by elective cesarean delivery from women at 37 to 40 weeks of gestation without evidence of either active labor or intrauterine infection. Membranes were mounted in Transwell devices (Costar, New York, NY), physically separating the upper and lower chambers; 1 x 10(6) CFU of GBS was added to either AM or CHD and the secretions and gelatinolytic activity of MMP-2 and MMP-9 were measured in both compartments by enzyme-linked immunosorbent assay (ELISA) and zymography. TIMPs secretion was measured by ELISA. Both MMPs were immunolocalized in tissue sections.

RESULTS

The simultaneous stimulation at both sides was followed by increases of proMMP-9 (85.0 +/- 18.63 pg/mL) and proMMP-2 (4.10 +/- 1.90 ng/mL) in the CHD (P <.05). When only one side of the membrane was stimulated, the secretion level of proMMP-2 increased 2.3-fold and that of proMMP-9 2.5-fold in the CHD. The active forms of both enzymes did not change with any modality of stimulation. The secretion level of both TIMPs remained without significant changes. CHD and AM were positive for immunoreactive MMP-2 and MMP-9.

CONCLUSION

We propose that infection of fetal membranes with GBS is followed by active secretion of MMP and the CHD is the principal source of these mediators of extracellular matrix degradation.

Clinical chorioamnionitis at term II: the intra-amniotic inflammatory response

OBJECTIVE

Recent studies indicate that clinical chorioamnionitis is a heterogeneous condition and only approximately one-half of the patients have bacteria in the amniotic cavity, which is often associated with intra-amniotic inflammation. The objective of this study is to characterize the nature of the inflammatory response within the amniotic cavity in patients with clinical chorioamnionitis at term according to the presence or absence of 1) bacteria in the amniotic cavity and 2) intra-amniotic inflammation.

MATERIALS AND METHODS

A retrospective cross-sectional case-control study was conducted to examine cytokine and chemokine concentrations in the amniotic fluid (AF). Cases consisted of women with clinical chorioamnionitis at term (n=45). Controls were women with uncomplicated pregnancies at term who did not have intra-amniotic inflammation and were in labor (n=24). Women with clinical chorioamnionitis were classified according to the results of AF cultures, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry, and AF concentration of interleukin-6 (IL-6) into those: 1) without intra-amniotic inflammation, 2) with microbial-associated intra-amniotic inflammation, and 3) with intra-amniotic inflammation without detectable bacteria. The AF concentrations of 29 cytokines/chemokines were determined using sensitive and specific V-PLEX immunoassays.

RESULTS

1) The AF concentrations of pro- and anti-inflammatory cytokines/chemokines such as interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin-4 (IL-4), macrophage inflammatory protein-1 beta (MIP-1β), and interleukin-8 (IL-8) (except Eotaxin-3) were significantly higher in women with clinical chorioamnionitis at term than in controls (term labor without intra-amniotic inflammation); 2) patients with microbial-associated intra-amniotic inflammation, and those with intra-amniotic inflammation without detectable bacteria, had a dramatic differential expression of cytokines and chemokines in AF compared to patients with spontaneous labor without intra-amniotic inflammation. However, no difference could be detected in the pattern of the intra-amniotic inflammatory response between patients with intra-amniotic inflammation with and without detectable bacteria; and 3) in patients with clinical chorioamnionitis at term but without intra-amniotic inflammation, the behavior of cytokines and chemokines in the AF was similar to those in spontaneous labor at term.

CONCLUSIONS

Patients with clinical chorioamnionitis who had microbial-associated intra-amniotic inflammation or intra-amniotic inflammation without detectable bacteria had a dramatic upregulation of the intra-amniotic inflammatory response assessed by amniotic fluid concentrations of cytokines. A subset of patients with term clinical chorioamnionitis does not have intra-amniotic infection/inflammation, as demonstrated by elevated AF concentrations of inflammation-related proteins, when compared to women in term labor with uncomplicated pregnancies, suggesting over-diagnosis. These observations constitute the first characterization of the cytokine/chemokine network in the amniotic cavity of patients with clinical chorioamnionitis at term.

Regulation of TIMP-1 in Human Placenta and Fetal Membranes by lipopolysaccharide and demethylating agent 5-aza-2'-deoxycytidine

BACKGROUND

An appropriate transcriptional profile in the placenta and fetal membranes is required for successful pregnancy; any variations may lead to inappropriate timing of birth. Epigenetic regulation through reversible modification of chromatin has emerged as a fundamental mechanism for the control of gene expression in a range of biological systems and can be modified by pharmacological intervention, thus providing novel therapeutic avenues. TIMP-1 is an endogenous inhibitor of MMPs, and hence is intimately involved in maintaining the integrity of the fetal membranes until labor.

OBJECTIVE AND METHODS

To determine if TIMP-1 is regulated by DNA methylation in gestational tissues we employed an in vitro model in which gestational tissue explants were treated with demethylating agent 5-aza-2'-deoxycytidine (AZA) and lipopolysaccharide (LPS).

RESULTS

Quantitative Real-Time PCR (qRT-PCR) revealed that TIMP-1 transcription was significantly increased by combined treatment of AZA and LPS, but not LPS alone, in villous, amnion and choriodecidua explants after 24 and 48 hrs, whilst western blotting showed protein production was stimulated after 24 hrs only. Upon interrogation of the TIMP-1 promoter using Sequenom EpiTyper MassARRAY, we discovered sex-specific differential methylation, in part explained by x-linked methylation in females. Increased TIMP-1 in the presence of LPS was potentiated by AZA treatment, signifying that a change in chromatin structure, but not in DNA methylation at the promoter region, is required for transcriptional activators to access the promoter region of TIMP-1.

CONCLUSIONS

Collectively, these observations support a potential role for pharmacological agents that modify chromatin structure to be utilized in the therapeutic targeting of TIMP-1 to prevent premature rupture of the fetal membranes in an infectious setting.

Related factors and adverse neonatal outcomes in women with preterm premature rupture of membranes complicated by histologic chorioamnionitis

Background

The aim of this study was to identify factors predicting histologic chorioamnionitis (HCA) in women with preterm premature rupture of membranes (PPROM).

Material/Methods

We retrospectively enrolled 371 women diagnosed with PPROM at less than 34 weeks of gestation at the Second Affiliated Hospital of Wenzhou Medical University between January 2008 and December 2012. HCA was diagnosed by placental histopathology in 70% of participants. Binary logistic regression was used to identify factors associated with HCA and neonatal outcomes.

Results

Patient age, rate of parity, tocolysis, cesarean section, serum C reactive protein (CRP) level at admission, white blood cell count, and latency duration did not significantly differ between the 2 groups. Binary logistic regression revealed that oligohydramnios at admission, gestational age at PPROM, and serum CRP >8 mg/L before delivery were significantly associated with HCA. Gestational age at delivery and birth weight were significantly lower in HCA patients than control patients. The rate of 1-min Apgar score <7, abnormal neonatal intracranial ultrasound findings, neonatal pneumonia, bronchopulmonary dysplasia, early-onset neonatal sepsis, and mortality were higher in HCA patients, but no significant difference was observed in the incidence of neonatal respiratory distress syndrome, necrotizing enterocolitis, hyperbilirubinemia, or hypoglycemia.

Conclusions

Younger gestational age at time of PPROM, higher CRP level before delivery, and oligohydramnios at admission in women with PPROM are associated with HCA, and HCA is associated with some adverse neonatal outcomes.

Positive maternal C-reactive protein predicts neonatal sepsis

PURPOSE

To evaluate the diagnostic performance of maternal inflammatory marker: C-reactive protein (CRP) in predicting early onset neonatal sepsis (that occurring within 72 hours after birth).

MATERIALS AND METHODS

126 low birth weight newborns (gestation 32±3.2 wk, birth weight 1887±623 g) and their mothers were included. Neonates were divided into sepsis group (n=51) including both proven (positive blood culture) and suspected (negative blood culture but with more than 3 abnormal clinical signs), and controls (n=75). Mothers were subgrouped into CRP positive ≥1.22 mg/dL (n=48) and CRP negative <1.22 mg/dL (n=78) group, determined by Receiver Operating Characteristic curves, and odds ratio was calculated for neonatal sepsis according to maternal condition.

RESULTS

Maternal CRP was significantly higher in neonatal sepsis group than in control (3.55±2.69 vs. 0.48±0.31 mg/dL, p=0.0001). Maternal CRP (cutoff value >1.22 mg/dL) had sensitivity 71% and specificity 84% for predicting neonatal sepsis. Maternal CRP positive group had more neonatal sepsis than CRP negative group (71% vs. 29%, p<0.001). Odds ratio of neonatal sepsis in maternal CRP positive group versus CRP negative group was 10.68 (95% confidence interval: 4.313-26.428, p<0.001).

CONCLUSION

The risk of early onset neonatal sepsis significantly increased in the case of positive maternal CRP (≥1.22 mg/dL). In newborn of CRP positive mother, the clinician may be alerted to earlier evaluation for possible neonatal infection prior to development of sepsis.

Tissue-specific IL-10 secretion profile from term human fetal membranes stimulated with pathogenic microorganisms associated with preterm labor in a two-compartment tissue culture system

OBJECTIVE

Interleukin (IL)-10 is a cytokine with anti-inflammatory properties that plays pivotal roles in immune recognition and maintenance of pregnancy, limiting the harmful effects of pro-inflammatory modulators. The aim of this work was to characterize the contribution of amnion and choriodecidua regions of the human fetal membranes in the production of IL-10 after selective stimulation with Candida albicans, Gardnerella vaginalis and Streptococcus agalactiae.

METHODS

Pre-labor human fetal membranes were cultured in a two-compartment tissue culture system and stimulated with 1 × 10(6) CFU/ml of each pathogen added to either the amniotic or choriodecidual region or both.

RESULTS

Candida albicans and G. vaginalis were the pathogens most effective in inducing IL-10 secretion, increasing 20 and 10 times, respectively, the levels of this cytokine in the choriodecidual compartment. Stimulation with S. agalactiae was effective only in the choriodecidual region, increasing two times IL-10 concentration.

CONCLUSIONS

Synthesis and secretion of IL-10 in response to three different pathogens associated with intrauterine infection and preterm birth are differential and depend on the nature of the microorganism and initial contact region.

Tissue-specific human beta-defensins (HBD)-1, HBD-2 and HBD-3 secretion profile from human amniochorionic membranes stimulated with Candida albicans in a two-compartment tissue culture system

BACKGROUND

During intrauterine infection, amniochorionic membranes represent a mechanical and immunological barrier against dissemination of infection. Human beta defensins (HBD)-1, HBD-2, and HBD-3 are key elements of innate immunity that represent the first line of defense against different pathogen microorganisms associated with preterm labor. The aim of this work was to characterize the individual contribution of the amnion (AMN) and choriodecidua (CHD) regions to the secretion of HBD-1, HBD-2 and HBD-3, after stimulation with Candida albicans.

METHODS

Full-thickness human amniochorionic membranes were obtained after delivery by elective cesarean section from women at 37-40 wk of gestation with no evidence of active labor. The membranes were cultured in a two-compartment experimental model in which the upper compartment is delimited by the amnion and the lower chamber by the choriodecidual membrane. One million of Candida albicans were added to either the AMN or the CHD face or to both and compartmentalized secretion profiles of HBD-1, HBD-2, and HBD-3 were quantified by ELISA. Tissue immunolocalization was performed to detect the presence of HBD-1, -2, -3 in tissue sections stimulated with Candida albicans.

RESULTS

HBD-1 secretion level by the CHD compartment increased 2.6 times (27.30 [20.9-38.25] pg/micrograms protein) when the stimulus with Candida albicans was applied only on this side of the membrane and 2.4 times (26.55 [19.4-42.5] pg/micrograms protein) when applied to both compartments simultaneously. HBD-1 in the amniotic compartment remained without significant changes. HBD-2 secretion level increased significantly in the CHD when the stimulus was applied only to this region (2.49 [1.49-2.95] pg/micrograms protein) and simultaneously to both compartments (2.14 [1.67- 2.91] pg/micrograms protein). When the stimulus was done in the amniotic compartment HBD-2 remained without significant changes in both compartments. HBD-3 remained without significant changes in both compartments regardless of the stimulation modality. Localization of immune-reactive forms of HBD-1, HBD-2, and HBD-3 was carried out by immunohistochemistry confirming the cellular origin of these peptides.

CONCLUSION

Selective stimulation of amniochorionic membranes with Candida albicans resulted in tissue-specific secretion of HBD-1 and HBD-2, mainly in the CHD, which is the first region to become infected during an ascending infection.

Tissue-specific human beta-defensins (HBD)1, HBD2, and HBD3 secretion from human extra-placental membranes stimulated with Escherichia coli

BACKGROUND

During an ascending infection along the reproductive tract, the extra-placental membranes must act as a selective and competent barrier against pathogens. Human beta defensins (HBD)1, HBD2, and HBD3 are key elements of innate immunity that are secreted to neutralize/control the progression of infection.

METHODS

Full-thickness membranes were mounted on a Transwell device, constituted by two independent chambers, 1 × 10(6) CFU/ml of Escherichia coli were added to either the amnion (AMN) or the choriodecidual (CHD) face or to both. Secretion profiles of HBD1, HBD2, and HBD3 to the culture medium were quantified by ELISA.

RESULTS

In comparison with basal conditions, the secretion profile of HBD1 remained without significant changes; HBD2 level in CHD and AMN increased 1.9- and 1.4-times, respectively, after stimulation with bacteria. HBD3 secretion level increased significantly (7.8 +/- 1.9 pg/micrograms) in the CHD but only if the stimulus was applied on the AMN side.

CONCLUSIONS

Selective stimulation of extra-placental membranes with E. coli, results in a tissue specific secretion of HBD1, HBD2, and HBD3 mainly in the CHD, which is the first infected region during an ascending infection.

A systematic review of intentional delivery in women with preterm prelabor rupture of membranes

OBJECTIVE

To evaluate the effect of intentional delivery versus expectant management in women with preterm prelabor rupture of membranes (PPROM).

METHODS

We searched electronic databases and trials registries, contacted experts, and checked reference lists of relevant studies. Studies were included if they were randomized controlled trials comparing intentional delivery versus expectant management after PPROM, the gestational age of participants was between 30 and 36 weeks, and the study reported one of several pre-determined outcomes.

RESULTS

Four studies were included in the meta-analysis. No difference was found between intentional delivery and expectant management in neonatal intensive care unit (NICU) length of stay (LOS) (weighted mean difference (WMD) -0.81 day, 95% confidence interval (CI) -1.66, 0.04), respiratory distress syndrome (risk difference (RD) -0.01, 95% CI -0.07, 0.06), and confirmed neonatal sepsis (RD -0.01, 95% CI -0.05, 0.04). One study found a significantly lower incidence of suspected neonatal sepsis among the intentional delivery group (RD -0.31, 95% CI -0.50, -0.12; number needed to treat (NNT) 3, 95% CI 2, 8). Maternal LOS was significantly shorter for the intentional delivery group (WMD -1.39 day, 95% CI -2.03, -0.75). There was a significant difference in the incidence of clinical chorioamnionitis favoring intentional delivery (RD -0.16, 95% CI -0.23, -0.10; NNT 6, 95% CI 5, 11). There was no significant difference in the incidence of other maternal outcomes, including cesarean section (RD 0.05, 95% CI -0.01, 0.11).

CONCLUSIONS

Intentional delivery may be favorable to expectant management for some maternal outcomes (chorioamnionitis and LOS). There is insufficient evidence to suggest that either strategy is beneficial or harmful for the baby. Large multicenter trials with primary neonatal outcomes are required to assess whether intentional delivery is associated with less neonatal morbidity.

Pre-term pre-labour rupture of membranes: Effect of chorioamnionitis on overall neonatal outcome

Our objective was to evaluate the association between clinical chorioamnionitis following preterm pre-labour rupture of membranes (PPROM) and adverse neonatal outcome. We compared retrospectively, adverse neonatal outcome of singleton pregnancies with documented PPROM who developed chorioamnionitis (cases) with those who did not (controls). Our result showed that poor neonatal outcome was significantly associated with chorioamnionitis (34% vs 13%; p = 0.008). This association was found on multiple logistic regression analysis to be independent (p < 0.05) of other risk factors for poor neonatal outcome, viz: latency period (p = 0.002) and gestational age at delivery (p < 0.001). We conclude that chorioamnionitis complicating PPROM worsen neonatal outcome. The implication of this on expectant management of PPROM is discussed.

Association of preterm birth with sustained postnatal inflammatory response

OBJECTIVE

To investigate fetal or neonatal inflammatory patterns based on 25 inflammatory markers in neonatal dried blood spots samples from infants born preterm and term, collected several days after birth.

METHODS

Dried blood spots samples from 160 neonates were analyzed for 25 inflammatory markers using multiplex technology: 26 neonates born very preterm (before 32 weeks of gestation), drawn at a mean 6 days (95% confidence interval [CI], 5-7 days) after birth; 52 born preterm (32-36 weeks of gestation), drawn at mean 5 days (95% CI, 5-6 days) after birth; and 82 born at term (at or after 37 weeks of gestation), drawn at mean 5 days (95% CI, 5-5 days) after birth. Markers statistically significantly associated with preterm birth were analyzed in a multivariable model together with maternal and neonatal risk factors for preterm birth.

RESULTS

Elevated levels of interleukin (IL)-1beta, IL-6, soluble IL-6ralpha, IL-8, matrix metalloproteinase-9, and transforming growth factor-beta1 and decreased levels of IL-18, brain-derived neurotrophic factor, and C-reactive protein were associated with preterm birth. Maternal risk factors could explain only an increase of IL-1beta, whereas neonatal factors could explain several of the elevated and decreased inflammatory markers in the dried blood spots samples from the infants born preterm compared with the infants born at term.

CONCLUSION

The differences in levels of inflammatory markers in dried blood spots samples from infants born preterm compared with infants born at term supports the hypothesis that inflammation of fetal origin might be a cause of preterm birth.

LEVEL OF EVIDENCE

II.

Value of vaginal fluid proinflammatory cytokines for the prediction of early-onset neonatal infection in preterm premature rupture of the membranes

The usefulness of vaginal fluid proinflammatory cytokine assays in the prediction of neonatal congenital infection was evaluated. Sixty-two women between 24 and 34 weeks of pregnancy, complicated by premature rupture of the membranes, were divided into those who delivered newborns with (n = 21) and without (n = 41) signs of infection. Concentrations of all studied cytokines were higher in women who delivered babies with infection. The cutoff values of interleukin-1alpha (IL-1alpha) and IL-1beta > or = 400, IL-6 > or = 2000, and IL-8 > or = 2100 pg/mL predicted infection with a sensitivity of 57%, 57%, 33%, and 76%, a specificity of 73%, 73%, 93%, and 59%, a positive predictive value of 52%, 52%, 70%, and 48%, and a negative predictive value of 77%, 77%, 73%, and 83%, respectively. Receiver operating characteristic (ROC) curve analysis revealed that the predictive performance of the four studied cytokines was comparable. In conclusion, vaginal fluid cytokines after premature rupture of the membranes have moderately predictive value of whether or not a neonate will develop early sepsis.

Evidence of in vitro differential secretion of 72 and 92 kDa type IV collagenases after selective exposure to lipopolysaccharide in human fetal membranes

Premature rupture of chorioamniotic membranes complicated with intrauterine infection has been associated to degradation of extracellular matrix (ECM), which could explain local morphological changes. We used a culture system in which the chorioamniotic membranes form two independent chambers, allowing for the selective stimulation of either the amnion (AMN) and/or the choriodecidua (CHD) regions. Lipopolysaccharide (500 ng/ml) was added to the AMN and/or the CHD; secretions and gelatinolytic activity of matrix metalloproteinase (MMP)-2 and MMP-9 were measured in both compartments by enzyme-linked immunosorbent assay (ELISA) and zymography. Secretions of TIMP-1, TIMP-2 and TIMP-4 were measured by ELISA. Both metalloproteinases were immunolocalized in tissue sections. All stimulation modalities induced a similar proMMP-2 and proMMP-9 secretion pattern in the CHD with concentrations of 2.49 ng/ml and 90.91 pg/ml, respectively; the AMN showed no significant changes. The active forms of both enzymes did not change with any stimulation modality. TIMP-1, TIMP-2 and TIMP-4 secretions remained without significant changes (P = 0.41). ECM degradation and structural disarrangement were evident after stimulation. Secretion of proMMP-2 and proMMP-9 mainly in the CHD, presence of active forms associated to the tissue and minor changes in TIMPs secretion could favor ECM degradation and explain the weakening and thinning associated with the pathological rupture of chorioamniotic membranes.

Possible early prediction of preterm birth by determination of novel proinflammatory factors in midtrimester amniotic fluid

Interferon-gamma-inducible T cell-alpha chemoattractant (ITAC) is a chemokine, directing activated T lymphocytes toward sites of inflammation. ADAM-8 (A disintegrin and metalloprotease-8) is a glycoprotein expressed in cells promoting inflammation. Elastase, a protease targeting at the degradation of intra- or extracellular proteins, is inhibited by secretory leukocyte proteinase inhibitor (SLPI), which protects against microbial invasion. Adhesion molecules (soluble intercellular adhesion molecule--sICAM-1 and soluble vascular cell adhesion molecule-sVCAM--1) serve as markers of inflammation or tissue damage. We hypothesized that elevated midtrimester amniotic fluid concentrations of above substances, and decreased levels of SLPI could possibly be useful predictors of asymptomatic intra-amniotic inflammation and/or infection, eventually resulting in preterm labor and delivery. The study involved 312 women undergoing midtrimester amniocentesis. Thirteen cases, progressing to preterm delivery (<37 weeks), were matched with 21 controls (delivering >37 weeks) for age, parity, and gestational age at amniocentesis. Amniotic fluid levels of the above substances were measured by enzyme-linked immunosorbent assay (ELISA). Only amniotic fluid ITAC and ADAM-8 levels were significantly higher (P=0.005 and P < 0.02, respectively) in women delivering at <37 weeks than at >37 weeks. SLPI concentrations significantly increased in women going into labor without ruptured membranes irrespective of pre- or term delivery (P < 0.007, P < 0.001, respectively) and correlated with elastase (r=0.508, P < 0.002). In conclusion, elevated midtrimester amniotic fluid levels of ITAC and ADAM-8 could predict occult infections/inflammations, possibly resulting in preterm birth.

Elevated second trimester amniotic fluid interferon gamma-inducible T-cell alpha chemoattractant concentrations as a possible predictor of preterm birth

OBJECTIVE

To determine and correlate midtrimester amniotic fluid concentrations of interferon gamma-inducible T-cell alpha chemoattractant (ITAC, a chemokine directing the migration of activated T lymphocytes toward inflammation sites) and C-reactive protein (CRP) in women undergoing amniocentesis and subsequently delivering pre-or full-term infants.

METHODS

Among 312 women undergoing midtrimester transabdominal amniocentesis, 13 progressed to spontaneous delivery at less than 37 gestational weeks (GW). Subjects were matched for maternal age, parity, and GW at amniocentesis with 21 controls who delivered at greater than 37 GW. Amniotic fluid ITAC and CRP levels were determined by enzyme-linked immunosorbent assay (ELISA) and by nephelometry, respectively.

RESULTS

Both ITAC and CRP values were significantly higher (P = .005 and P = .04, respectively) in the amniotic fluid of women delivering at less than 37 GW. A statistically significant correlation between amniotic fluid ITAC and CRP concentrations was also found (r = .366, P < .05). The receiver operator curve (ROC) analysis of delivery at less than 37 GW gave the best cutoff point for ITAC at a concentration of 44 pg/mL and for CRP at a concentration of 0.16 mg/dL. Positive and negative predictive values for ITAC were 82% and 85%, respectively, and for CRP, 55% and 76%, respectively.

CONCLUSIONS

Present data indicate that from the second trimester of pregnancy elevated amniotic fluid concentrations of ITAC are found in women delivering at less than 37 GW, as compared to women delivering at term. Therefore, ITAC in combination with other cytokines or CRP could possibly serve as predictor of preterm delivery.

Incubation of human chorioamniotic membranes with Candida albicans induces differential synthesis and secretion of interleukin-1beta, interleukin-6, prostaglandin E, and 92 kDa type IV collagenase

Ascendant colonization of pathogenic microorganisms from the vagina to the uterus is strongly associated to preterm labour and premature rupture of membranes. This study evaluated the secretion of interleukin (IL)-1beta, tumour necrosis factor (TNF)alpha, IL-6, prostaglandin E(2) (PGE(2)), and metalloproteinases 9 and 2 by the human chorioamnion stimulated with Candida albicans. Chorioamniotic membranes were obtained after delivery by elective Cesarean section from women at 37-40 weeks of gestation without evidence of active labour. The membranes were mounted in Transwell devices that form two independent compartments, which allow testing the individual responses and contributions of the amnion and choriodecidua. One million CFU ml(-1) of C. albicans was added to either the amniotic or choriodecidual surface and secretions of the markers were measured in both compartments using specific enzyme-linked immunosorbent assay and zymography. Fetal membranes followed different secretion patterns of proinflammatory cytokines depending on the side to which the stimulus was applied. IL-1beta was produced in higher amounts in the presence of C. albicans when applied to the choriodecidual side; TNFalpha and IL-6 secretion did not change in either the amnion or choriodecidual region. PGE(2) synthesis depicted a different pattern, the amniotic tissue was more responsive than the choriodecidual tissue, and this response tended to be higher even when only the amniotic side was stimulated. Matrix metalloproteinases (MMP)-9 increased after stimulation, being the choriodecidua its main source. Selective stimulation with C. albicans induced a differential secretion of IL-1beta, PGE(2), and MMP-9, resulting from a cooperative and bidirectional communication between the amnion and the choriodecidua.

Population cohort associating chorioamnionitis, cord inflammatory cytokines and neurologic outcome in very preterm, extremely low birth weight infants

Intrauterine inflammation may relate to neurologic disability among preterm children. We investigated the relationship between chorioamnionitis, cord serum cytokines, and neurologic outcome. Sixty-one consecutively born very preterm extremely low birth weight (ELBW) infants were prospectively enrolled. Histologic inflammation in placenta and umbilical cord and vascular pathology were evaluated. Cord sera were analyzed for five proinflammatory cytokines. Serial brain ultrasound and magnetic resonance imaging were performed for evaluation of intraventricular hemorrhage (IVH grade I-III) and white matter damage (WMD: cystic periventricular leukomalacia or IVH grade IV). Neurologic and neurocognitive outcomes were assessed at the corrected age of 2 y. The incidences of HCA, WMD, and abnormal neurologic outcome were 48%, 13% and 19%, respectively. HCA or high IL-6 in cord serum predicted spontaneous preterm labor with high accuracy. HCA increased the risk of IVH grade II-III. In HCA, without either clinical chorioamnionitis or histologic placental perfusion defect, the children had a low risk of WMD (0%) and a low risk of abnormal neurologic outcome (6%). In HCA, the concentration of IL-6 in cord serum was lower in children with abnormal neurologic outcome than in children with normal neurologic outcome. In HCA and placental perfusion defect (compound defect) the risk of abnormal neurologic outcome was high. Compound placental defect and WMD additively predicted abnormal neurologic outcome. We propose that HCA together with other insults (placental perfusion defect or maternal systemic infection) increases the risk of poor neurologic outcome in very preterm ELBW infants.

Maternal C-reactive protein for detection of chorioamnionitis: an appraisal

Premature delivery is still a significant problem in obstetrics, and chorioamnionitis is an unwelcome complication. C-reactive protein (CRP) is a circulating marker of low-grade inflammation and the role of its measurement in clinical practice remains unclear for many conditions. It has been claimed that estimation of CRP is helpful in the diagnosis of chorioamnionitis, and this study aims to appraise such claims. Following review of the literature, six reports were recruited for further metanalysis, including 466 cases. The overall prevalence of chorioamnionitis was 41% (191/466). The overall diagnostic activity showed sensitivity, specificity, false-positives and false-negatives of 72.8%, 76.4%, 23.6% and 27.2%, respectively. Therefore, we can conclude that estimation of maternal CRP is not helpful in the detection of chorioamnionitis, compared with standard investigations.

Interleukin-6 in preterm premature rupture of membranes as an indicator of neonatal outcome

BACKGROUND

The aim of this study was to investigate whether the levels of interleukin-6 (IL-6) can be used as markers of adverse outcome in preterm neonates born after preterm premature rupture of membranes (PPROM).

METHODS

This study involved 109 preterm neonates and their mothers. The PPROM group consisted of 58 neonates who were born after PPROM, and the control group consisted of 51 neonates. IL-6 levels were measured in umbilical cord blood, maternal blood sampled during delivery and in neonatal blood taken on the fourth day of life.

RESULTS

In the PPROM group, IL-6 concentrations in maternal blood, cord blood, and neonatal blood were significantly higher in neonates with sepsis, compared with those without sepsis (P < 0.001). Choosing 108.5 pg/ml as a cut-off concentration of IL-6 in umbilical cord blood for neonatal sepsis resulted in sensitivity 95%, specificity 100%, positive predictive value 100%, and negative predictive value 97.4%. Concerning IL-6 in maternal blood, a cut-off concentration of 81 pg/ml showed sensitivity 90%, specificity 97.4%, positive predictive value 94.7%, and negative predictive value 94.9%. Eighteen of 20 neonates with early sepsis and seven of nine neonates, who died in the PPROM group, were born of mothers with IL-6 levels above the cut-off concentration in their blood during delivery.

CONCLUSIONS

IL-6 in umbilical cord blood was the most significant variable for predicting early onset sepsis in preterm neonates. IL-6 in maternal blood was indicative of intrauterine environmental threats and might be used to identify pregnancies where intervention would be appropriate.

Preterm premature rupture of membranes: diagnosis, evaluation and management strategies

Preterm premature rupture of the membranes (PPROM) is responsible for one-third of all preterm births and affects 120,000 pregnancies in the United States each year. Effective treatment relies on accurate diagnosis and is gestational age dependent. The diagnosis of PPROM is made by a combination of clinical suspicion, patient history and some simple tests. PPROM is associated with significant maternal and neonatal morbidity and mortality from infection, umbilical cord compression, placental abruption and preterm birth. Subclinical intrauterine infection has been implicated as a major aetiological factor in the pathogenesis and subsequent maternal and neonatal morbidity associated with PPROM. The frequency of positive cultures obtained by transabdominal amniocentesis at the time of presentation with PPROM in the absence of labour is 25-40%. The majority of amniotic fluid infection in the setting of PPROM does not produce the signs and symptoms traditionally used as diagnostic criteria for clinical chorioamnionitis. Any evidence of infection by amniocentesis should be considered carefully as an indication for delivery. Documentation of amniotic fluid infection in women who present with PPROM enables us to triage our therapeutic decision making rationally. In PPROM, the optimal interval for delivery occurs when the risks of immaturity are outweighed by the risks of pregnancy prolongation (infection, abruption and cord accident). Lung maturity assessment may be a useful guide when planning delivery in the 32- to 34-week interval. A gestational age approach to therapy is important and should be adjusted for each hospital's neonatal intensive care unit. Antenatal antibiotics and corticosteroid therapies have clear benefits and should be offered to all women without contraindications. During conservative management, women should be monitored closely for placental abruption, infection, labour and a non-reassuring fetal status. Women with PPROM after 32 weeks of gestation should be considered for delivery, and after 34 weeks the benefits of delivery clearly outweigh the risks.

Chorioamnionitis increases neonatal morbidity in pregnancies complicated by preterm premature rupture of membranes

OBJECTIVE

To compare morbidities of neonates born to women who developed chorioamnionitis after premature preterm rupture of membranes versus those who did not.

STUDY DESIGN

We reviewed outcomes in singleton pregnancies with confirmed premature preterm rupture of membranes at 24 weeks or beyond that resulted in delivery less than 37 weeks. Management of premature preterm rupture of membranes included the use of antibiotics, betamethasone if less than 32 weeks, and expectant management with induction at 34 weeks or greater. Composite neonatal major and minor morbidity rates were compared between pregnancies complicated by chorioamnionitis and those that were not.

RESULTS

From August 1998 to August 2000, 430 cases of premature preterm rupture of membranes were identified among 6003 deliveries (7.2%). Thirteen percent of women (56/430) with premature preterm rupture of membranes developed chorioamnionitis. The incidence of chorioamnionitis increased significantly with decreasing gestational age. The composite neonatal major morbidity rate was significantly higher in neonates whose mothers developed chorioamnionitis (55%) versus those who did not (18%, P < .0001). In a multiple logistic regression model, chorioamnionitis ( P < .0001), infant gender ( P = .007), latency ( P = .03), and gestational age at delivery ( P < .0001) were significantly associated with composite neonatal morbidity.

CONCLUSION

Neonatal morbidities are significantly higher among pregnancies with premature preterm rupture of membranes complicated by chorioamnionitis when compared with pregnancies that were not.

Histologic chorioamnionitis: an occult marker of severe pulmonary hypertension in the term newborn

OBJECTIVE

To determine whether the presence of histologic chorioamnionitis is associated with the severity of Persistent Pulmonary Hypertension of the Newborn (PPHN) as evidenced by the use of exogenous nitric oxide (iNO), high-frequency oscillatory ventilation (HFOV), extra-corporeal membrane oxygenation (ECMO) and/or death.

METHODS

Retrospective chart review of term neonates > or =37 weeks gestation with PPHN. Placental pathology was reviewed. Primary outcome is the use of iNO. Secondary outcomes include the use of HFOV, ECMO and death.

RESULTS

Over 2 years, 29 neonates fulfilled the entry criteria for the study. Interventions included iNO use n=14 (48%), HFOV n=7 (24%) and ECMO n=3 (10%); two neonates died. Histologic chorioamnionitis and/or funisitis was noted in 16 (55%) neonates. The presence of chorioamnionitis and/or funisitis (n=16) versus neither (n=13) was significantly associated with iNO use 11/16 (78%) versus 3/13 (22%) (p=0.02) and HFOV 7/16 (43%) versus 0/13 (0%) (p=0.008) but not to ECMO or death.

CONCLUSION

The presence of histologic chorioamnionitis and/or funisitis is associated with more severe PPHN as indicated by the use of iNO as well as an increased requirement for more advanced respiratory support, that is, HFOV. The mechanism/s contributing to these findings are unclear.

Preterm Premature Rupture of Membranes: Is There an Optimal Gestational Age for Delivery?

OBJECTIVE

To characterize neonatal and maternal morbidity and mortality rates in pregnancies complicated by preterm premature rupture of membranes (PROM) and determine whether there is an optimal delivery gestational age.

METHODS

We reviewed maternal and neonatal outcomes of women with PROM 24 weeks or more that resulted in delivery at less than 37 weeks at our institution from August 1998 to August 2000. Standardized management included the use of antibiotics, betamethasone at less than 32 weeks, and expectant management until 24 weeks or more. Outcomes evaluated included neonatal mortality, composite major and minor neonatal morbidity, individual major and minor neonatal morbidity rates, maternal infection morbidity, and maternal and neonatal length of stay. Gestational age-specific maternal and neonatal outcomes were compared with a referent group of pregnancies complicated by preterm PROM that delivered between 36 0/7 and 36 6/7 weeks of gestation.

RESULTS

During the study interval, 430 women with preterm PROM were identified. Composite major neonatal morbidity was significantly higher among pregnancies delivered at 33 weeks of gestation or less after preterm PROM as compared with those who delivered at 36 weeks. Composite neonatal minor morbidity was significantly higher among pregnancies delivered at 34 weeks or less after preterm PROM as compared with those who delivered at 36 weeks. However, there was no improvement in the composite major and minor neonatal morbidity rates for those pregnancies delivered beyond 34 weeks of gestation. Both maternal and infant length of stay were significantly longer for cases of preterm PROM delivered at 34 weeks or less as compared with those who delivered at 36 weeks.

CONCLUSION

Our findings suggest that expectant management of women at 34 weeks and beyond is of limited benefit.

Secretions of interleukin-1beta and tumor necrosis factor alpha by whole fetal membranes depend on initial interactions of amnion or choriodecidua with lipopolysaccharides or group B streptococci

The present study evaluated the secretions of interleukin (IL)-1beta and tumor necrosis factor (TNF) alpha by fetal membranes stimulated with group B streptococci (GBS) and lipopolysaccharide (LPS). The aim was to evaluate the initial response of full-thickness membranes to the microbial insult using an in vitro experimental model that allowed testing of the individual contributions of amnion and choriodecidua to stimulation. Full-thickness membranes were obtained after delivery by elective cesarean section from women at 37-40 wk of gestation without evidence of active labor. The membranes were mounted in Transwell devices, physically separating the upper and lower chambers. The LPS (500 ng/ml) or GBS (1 x 10(6) colony-forming units/ml) was added to either the amniotic or choriodecidual surface, and accumulation of IL-1beta and TNFalpha were measured in both compartments using a specific ELISA. Fetal membranes followed different patterns of secretion of proinflammatory cytokines that depended on the side to which the stimulus was added or the nature of the stimulus itself. The TNFalpha was secreted by amnion and choriodecidua in the presence of LPS or GBS, and stimulation with GBS induced a greater synthesis of IL-1beta than did stimulation with LPS. Choriodecidual tissue was more responsive than amniotic tissue, and this response tended to be higher even when the stimulation was only on the amniotic side. However, the amnion plays an active role in recognizing LPS or GBS, contributing a significant amount of TNFalpha. Thus, cooperative and bidirectional communications occur between amnion and choriodecidua in response to bacterial products, which include intermembranous cytokine traffic and signaling between tissues.

Microbial invasion and cytokine response in amniotic fluid in a Swedish population of women with preterm prelabor rupture of membranes

BACKGROUND

Previous studies have shown an association between intra-amniotic microbial invasion and/or inflammation and spontaneous preterm birth. The aim of this study was to investigate the occurrence of intra-amniotic microorganisms and cytokines [interleukin (IL)-6 and IL-8] in a Swedish population, with low incidence of preterm birth, of women with preterm prelabor rupture of membranes and their correlation to preterm birth.

METHODS

Amniotic fluid was retrieved transabdominally from 58 patients with preterm prelabor rupture of membranes before 34 weeks of gestation. Polymerase chain reaction (PCR) analyses for Ureaplasma urealyticum and Mycoplasma hominis and culture for aerobic and anaerobic bacteria were performed. IL-6 and IL-8 were analyzed with enzyme-linked immunosorbent assay (ELISA).

RESULTS

Microorganisms in amniotic fluid were detected in 13 patients (25%). Patients with bacteria detected in the amniotic fluid had significantly higher levels of IL-6 and IL-8. An amniotic fluid concentration of IL-6 >/= 0.80 ng/ml [relative risk 1.93, 95% confidence interval (CI) 1.13-3.29, sensitivity 63%, specificity 75%] was associated with an increased risk of delivery within 7 days. There was also an association between IL-8 and preterm birth (< 34 weeks).

CONCLUSIONS

Intra-amniotic microbial invasion and inflammation in this population of Swedish women with preterm prelabor rupture of membranes were similar to data reported from populations with a higher incidence of preterm delivery. Amniotic IL-6 correlated to the presence of microorganisms and delivery within 7 days and IL-8 to delivery before 34 weeks.

Production of matrix metalloproteinase-9 in lipopolysaccharide-stimulated human amnion occurs through an autocrine and paracrine proinflammatory cytokine-dependent system

The objective of this study was to determine the presence of autocrine/paracrine regulation of matrix metalloproteinase-9 (MMP-9) expression mediated by proinflammatory cytokines in human fetal membranes. Fetal membranes obtained from women who underwent cesarean delivery before labor were manually separated into amnion and chorion layers and maintained in culture. These explants were stimulated with tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and either lipopolysaccharide (LPS) alone or LPS with anti-TNFalpha or anti-IL-1beta-neutralizing antibodies. Levels of proMMP-9 in culture media were evaluated by zymography. Enzyme-linked immunosorbant assay was performed to measure the quantity of IL-1beta, TNFalpha, and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) after LPS stimulation. ProMMP-9 activity was upregulated after stimulation of the amnion by LPS, TNFalpha, and IL-1beta. The increased activity of proMMP-9 resulting from LPS stimulation in the amnion was blocked by the addition of TNFalpha neutralizing antibody but not with anti-IL-1beta. No significant effect of LPS, TNFalpha, or IL-1beta on proMMP-9 expression was observed in the chorion; however, the chorion produced both cytokines when stimulated with LPS. In contrast, TIMP-1 levels remained unchanged in all cultures incubated in the presence of LPS. Therefore, these data indicate that proMMP-9 is produced by the amnion but not the chorion in response to LPS. Because anti-TNFalpha-neutralizing antibody inhibits proMMP-9 activity in the amnion, TNFalpha appears to upregulate proMMP-9 production by the amnion in an autocrine fashion. Meanwhile, TNFalpha and IL-1beta produced by the chorion may upregulate amnionic proMMP-9 production in a paracrine manner.

Therapies administered to mothers at risk for preterm birth and neurodevelopmental outcome in their infants

A decrease in the rate of preterm births and the prevention of prematurity-associated neurodevelopmental morbidity are critical for the reduction of neurodevelopmental disability. Efforts to reduce the overall preterm delivery rate have been unsuccessful. Although progress has been achieved in the prevention of short-term neonatal morbidity over the past several decades, the majority of the improvements have resulted from improved neonatal care. Whether obstetric interventions can improve neurodevelopmental outcome is unknown. The ability to adequately assess obstetric interventions is hampered by the limited number of interventional studies that included long-term outcome assessment. Thus, it is incumbent upon ongoing and future interventional studies to consider long-term outcome assessment as a critical component of the overall evaluation of efficacy of obstetric therapies.