Epidural analgesia and maternal fever: a clinical and research update

Dexmedetomidine improves mitophagy and pyroptosis through the ALKBH5/FUNDC1 axis during epidural-related maternal fever

PURPOSE

Epidural analgesia has emerged as a commonly used method for relieving labor pain. However, epidural-related maternal fever (ERMF) is characterized by a high occurrence rate and can have detrimental consequences for the well-being of both the mother and the fetus. This study aimed to investigate the functional role and underlying mechanism of dexmedetomidine (DEX) in ERMF.

MATERIALS AND METHODS

Ropivacaine (ROP)-induced human umbilical vein endothelial cells (HUVECs) were treated with DEX and/or transfected with ALKBH5 or FUNDC1 overexpression plasmid. qPCR and Western blot were adopted for mitophagy and pyroptosis marker protein detection. Autophagosomes were observed through electron microscopy, Caspase-1/PI double-positive cells were determined using flow cytometry. Inflammation-related factors were quantified using ELISA. The N6-methyladenosine (m6A) modification of FUNDC1 mRNA was examined using methylated RNA immunoprecipitation (MeRIP) and the binding between ALKBH5 and FUNDC1 mRNA was confirmed by RNA immunoprecipitation (RIP).

RESULTS

In ROP-induced HUVECs, there was a significant upregulation in ALKBH5 and FUNDC1, resulting in a notable increase in inflammation, pyroptosis, and mitophagy. The administration of DEX demonstrated the ability to alleviate ROP-induced pyroptosis and promote protective mitophagy. Interestingly, DEX treatment significantly reduced the interaction between ALKBH5 and FUNDC1 mRNA, while simultaneously increasing the m6A level of FUNDC1 mRNA in ROP-treated cells. Moreover, the overexpression of FUNDC1 partially reversed the effects of ALKBH5 overexpression on mitophagy and pyroptosis in HUVECs.

CONCLUSIONS

DEX can promote mitophagy and inhibit pyroptosis through the ALKBH5/FUNDC1 axis in ERMF, indicating its potential as a therapeutic strategy for clinical ERMF treatment.

Maternal intrapartum fever during epidural labour analgesia: Incidence and influencing factors

BACKGROUND

The management and nursing care of women's temperature during delivery is an important part of clinical obstetrics. We aimed to evaluate maternal intrapartum fever during epidural labour analgesia to provide evidence for the management and care of women in labour.

METHODS

This study was conducted and reported according to the STROBE statement. Women in labour undergoing epidural labour analgesia in our hospital from 1 January 2021 to 31 August 2022 were retrospectively selected. The characteristics of women in labour with and without intrapartum fever were compared. Pearson correlation and logistic regression analysis were used to analyse the influencing factors of postpartum fever.

RESULTS

A total of 196 women in labour were included, the incidence of maternal intrapartum fever in women in labour undergoing epidural analgesia was 27.5%. Pearson correlation analyses showed that BMI, oxytocin use, labour duration, number of vaginal examinations, time from rupture of the foetal membranes to the end of labour and duration of epidural analgesia were all correlated with the occurrence of intrapartum fever (all P < 0.05). Logistic regression analyses indicated that body mass index ≥28 kg/m2 (OR = 1.825), oxytocin use (OR = 2.082), labour duration ≥9.2 h (OR = 2.613), number of vaginal examinations ≥8 (OR = 2.044-3.115), the time from rupture of the foetal membranes to the end of labour ≥250 min (OR = 2.766) and duration of epidural analgesia ≥300 min (OR = 3.106) were risk factors for intrapartum fever in women in labour undergoing epidural analgesia (all P < 0.05).

CONCLUSIONS

Maternal intrapartum fever in women in labour undergoing epidural analgesia is common and influenced by many factors. Nurses should take early preventive care measures according to these factors during epidural analgesia in labour.

Intrapartum Maternal Fever and Long-Term Infectious Morbidity of the Offspring

Maternal intrapartum fever can lead to various maternal and neonatal complications and is attributed to various etiologies including infectious and non-infectious processes. In this study, we evaluated whether intrapartum fever affects the offspring's tendency to long-term infectious morbidity. A population-based cohort analysis including deliveries between 1991 and 2021 was conducted. The incidence of hospitalizations of the offspring up to the age of 18 years, due to various infectious conditions, was compared between pregnancies complicated by intrapartum fever and those that were not. A Kaplan-Meier survival curve was used to assess cumulative hospitalization incidence. A Cox proportional hazards model was used to control for confounders. Overall, 538 of the 356,356 included pregnancies were complicated with fever. A higher rate of pediatric hospitalizations due to various infectious conditions was found among the exposed group, which was significant for viral, fungal and ENT infections (p < 0.05 for all). The total number of infectious-related hospitalizations was significantly higher (30.1% vs. 24.1%; OR = 1.36; p = 0.001), as was the cumulative incidence of hospitalizations. This association remained significant after controlling for confounders using a Cox proportional hazards model (adjusted HR = 1.21; 95% CI 1.04-1.41, p = 0.016). To conclude, fever diagnosed close to delivery may influence offspring susceptibility to pediatric infections.

Outcomes associated with antibiotic administration for isolated maternal fever in labor

BACKGROUND

The American College of Obstetricians and Gynecologists currently recommends that antibiotic treatment should be considered for women with isolated maternal fevers during labor. However, there is little known about the maternal and neonatal impact of antibiotic treatment in this scenario.

OBJECTIVE

We sought to assess the outcomes in women with a nonsustained, isolated maternal fever treated with antibiotics and compare it with expectant management.

STUDY DESIGN

This was a retrospective cohort study of laboring women with a singleton gestation at term and a single temperature of between 38.0°C and 38.9°C without other evidence of infection (leukocytosis >15,000/mm³, fetal tachycardia, malodorous amniotic fluid, suspected alternate source of infection) at a tertiary teaching hospital. A contemporaneously maintained, validated obstetrical database was used to identify women for our cohort. Women with rheumatologic or renal disease, nongestational diabetes, preterm labor, placental abruption, vaginal bleeding, HIV, malpresentation, and fetal anomalies were excluded. The primary outcome was a postpartum fever above 38.0°C. Secondary maternal outcomes were treatment for postpartum endometritis, uterine atony, postpartum hemorrhage, admission to the intensive care unit, and postpartum length of stay. Secondary neonatal outcomes were neonatal intensive care unit admission, 5-minute Apgar score of <7, 5-minute Apgar score of <4, neonatal intensive care unit length of stay, and neonatal antibiotic administration. The results were compared using univariable and multivariable analyses.

RESULTS

From January 1, 2015, to December 31, 2018, 359 women were identified; 85 received antibiotics and 274 did not. The baseline characteristics were similar between the groups, except for gestational age at the time of delivery (39.2 weeks vs 39.5 weeks for the antibiotic and no antibiotic groups, respectively; P=.02). The incidence in postpartum fever showed a downward trend in the antibiotic group (10.59% for the antibiotic group vs 18.98% for the no antibiotic group; P=.07). Significantly fewer women in the antibiotic group were treated for postpartum endometritis (3.53% vs 11.31%; P=.03). Neonatal intensive care unit admission and neonatal antibiotic administration rates were higher in the antibiotic group (41.18% vs 17.88%; P<.001 and 36.47% vs 12.41%; P<.001, respectively). The incidence of 5-minute Apgar score of <7 was higher in the antibiotic group (8.25% vs 2.19%; P=.016). After controlling for age, gestational age, body mass index, group B streptococci status, delivery method, parity, administration of epidural, and receipt of acetaminophen, the odds for postpartum fever were reduced by a factor of 0.42 (95% confidence interval, 0.18-0.99) among women who received antibiotics when compared with those who did not receive antibiotics. Outcome results are presented in Table 2.

CONCLUSION

Although there was a lower rate of treatment for endometritis among women who received antibiotics for a single isolated maternal fever, there was a higher rate of neonatal intensive care unit admissions and 5-minute Apgar score of <7. This indicates that there likely is maternal benefit associated with antibiotic use, however, there are concerns about the neonatal risk.

Acupoint Injection Decreases Anesthetic Cosumption during Combined Spinal-Epidural and Patient-Controlled Epidural Labor Analgesia

OBJECTIVE

To explore if acupoint injection can improve analgesic effects or delivery outcomes in parturients who received combined spinal-epidural analgesia (CSEA) and patient-controlled epidural analgesia (PCEA) for labor analgesia.

METHODS

A total of 307 participants were prospectively collected from July 2017 to December 2019. The participants were randomized into the combined acupoint injection with CSEA plus PCEA group (AICP group, n=168) and CSEA plus PCEA group (CP group, n=139) for labor analgesia using a random number table. Both groups received CSEA plus PCEA at cervical dilation 3 cm during labor process, and parturients of the AICP group were implemented acupoint injection for which bilateral acupoint of Zusanli (ST 36) and Sanyinjiao (SP 6) were selected in addition. The primary outcome was Visual Analogue Scale (VAS) score, and the secondary outcomes were obstetric outcomes and requirement of anesthetics doses. Safety evaluations were performed after intervention.

RESULTS

The VAS scores were significantly lower in the AICP group than in the CP group at 10, 30, 60, and 120 min after labor analgesia (all P<0.05). The latent phase of the AICP group was shorter than that of the CP group (P<0.05). There were less additional anesthetics consumption, lower incidences of uterine atony, fever, pruritus and urinary retention in the AICP group than those in the CP group (all P<0.05).

CONCLUSION

Acupoint injection combined CSEA plus PCEA for labor analgesia can decrease the anesthetic consumption, improve analgesic quality, and reduce adverse reactions in the parturients. (Registration No. ChiMCTR-2000003120).

Intrapartum and Postpartum Management of Intra-amniotic Infection

Importance

Intra-amniotic infection (IAI) is a common condition with potentially devastating maternal and neonatal complications. However, there are incomplete data regarding the most effective antimicrobial treatment regimen for this condition.

Objective

This article aims to review the current evidence and recommendations for intrapartum and postpartum management of IAI.

Evidence Acquisition

Original research articles, review articles, and guidelines on IAI were reviewed.

Results

Numerous known risk factors for IAI exist, some of which are modifiable. Serious neonatal complications can result from exposure to IAI including increased risk of preterm birth and neonatal death. Possible maternal complications include increased risk of cesarean delivery, postpartum hemorrhage, and postpartum endometritis. Antibiotics are the mainstay of treatment for IAI for both mothers and neonates, although there is no consensus on which antimicrobial agents are best and the appropriate duration of therapy.

Conclusions and Relevance

Monitoring patients for signs of IAI, proper treatment, and communication of the diagnosis with the pediatric team are essential for preventing maternal and neonatal complications of IAI. More research is needed to determine the proper treatment regimens for both mothers diagnosed with IAI and their neonates.

Nomogram for perinatal prediction of intrapartum fever: a retrospective case-control study

Objective

To explore the risk factors for intrapartum fever and to develop a nomogram to predict the incidence of intrapartum fever.

Methods

The general demographic characteristics and perinatal factors of 696 parturients who underwent vaginal birth at the Affiliated Hospital of Xuzhou Medical University from May 2019 to April 2020 were retrospectively analysed. Data was collected from May 2019 to October 2019 on 487 pregnant women who formed a training cohort. A multivariate logistic regression model was used to identify the independent risk factors associated with intrapartum fever during vaginal birth, and a nomogram was developed to predict the occurrence. To verify the nomogram, data was collected from January 2020 to April in 2020 from 209 pregnant women who formed a validation cohort.

Results

The incidence of intrapartum fever in the training cohort was found in 72 of the 487 parturients (14.8%), and the incidence of intrapartum fever in the validation cohort was 31 of the 209 parturients (14.8%). Multivariate logistic regression analysis showed that the following factors were significantly related to intrapartum fever: primiparas (odds ratio [OR] 2.43; 95% confidence interval [CI] 1.15–5.15), epidural labour analgesia (OR 2.89; 95% CI 1.23–6.82), premature rupture of membranes (OR 2.37; 95% CI 1.13–4.95), second stage of labour ≥ 120 min (OR 4.36; 95% CI 1.42–13.41), amniotic fluid pollution degree III (OR 10.39; 95% CI 3.30–32.73), and foetal weight ≥ 4000 g (OR 7.49; 95% CI 2.12–26.54). Based on clinical experience and previous studies, the duration of epidural labour analgesia also appeared to be a meaningful factor for intrapartum fever; therefore, these seven variables were used to develop a nomogram to predict intrapartum fever in parturients. The nomogram achieved a good area under the ROC curve of 0.86 and 0.81 in the training and in the validation cohorts, respectively. Additionally, the nomogram had a well-fitted calibration curve, which also showed excellent diagnostic performance.

Conclusion

We constructed a model to predict the occurrence of fever during childbirth and developed an accessible nomogram to help doctors assess the risk of fever during childbirth. Such assessment may be helpful in implementing reasonable treatment measures.

Trial registration

Clinical Trial Registration: (www.chictr.org.cnChiCTR2000035593)

Clinical chorioamnionitis at term X: microbiology, clinical signs, placental pathology, and neonatal bacteremia - implications for clinical care

OBJECTIVES

Clinical chorioamnionitis at term is considered the most common infection-related diagnosis in labor and delivery units worldwide. The syndrome affects 5-12% of all term pregnancies and is a leading cause of maternal morbidity and mortality as well as neonatal death and sepsis. The objectives of this study were to determine the (1) amniotic fluid microbiology using cultivation and molecular microbiologic techniques; (2) diagnostic accuracy of the clinical criteria used to identify patients with intra-amniotic infection; (3) relationship between acute inflammatory lesions of the placenta (maternal and fetal inflammatory responses) and amniotic fluid microbiology and inflammatory markers; and (4) frequency of neonatal bacteremia.

METHODS

This retrospective cross-sectional study included 43 women with the diagnosis of clinical chorioamnionitis at term. The presence of microorganisms in the amniotic cavity was determined through the analysis of amniotic fluid samples by cultivation for aerobes, anaerobes, and genital mycoplasmas. A broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry was also used to detect bacteria, select viruses, and fungi. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin-6 (IL-6) concentration ≥2.6 ng/mL.

RESULTS

(1) Intra-amniotic infection (defined as the combination of microorganisms detected in amniotic fluid and an elevated IL-6 concentration) was present in 63% (27/43) of cases; (2) the most common microorganisms found in the amniotic fluid samples were Ureaplasma species, followed by Gardnerella vaginalis; (3) sterile intra-amniotic inflammation (elevated IL-6 in amniotic fluid but without detectable microorganisms) was present in 5% (2/43) of cases; (4) 26% of patients with the diagnosis of clinical chorioamnionitis had no evidence of intra-amniotic infection or intra-amniotic inflammation; (5) intra-amniotic infection was more common when the membranes were ruptured than when they were intact (78% [21/27] vs. 38% [6/16]; p=0.01); (6) the traditional criteria for the diagnosis of clinical chorioamnionitis had poor diagnostic performance in identifying proven intra-amniotic infection (overall accuracy, 40-58%); (7) neonatal bacteremia was diagnosed in 4.9% (2/41) of cases; and (8) a fetal inflammatory response defined as the presence of severe acute funisitis was observed in 33% (9/27) of cases.

CONCLUSIONS

Clinical chorioamnionitis at term, a syndrome that can result from intra-amniotic infection, was diagnosed in approximately 63% of cases and sterile intra-amniotic inflammation in 5% of cases. However, a substantial number of patients had no evidence of intra-amniotic infection or intra-amniotic inflammation. Evidence of the fetal inflammatory response syndrome was frequently present, but microorganisms were detected in only 4.9% of cases based on cultures of aerobic and anaerobic bacteria in neonatal blood.

Association of lymphocyte count and incidence of maternal fever in epidural analgesia-involved labor

Background

Evidence showed that the use of epidural analgesia increased the risk of maternal fever during labor, and the potential mechanisms involved inflammation. Lymphocyte played a role in the inflammatory responses, and lymphopenia predicted adverse outcomes for patients. The aim of this study was to investigate whether lymphocyte count was associated with the incidence of intrapartum fever in nulliparous women undergoing vaginal delivery.

Methods

In this retrospective cohort study, electronic medical record data at the International Peace Maternity and Child Health Hospital (IPMCH, Shanghai, China) between 2012 and 2017 were extracted. The primary outcome of this study was baseline lymphocyte count in febrile and afebrile parturients who received labor epidural analgesia. Other confounding factors associated with the development of intrapartum fever were analyzed using multivariable logistic regression.

Results

The final study population consisted of 36,562 parturients, of whom 18,952 (51.8%) received labor epidural analgesia. Labor epidural analgesia was associated with an increased risk of maternal fever [relative risk: 4.55; 95% confidence interval (CI): 4.16–4.98; P<0.001]. Among the parturients who received epidural analgesia, both baseline lymphocyte count and lymphocyte percentage were lower in the febrile patients than those in the afebrile patients (P<0.001; P=0.015). The lower (<1.1×10⁹/L) baseline lymphocyte was associated with a higher risk of maternal fever (adjusted odds ratio: 1.30, 95% CI: 1.14–1.48; P<0.001).

Conclusions

Our results suggested that lower lymphocyte baseline indicated an increased risk of maternal fever during epidural analgesia-involved labor. Further studies are needed to confirm the findings and determine the potential mechanisms.

Diagnostic Validity of the Proposed Eunice Kennedy Shriver National Institute of Child Health and Human Development Criteria for Intrauterine Inflammation or Infection

OBJECTIVE

To investigate the test characteristics of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) criteria for intrauterine inflammation or infection or both (triple I) and rates of adverse outcomes in a cohort of febrile intrapartum women.

METHODS

This retrospective cohort study included women at 24 weeks of gestation or greater from June 2015 to September 2017 at a single tertiary hospital with a temperature 100.4°F or greater (38.0°C) during labor or within 1 hour postpartum, all of whom had blood culture data. Women with a fetal demise, expectantly managed preterm prelabor rupture of membranes, or nonobstetric infections were excluded. Documented fever was defined as a single temperature 102.2°F or greater (39.0°C) or a temperature 100.4°F or greater (38.0°C) but less than 102.2°F (39.0°C) on two measurements 45 minutes apart. We defined two analysis groups: 1) suspected triple I, defined as women with documented fever with clinical signs of infection; and 2) isolated maternal fever, defined as women with at least one temperature 100.4°F or greater (38.0°C) who did not meet criteria for suspected triple I. We assessed test characteristics of suspected triple I to predict 1) confirmed triple I, defined as suspected triple I with placental pathology diagnostic of infection; and 2) adverse clinical infectious outcome, defined as a composite of maternal and neonatal adverse infectious outcomes. We also calculated the incidence of adverse clinical infectious outcomes for both groups.

RESULTS

Three hundred thirty-nine women were analyzed: 212 with suspected triple I and 127 with isolated maternal fever. Baseline demographic and obstetric characteristics were similar between groups. The incidence of adverse clinical infectious outcomes was 11.8% among women with suspected triple I and 9.5% among women with isolated maternal fever (P=.50). The sensitivity and specificity of suspected triple I for confirmed triple I were 71.4% (95% CI 61.4-80.1%) and 40.5% (95% CI 33.6-47.8%), respectively, and for an adverse clinical infectious outcome were 67.6% (95% CI 50.2-82.0%) and 38.1% (95% CI 32.6-43.8%), respectively.

CONCLUSION

Applying the NICHD criteria to guide clinical diagnosis and management of intrauterine infection or inflammation may overlook an important proportion of laboring febrile women at risk for adverse infectious outcomes.

Ropivacaine at different concentrations on intrapartum fever, IL-6 and TNF-α in parturient with epidural labor analgesia

Effects of ropivacaine at different concentrations on intrapartum fever, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in parturient with epidural labor analgesia were compared to provide reference for the rational selection of anesthetics in clinic. Medical records of 198 cases of primi-paras admitted to the Obstetrics and Gynecology Department, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, from January 2017 to January 2018 were analyzed retrospectively and divided into 2 groups. A total of 105 patients were treated with 0.075% ropivacaine injection 10 ml and 0.5 µg/ml sulfentanyl injection 100 ml in parturition as the experimental group, and 93 patients were treated with 0.1% ropivacaine injection 10 ml and 0.5 µg/ml sulfentanyl injection 100 ml in parturition as the control group. After patient-controlled epidural analgesia, the pain visual analogue score (VAS), labor duration, administration time and febrile rate of parturient after administration were compared between the two groups at different time-points. Venous blood 2 ml was taken at T1 (cervix open to 2 cm), T2 (cervix fully open) and T3 (24 h postpartum), and the concentration of IL-6 TNF-α was detected by enzyme-linked immunosorbent assay. The time of the second stage of labor and analgesia were shorter in the experimental group than that in the control group after administration (P<0.05). The febrile rate of parturient in the experimental group was lower than that in the control group (P<0.05). The concentration of IL-6 and TNF-α in the experimental group was lower than that in the control group at T2 (P<0.05; P<0.01). The effect of patient-controlled epidural administration with 0.075% ropivacaine injection combined with 0.5 mg/ml sulfentanyl injection on labor analgesia is shorter than that with 0.1% ropivacaine combined with sulfentanyl. It could also shorten the duration of the second stage of labor, reduce the intrapartum febrile rate, and alleviate inflammation.

Risk Factors for Intrapartum Fever in Term Gestations and Associated Maternal and Neonatal Sequelae

AIM

To determine factors associated with intrapartum fever and to examine associated maternal and neonatal outcomes.

METHODS

Retrospective study of patients between 360/7 and 420/7 gestational weeks who entered spontaneous or induced active labor and developed temperature ≥38°C; a similar group that did not develop fever were controls. Univariate and multivariate analyses were performed with p < 0.05 as significant.

RESULTS

Fifty-four febrile patients and 306 nonfebrile controls met inclusion criteria. Nulligravidity (45.8 vs. 77.8%, p < 0.001), length of first stage ≥720 min (OR 3.59, 95% CI 1.97-6.55, p < 0.001), length of second stage ≥120 min (OR 4.76, 95% CI 2.29-9.89, p < 0.001), membrane rupture ≥240 min (46.4 vs. 79.6%, p < 0.001), increasing number of vaginal exams (4 vs. 6, p < 0.001), oxytocin (44.8 vs. 63.0%, p = 0.014), and meperidine (14.7 vs. 35.2%, p < 0.001) were all associated with intrapartum fever. Associated morbidity included cesarean delivery (22.5 vs. 44.4%, p = 0.001), Apgar score <7 at 5 min (0.7 vs. 5.6%, p = 0.011), and neonatal intensive care unit admission (9.5 vs. 51.9%, p < 0.001).

CONCLUSION

We have identified several noninfectious factors that are associated with intrapartum fever. Modification of risk factors may improve both maternal and neonatal outcomes.

Gene expression in term placentas is regulated more by spinal or epidural anesthesia than by late-onset preeclampsia or gestational diabetes mellitus

Pre-eclampsia (PE) and gestational diabetes mellitus (GDM) are common complications of pregnancy, but the mechanisms underlying these disorders remain unclear. The aim was to identify the extent of altered gene expression in term placentas from pregnant women with late-onset PE and GDM compared to controls. RNAseq identified few significantly differentially regulated genes in placental biopsies between PE, GDM, or uncomplicated pregnancy (n = 10 each group). Five genes were altered in placentas from PE including 4 non-coding genes and Angiopoietin 2 (ANGPT2). No genes were significantly regulated by GDM. In contrast, many genes were significantly regulated by fetal, maternal and delivery-specific variables, particularly spinal and epidural anesthesia. We selected ANGPT2 and Chemokine (C-X-C motif) ligand 14 (CXCL14) to test with qPCR in a larger set of placentas (n = 475) and found no differences between the groups. However, regression analysis revealed a stronger association between placental ANGPT2 and CXCL14 mRNA expression and fetal, maternal and delivery-specific variables than diagnostic group. To conclude, the gene expression in term placentas are highly affected by fetal, maternal and delivery specific variables. Few regulated genes were found in late-onset PE and GDM placentas, which may suggest that these conditions could be more affected by maternal factors.

Clinical chorioamnionitis at term IV: the maternal plasma cytokine profile

INTRODUCTION

Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentration: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that a fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response.

CONCLUSIONS

1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis.

Clinical chorioamnionitis at term III: how well do clinical criteria perform in the identification of proven intra-amniotic infection?

OBJECTIVE

The diagnosis of clinical chorioamnionitis is based on a combination of signs [fever, maternal or fetal tachycardia, foul-smelling amniotic fluid (AF), uterine tenderness and maternal leukocytosis]. Bacterial infections within the amniotic cavity are considered the most frequent cause of clinical chorioamnionitis and an indication for antibiotic administration to reduce maternal and neonatal morbidity. Recent studies show that only 54% of patients with the diagnosis of clinical chorioamnionitis at term have bacteria in the AF and evidence of intra-amniotic inflammation. The objective of this study was to examine the performance of the clinical criteria for the diagnosis of chorioamnionitis to identify patients with microbial-associated intra-amniotic inflammation (also termed intra-amniotic infection).

MATERIALS AND METHODS

This retrospective cross-sectional study included 45 patients with the diagnosis of clinical chorioamnionitis at term, whose AF underwent analysis for: 1) the presence of microorganisms using both cultivation and molecular biologic techniques [polymerase chain reaction (PCR) with broad primers], and 2) interleukin (IL)-6 concentrations by enzyme-linked immunosorbent assay. The diagnostic performance (sensitivity, specificity, accuracy, and likelihood ratios) of each clinical sign and their combination to identify clinical chorioamnionitis were determined using microbial-associated intra-amniotic inflammation [presence of microorganisms in the AF using cultivation or molecular techniques and elevated AF IL-6 concentrations (≥2.6 ng/mL)] as the gold standard.

RESULTS

The accuracy of each clinical sign for the identification of microbial-associated intra-amniotic inflammation (intra-amniotic infection) ranged between 46.7% and 57.8%. The combination of fever with three or more clinical criteria did not substantially improve diagnostic accuracy.

CONCLUSION

In the presence of a fever during labor at term, signs used to diagnose clinical chorioamnionitis do not accurately identify the patient with proven intra-amniotic infection (i.e., those with microorganisms detected by culture or molecular microbiologic techniques and an associated intra-amniotic inflammatory response).

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.

Clinical chorioamnionitis at term I: microbiology of the amniotic cavity using cultivation and molecular techniques

INTRODUCTION

The objectives of this study were: 1) to determine the amniotic fluid (AF) microbiology of patients with the diagnosis of clinical chorioamnionitis at term using both cultivation and molecular techniques; and 2) to examine the relationship between intra-amniotic inflammation with and without microorganisms and placental lesions consistent with acute AF infection.

METHODS

The AF samples obtained by transabdominal amniocentesis from 46 women with clinical signs of chorioamnionitis at term were analyzed using cultivation techniques (for aerobic and anerobic bacteria as well as genital mycoplasmas) and broad-range polymerase chain reaction (PCR) coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). The frequency of microbial invasion of the amniotic cavity (MIAC), intra-amniotic inflammation [defined as an AF interleukin 6 (IL-6) concentration ≥2.6 ng/mL], and placental lesions consistent with acute AF infection (acute histologic chorioamnionitis and/or acute funisitis) were examined according to the results of AF cultivation and PCR/ESI-MS as well as AF IL-6 concentrations.

RESULTS

1) Culture identified bacteria in AF from 46% (21/46) of the participants, whereas PCR/ESI-MS was positive for microorganisms in 59% (27/46) – combining these two tests, microorganisms were detected in 61% (28/46) of patients with clinical chorioamnionitis at term. Eight patients had discordant test results; one had a positive culture and negative PCR/ESI-MS result, whereas seven patients had positive PCR/ESI-MS results and negative cultures. 2) Ureaplasma urealyticum (n=8) and Gardnerella vaginalis (n=10) were the microorganisms most frequently identified by cultivation and PCR/ESI-MS, respectively. 3) When combining the results of AF culture, PCR/ESI-MS and AF IL-6 concentrations, 15% (7/46) of patients did not have intra-amniotic inflammation or infection, 6.5% (3/46) had only MIAC, 54% (25/46) had microbial-associated intra-amniotic inflammation, and 24% (11/46) had intra-amniotic inflammation without detectable microorganisms. 4) Placental lesions consistent with acute AF infection were significantly more frequent in patients with microbial-associated intra-amniotic inflammation than in those without intra-amniotic inflammation [70.8% (17/24) vs. 28.6% (2/7); P=0.04].

CONCLUSION

Microorganisms in the AF were identified in 61% of patients with clinical chorioamnionitis at term; 54% had microbial-associated intra-amniotic inflammation, whereas 24% had intra-amniotic inflammation without detectable microorganisms.

The association between epidural labor analgesia and maternal fever

The association between epidural labor analgesia and maternal fever is complex and controversial. Observational, retrospective, before-and-after, and randomized controlled trials all support the association, with the most current evidence supporting the mechanistic involvement of noninfectious inflammation. Considering the clinically significant neonatal consequences that have been previously demonstrated, and the possibility of more common subclinical fetal brain injury that animal models imply, the avoidance of maternal fever during labor is imperative. With the current popularity of epidural analgesia in labor, it is important that clinicians delineate how epidurals cause maternal fever and how to block the noninfectious inflammatory response that seems to warm a subset of women laboring with epidurals.