Labor epidural analgesia is independent risk factor for neonatal pyrexia

Epidural-related maternal fever: incidence, pathophysiology, outcomes, and management

Epidural-related maternal fever affects 15% to 25% of patients who receive a labor epidural. Two meta-analyses demonstrated that epidural-related maternal fever is a clinical phenomenon, which is unlikely to be caused by selection bias. All commonly used neuraxial techniques, local anesthetics with or without opioids, and maintenance regimens are associated with epidural-related maternal fever, however, the impact of each component is unknown. Two major theories surrounding epidural-related maternal fever development have been proposed. First, labor epidural analgesia may lead to the development of hyperthermia through a sterile (noninfectious) inflammatory process. This process may involve reduced activation of caspase-1 (a protease involved in cell apoptosis and activation of proinflammatory pathways) secondary to bupivacaine, which impairs the release of the antipyrogenic cytokine, interleukin-1-receptor antagonist, from circulating leucocytes. Detailed mechanistic processes of epidural-related maternal fever remain to be determined. Second, thermoregulatory mechanisms secondary to neuraxial blockade have been proposed, which may also contribute to epidural-related maternal fever development. Currently, there is no prophylactic strategy that can safely prevent epidural-related maternal fever from occurring nor can it easily be distinguished clinically from other causes of intrapartum fever, such as chorioamnionitis. Because intrapartum fever (of any etiology) is associated with adverse outcomes for both the mother and baby, it is important that all parturients who develop intrapartum fever are investigated and treated appropriately, irrespective of labor epidural utilization. Institution of treatment with appropriate antimicrobial therapy is recommended if an infectious cause of fever is suspected. There is currently insufficient evidence to warrant a change in recommendations regarding provision of labor epidural analgesia and the benefits of good quality labor analgesia must continue to be reiterated to expectant mothers.

Evaluation of Epidural Analgesia Use During Labor and Infection in Full-term Neonates Delivered Vaginally

IMPORTANCE

Quantification of potential consequences associated with the use of epidural analgesia during labor could help to improve the safety and quality of labor and delivery care for parturient women.

OBJECTIVE

To evaluate the association between epidural analgesia use during labor and neonatal infection in a large cohort of parturient women.

DESIGN, SETTING, AND PARTICIPANTS

This propensity score-matched cohort study was conducted at a university-affiliated hospital in Shanghai, China. Women at full-term pregnancy undergoing vaginal delivery between January 2013 and October 2018 were included in the study. Parturient women who were parous, experiencing premature delivery (gestational age <37 weeks), were pregnant with more than 1 fetus, or had experienced a stillbirth were excluded. Data were analyzed from October 2019 to June 2020.

EXPOSURES

The use of epidural analgesia during labor.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of neonatal infection, including neonatal sepsis, neonatal uncharacterized infection, neonatal pneumonia, and neonatal necrotizing enterocolitis reported in the medical record. Secondary outcomes included the incidence of maternal intrapartum fever and histologic chorioamnionitis.

RESULTS

Among 37 786 parturient women included (mean [SD] age, 29.5 [3.0] years), 19 968 (52.8%) received epidural analgesia during labor. In the propensity score-matched cohort (including 15 401 parturient women in each group), use of epidural analgesia was associated with a higher incidence of neonatal infection (absolute risk difference, 2.6%, 95% CI, 2.2%-3.0%; relative risk [RR], 2.43; 95% CI, 2.11-2.78), including higher incidence of sepsis (absolute risk difference, 0.1%, 95% CI, 0.1%-0.2%; RR, 3.50; 95% CI, 1.73-7.07) and uncharacterized infection (absolute risk difference, 2.2%, 95% CI, 1.9% to 2.6%; RR, 2.69; 95% CI, 2.30-3.15), compared with no epidural analgesia use. Use of epidural analgesia was also associated with greater incidence of maternal intrapartum fever (RR, 4.12; 95% CI, 3.78-4.50) and histologic chorioamnionitis (RR, 4.08; 95% CI, 3.59-4.64) compared with no epidural analgesia use.

CONCLUSIONS AND RELEVANCE

This cohort study found that use of epidural analgesia in full-term nulliparous women undergoing vaginal delivery was associated with an increased risk of neonatal infection, pending further investigation. These findings support efforts to further improve safety and quality of labor and delivery care for parturient women.

Epidural analgesia, intrapartum hyperthermia, and neonatal brain injury: a systematic review and meta-analysis

BACKGROUND

Epidural analgesia is associated with intrapartum hyperthermia, and chorioamnionitis is associated with neonatal brain injury. However, it is not known if epidural hyperthermia is associated with neonatal brain injury. This systematic review and meta-analysis investigated three questions: (1) does epidural analgesia cause intrapartum hyperthermia, (2) is intrapartum hyperthermia associated with neonatal brain injury, and (3) is epidural-induced hyperthermia associated with neonatal brain injury?

METHODS

PubMed, ISI Web of Knowledge, The Cochrane Library, and Embase were searched from inception to January 2020 using Medical Subject Headings (MeSH) terms relating to epidural analgesia, hyperthermia, labour, and neonatal brain injury. Studies were reviewed independently for inclusion and quality by two authors (Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach). Two meta-analyses were performed using the Mantel-Haenszel fixed effect method to generate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Forty-one studies were included for Question 1 (646 296 participants), 36 for Question 2 (11 866 021 participants), and two studies for Question 3 (297 113 participants). When the mode of analgesia was randomised, epidural analgesia was associated with intrapartum hyperthermia (OR: 4.21; 95% CI: 3.48-5.09). There was an association between intrapartum hyperthermia and neonatal brain injury (OR: 2.79; 95% CI: 2.54-2.3.06). It was not possible to quantify the association between epidural-induced hyperthermia and neonatal brain injury.

CONCLUSIONS

Epidural analgesia is a cause of intrapartum hyperthermia, and intrapartum hyperthermia of any cause is associated with neonatal brain injury. Further work is required to establish if epidural-induced hyperthermia is a cause of neonatal brain injury.

Does the presence of epidural analgesia reduce the risk of neonatal sepsis in the setting of an intrapartum fever?

Objective: Epidural analgesia has been associated with more frequent intrapartum fever as well as neonatal antibiotic therapy. We examined whether intrapartum fever carries the same risk for neonatal sepsis with and without epidural.Methods: This is a retrospective cohort study of 34,371 deliveries at a single institution. Primary outcome variables included neonatal sepsis, Apgar scores, neonatal intensive care (NICU) admission, postpartum hemorrhage, prolonged labor, and cesarean delivery. Univariate analysis and multivariable logistic regression were used to assess the risk of sepsis while controlling for possible confounding covariables.Results: A total of 34,371 patients were included in the study, 16,917 (49.9%) of whom had epidural anesthesia. Of the patients who had an epidural, 2103 (12.4%) had an intrapartum fever, compared to 446 (2.6%) of those who did not have an epidural (p < .001). Overall, there was a decreased risk of neonatal sepsis in the setting of intrapartum fever with an epidural after controlling for potential confounders. (aOR 0.53 [95% CI 0.29-0.98]). In preterm patients, an epidural was associated with a decreased risk for neonatal sepsis (5.7% vs. 10.0%, p = .04), 5-minute Apgar score <7 (23.5% vs. 33.6%, p = .006), and NICU admission (66.6% vs. 76.5%, p = .008) compared to those born in the setting of a fever without an epidural.Conclusions: Neonates were less likely to sustain a diagnosis of sepsis in the setting of an epidural-associated fever compared to those in the setting of an intrapartum fever without an epidural. These data may be used by providers in counseling and guideline creation.

Effects of Labor Epidural Analgesia on Short Term Neonatal Morbidity

Background

Epidural Analgesia (EA) is the most effective and most commonly used method for pain relief during labor. Some researchers have observed an association between EA and increased neonatal morbidity. But this observation was not consistent in many other studies.

Objectives

The primary objective of the study was to examine whether exposure to epidural analgesia increased the risk of NICU admission. The secondary objectives included the risks of clinical chorioamnionitis, instrumental delivery, neonatal depression, respiratory distress, birth trauma, and neonatal seizure during the first 24 hours of life.

Methods

This was a retrospective cohort study involving 2360 low-risk nulliparous women who delivered at AWH, Qatar, during the two years between January 2016 December and 2017. Short-term neonatal outcomes of the mothers who received EA in active labor were compared with a similar population who did not receive EA. As secondary objectives, labor parameters like maternal temperature elevation, duration of the second stage of labor, and instrumental delivery were compared.

Results

Significantly higher numbers of neonates were admitted to the NICU from the EA group (P<0.001, OR 1.89, 95% CI 1.45 to 2.46). They were more likely to have respiratory distress (P=0.01, OR 1.49, 95% CI 1.07 to 2.07), birth injuries (P=0.02, OR =1.71, 95% CI 1.06 to 2.74), admission temperature>37.5 °C (P=0.04, OR 3.40, 95% CI 1.00 to 11.49), need for oxygen on the first day (P=0.04, OR 1.44, 95% CI 1.01 to 2.07) and receive antibiotics (P<0.001, OR 2.06,95% CI 1.47 to 2.79). There was no difference in the Apgar score at 1 minute (P=0.12), need of resuscitation at birth (P=0.05), neonatal white cell count (P=0.34), platelet count (P=0.38) and C reactive protein (P=0.84). Mothers who received EA had a lengthier second stage (P<0.001), temperature elevation >37.5°C (P<0.001, OR 7.40, 95% CI 3.93 to 13.69) and instrumental delivery (P<0.001, OR 2.13, 95% CI 1.69 to 2.68).

Conclusion

EA increases NICU admission, antibiotic exposure, neonatal birth injuries, need for positive pressure ventilation at birth, and respiratory distress in the first 24 hours of life. Mothers on epidural analgesia have prolonged second stage of labor, a higher rate of instrumental delivery, meconium-stained amniotic fluid, fetal distress, and temperature elevation.

Epidural Labor Analgesia and Maternal Fever

Women receiving an epidural for labor analgesia are at increased risk for intrapartum fever. This relationship has been supported by observational, before and after, and randomized controlled trials. The etiology is not well understood but is likely a result of noninfectious inflammation as studies have found women with fever have higher levels of inflammatory markers. Maternal pyrexia may change obstetric management and women are more likely to receive antibiotics or undergo cesarean delivery. Maternal pyrexia is associated with adverse neonatal outcomes. With these consequences, understanding and preventing maternal fever is imperative.

Effects of local anesthetics on the respiratory burst of cord blood neutrophils in vitro

BACKGROUND

Whether local anesthetics exert anti-inflammatory effects in fetal and newborn systemic neutrophils is unclear. The aim of the present study was to assess the effects of bupivacaine and lidocaine on the respiratory burst of cord blood neutrophils in vitro compared with adult cells.

METHODS

Whole cord blood (n = 12) and control adult blood samples (n = 7) were incubated with bupivacaine (0.0005, 0.005, 0.05, 1 mmol/l) and lidocaine (0.002, 0.02, 0.2, 4 mmol/l) for 1 and 4 h. The production of reactive oxygen species (ROS) by unstimulated neutrophils and the phorbol myristate acetate-induced oxidative burst were assessed by flow cytometry. A subset of neutrophils showing high fluorescence intensity (rho+) was analyzed separately.

RESULTS

After 1 h incubation, local anesthetics decreased the respiratory burst in whole cord blood and adult neutrophils in a similar manner. At the clinically relevant concentration of 0.0005 mmol/l, bupivacaine was active, but its effect in cord blood cells could not be detected after 4 h. The cord blood rho+ cell subset was unresponsive to the inhibitory action of bupivacaine. In rho+ neutrophils, basal ROS production was stimulated by lidocaine at the lowest concentration tested.

CONCLUSION

Bupivacaine and lidocaine can decrease the respiratory burst in neutrophils of term newborns.

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).

Low Apgar score, neonatal encephalopathy and epidural analgesia during labour: a Swedish registry-based study

BACKGROUND

Maternal intrapartum fever (MF) is associated with neonatal sequelae, and women in labour who receive epidural analgesia (EA) are more likely to develop hyperthermia. The aims of this study were to investigate if EA and/or a diagnosis of MF were associated to adverse neonatal outcomes at a population level.

METHODS

Population-based register study with data from the Swedish Birth Register and the Swedish National Patient Register, including all nulliparae (n=294,329) with singleton pregnancies who gave birth at term in Sweden 1999-2008. Neonatal outcomes analysed were Apgar score (AS)<7 at 5 min and ICD-10 diagnosis of neonatal encephalopathy (e.g. convulsions or neonatal cerebral ischaemia). Multivariate logistic regression was used to calculate adjusted odds ratios (AOR) with 95% confidence intervals (CI).

RESULTS

EA was used in 44% of the deliveries. Low AS or encephalopathy was found in 1.26% and 0.39% of the children in the EA group compared with 0.80% and 0.29% in the control group. In multivariate analysis, EA was associated with increased risk with low AS, AOR 1.27 (95% CI 1.16-1.39), but not with diagnosis of encephalopathy, 1.11 (0.96-1.29). A diagnosis of MF was associated with increased risk for both low AS, 2.27 (1.71-3.02), and of neonatal encephalopathy, 1.97 (1.19-3.26).

CONCLUSION

Diagnosis of MF was associated with low AS and neonatal encephalopathy, whereas EA was only associated with low AS and not with neonatal encephalopathy. The found associations might be a result of confounding by indication, which is difficult to assess in a registry-based population study.

2010 perinatal GBS prevention guideline and resource utilization

OBJECTIVES

To quantify differences in early-onset sepsis (EOS) evaluations, evaluation-associated resource utilization, and EOS cases detected, when comparing time periods before and after the implementation of an EOS algorithm based on the Centers for Disease Control and Prevention (CDC) 2010 guidelines for prevention of perinatal Group B Streptococcus (GBS) disease.

METHODS

Retrospective cohort study of infants born at ≥36 weeks' gestation from 2009 to 2012 in a single tertiary care center. One 12-month period during which EOS evaluations were based on the CDC 2002 guideline was compared with a second 12-month period during which EOS evaluations were based on the CDC 2010 guideline. A cost minimization analysis was performed to determine the EOS evaluation-associated costs and resources during each time period.

RESULTS

During the study periods, among well-appearing infants ≥36 weeks' gestation, EOS evaluations for inadequate GBS prophylaxis decreased from 32/1000 to <1/1000 live births; EOS evaluation-associated costs decreased by $6994 per 1000 live births; and EOS evaluation-associated work hours decreased by 29 per 1000 live births. We found no increase in EOS evaluations for other indications, total NICU admissions, frequency of infants evaluated for symptoms before hospital discharge, or incidence of EOS during the 2 study periods.

CONCLUSIONS

Implementation of an EOS algorithm based on CDC 2010 GBS guidelines resulted in a 25% decrease in EOS evaluations performed among well-appearing infants ≥36 weeks' gestation, attributable to decreased evaluation of infants born in the setting of inadequate indicated GBS prophylaxis. This resulted in significant changes in EOS evaluation-associated resource expenditures.

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.