Outcomes associated with antibiotic administration for isolated maternal fever in labor

Intrapartum fever complicated with maternal bacteremia: prevalence, bacteriology, and risk factors

PURPOSE

To assess the prevalence, microbial profile, and clinical risk factors of maternal bacteremia associated with intrapartum fever (IPF).

METHODS

A retrospective cohort study, in a single tertiary university-affiliated medical center between 2012 and 2018. Demographic and labor characteristics of women, who delivered at term (37+0/7-41+6/7) and developed bacteremia following IPF were compared to a control group of women with IPF but without bacteremia.

RESULTS

During the study period there were 86,590 deliveries in our center. Of them, 2074 women (2.4%) were diagnosed with IPF, of them, for 2052 women (98.93%) the blood maternal cultures were available. In 26 patients (1.25%) maternal bacteremia was diagnosed. A lower rate of epidural anesthesia (84.6% vs 95.9%, p = 0.02) and a higher rate of antibiotics prophylaxis treatment prior to the onset of fever (30.8%.vs 12.1%, p = 0.006) were observed in patients who developed maternal bacteremia in comparison to those who have not. Maternal hyperpyrexia developed after initiation of antibiotics or without epidural anesthesia remained significantly associated with maternal bacteremia after applying a multivariate analysis, (Odds Ratio 3.14 95% CI 1.27-7.14, p = 0.009; 4.76 95% CI 1.35-12.5, p = 0.006; respectively).

CONCLUSION

Maternal fever developing after initiation of antibiotics or without epidural is associated with maternal bacteremia.

Characteristics and Management of Chorioamnionitis at an Academic Centre in Ontario Before and After Implementation of an Order Set

OBJECTIVES

Chorioamnionitis has implications for parturient and neonatal outcomes but is difficult to diagnose accurately. The particulars of management also differ between providers and between institutions. Clinical order sets have been shown to standardize and improve care. This study compares characteristics of chorioamnionitis and aspects of management before and after implementation of an order set.

METHODS

Chart review facilitated comparison of 76 cases occurring prior to implementation of the order set and 66 cases occurring after. Characteristics of chorioamnionitis used for diagnosis and particulars of management were assessed.

RESULTS

There was no significant difference in baseline characteristics between the groups. Parturient tachycardia was more prevalent in cases occurring after implementation of the order set but there was no difference in the percentage of cases meeting Gibb's criteria. Management of cases pre- and post-implementation of the order set differed only in antibiotic choice. Percentage of cases with blood cultures or placental examination performed did not differ.

CONCLUSIONS

Overall, implementation of the order set did not significantly impact diagnosis of chorioamnionitis and altered management only with respect to antibiotic choice.

Performance Characteristics of Sepsis Screening Tools During Delivery Admissions

OBJECTIVE

To evaluate the screening performance characteristics of existing tools for the diagnosis of sepsis during delivery admissions.

METHODS

This was a case-control study using electronic health record data, including vital signs and laboratory results, for all delivery admissions of patients with sepsis from 59 nationally distributed hospitals. Patients with sepsis were matched by gestational age at delivery in a 1:4 ratio with patients without sepsis to create a comparison group. Patients with chorioamnionitis and sepsis were compared with a complete cohort of patients with chorioamnionitis without sepsis. Multiple screening criteria for sepsis were evaluated: the CMQCC (California Maternal Quality Care Collaborative), SIRS (Systemic Inflammatory Response Syndrome), the MEWC (the Maternal Early Warning Criteria), UKOSS (United Kingdom Obstetric Surveillance System), and the MEWT (Maternal Early Warning Trigger Tool). Sensitivity, false-positive rates, and C-statistics were reported for each screening tool. Analyses were stratified into cohort 1, which excluded patients with chorioamnionitis-endometritis, and cohort 2, which included those patients.

RESULTS

Delivery admissions at 59 hospitals were extracted for patients with sepsis. Cohort 1 comprised 647 patients with sepsis, including 228 with end-organ injury, matched with a control group of 2,588 patients without sepsis. Cohort 2 comprised 14,591 patients with chorioamnionitis-endometritis, of whom 1,049 had sepsis and 238 had end-organ injury. In cohort 1, the CMQCC and the UKOSS pregnancy-adjusted criteria had the lowest false-positive rates (6.9% and 9.6%, respectively) and the highest C-statistics (0.92 and 0.91, respectively). Although other screening criteria, such as SIRS and the MEWC, had similar sensitivities, it was at the cost of much higher false-positive rates (21.3% and 38.3%, respectively). In cohort 2, including all patients with chorioamnionitis-endometritis, the highest C-statistics were again for the CMQCC (0.67) and UKOSS (0.64). All screening tools had high false-positive rates, but the false-positive rates for the CMQCC and UKOSS were substantially lower than those for SIRS and the MEWC.

CONCLUSION

During delivery admissions, the CMQCC and UKOSS pregnancy-adjusted screening criteria have the lowest false-positive results while maintaining greater than 90% sensitivity rates. Performance of all screening tools was degraded in the setting of chorioamnionitis-endometritis.

Antibiotic treatment of women with isolated intrapartum fever vs clinical chorioamnionitis: maternal and neonatal outcomes

BACKGROUND

Clinical chorioamnionitis refers to the presence of maternal fever (≥38°C) and at least 2 clinical signs: (1) maternal tachycardia (>100 bpm), (2) fetal tachycardia (>160 bpm), (3) maternal leukocytosis >15,000/mm2, (4) purulent vaginal discharge, and (5) uterine tenderness. Few data exist to guide the appropriate management of women with isolated intrapartum fever in the absence of other clinical signs suggesting chorioamnionitis.

OBJECTIVE

This study compared maternal and neonatal infectious outcomes and microbiological outcomes between women with isolated intrapartum fever and women with clinical chorioamnionitis.

STUDY DESIGN

This 10-year retrospective study included all the laboring women at our institution, at ≥34 weeks of gestation, with a singleton pregnancy and body temperature of ≥38.0°C, with or without other evidences of infection. According to our department protocol, women with isolated intrapartum fever received intravenous ampicillin, whereas women with clinical chorioamnionitis received intravenous ampicillin plus gentamicin. The primary outcome was puerperal endometritis, compared between women with isolated intrapartum fever (treated with ampicillin) and women with clinical chorioamnionitis (treated with ampicillin plus gentamicin). The secondary maternal outcomes consisted of (1) maternal clinical outcomes, such as cesarean delivery, surgical site infection, postpartum hemorrhage, and postpartum length of stay, and (2) microbiological studies, including positive chorioamniotic membrane swabs and blood culture. Among the secondary neonatal outcomes were early-onset sepsis, neonatal intensive care unit admission, and length of stay. Of note, 2 multivariate logistic regression models were created. A model aimed to predict puerperal endometritis controlled for gestational age of >41 weeks, diabetes mellitus, obesity, positive group B streptococcus status, rupture of membrane ≥18 hours, meconium staining, positive chorioamniotic membrane swabs, cesarean delivery, and empiric postdelivery antibiotic administration. A model aimed to predict neonatal early-onset sepsis controlled for gestational age of 34 to 37 weeks, positive group B streptococcus status, rupture of membrane ≥18 hours, and positive chorioamniotic membrane swabs.

RESULTS

Overall, 458 women met the inclusion criteria. Compared with women with clinical chorioamnionitis (n=231), women with isolated intrapartum fever (n=227) had higher rates of puerperal endometritis (3.9% vs 8.8%; P=.03), early-onset sepsis (0.4% vs 4.4%; P=.005), positive chorioamniotic membrane swabs (46.3% vs 63.9%; P<.001), and ampicillin-resistant Escherichia coli (35.5% vs 48.9%; P=.033). The rate of group B streptococcus-positive chorioamniotic membrane swabs was similar between the groups. In a subanalysis of women with negative or unknown group B streptococcus status, the puerperal endometritis and neonatal early-onset sepsis rates were higher among women with isolated intrapartum fever than women with suspected chorioamnionitis (8.7% vs 3.3% [P=.041] and 4.1% vs 0% [P<.001], respectively). In 2 multivariate analysis models, among women with isolated intrapartum fever treated with ampicillin compared with those with clinical chorioamnionitis treated with ampicillin and gentamicin, the odds ratio of antibiotic treatment of endometritis was 2.65 (95% confidence interval, 1.06-6.62; P=.036), and the odds ratio of neonatal early-onset sepsis was 8.33 (95% confidence interval, 1.04-60.60; P=.045).

CONCLUSION

Women with intrapartum fever, with or without other signs of infection, were at increased risk of maternal and neonatal complications. The use of ampicillin as a sole agent in isolated intrapartum fever might promote ampicillin-resistant E coli growth in the chorioamniotic membranes and consequently lead to puerperal endometritis and early-onset sepsis. In this context, a broad-range antibiotic should be considered.

Single versus dual antibiotic regimen in women with term prolonged rupture of membranes and intrapartum fever: a retrospective study

OBJECTIVES

The impact of E. coli in causing peripartum infections has been increasing due to rising ampicillin resistance. In this study, we compared maternal and neonatal outcomes of women with prolonged rupture of membranes (ROM >18h) and intrapartum fever, according to two antibiotic regimens they received, and describe the bacterial distribution focusing on risk factors for Enterobacteriaceae-related infectious morbidity.

STUDY DESIGN

This 10-year retrospective study of women with ROM >18h and intrapartum fever included 62 women who were treated with ampicillin and gentamicin due to suspected intraamniotic infection and 79 without these signs who were treated with ampicillin alone. The primary outcomes were endometritis and neonatal early-onset sepsis (EOS) rates. Outcomes were compared using univariate and multivariate analyses.

RESULTS

Among women who received ampicillin alone compared with dual therapy, rates were higher of endometritis (17% vs. 3%, p<0.001), neonatal early onset sepsis (7.5% vs. 0%, p=0.03), Enterobacteriaceae positive placental swab culture (67.9% vs. 15.7%, p<0.001), and histopathological subchorionitis (25.3% vs. 8.0%, p=0.008). Over 83% of Enterobacteriaceae isolates were ampicillin-resistant. Gestational age at delivery >41 weeks, meconium at delivery, ROM >24h and treatment with a single antibiotic agent were associated with the presence of a positive Enterobacteriaceae placental swab culture.

CONCLUSION

Ampicillin compared to dual treatment in women with prolonged ROM and fever might promote the growth of ampicillin-resistant Enterobacteriaceae (including E.coli) and increase risks of maternal and neonatal infectious morbidity.

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.

Maternal fever in labor: etiologies, consequences, and clinical management

Intrapartum fever is common and presents diagnostic and treatment dilemmas for the clinician. True maternal sepsis is rare; only an estimated 1.4% of women with clinical chorioamnionitis at term develop severe sepsis. However, the combination of inflammation and hyperthermia adversely impacts uterine contractility and, in turn, increases the risk for cesarean delivery and postpartum hemorrhage by 2- to 3-fold. For the neonate, the rates of encephalopathy or the need for therapeutic hypothermia have been reported to be higher with a maternal fever >39°C when compared with a temperature of 38°C to 39°C (1.1 vs 4.4%; P<.01). In a large cohort study, the combination of intrapartum fever and fetal acidosis was particularly detrimental. This suggests that intrapartum fever may lower the threshold for fetal hypoxic brain injury. Because fetal hypoxia is often difficult to predict or prevent, every effort should be made to reduce the risk for intrapartum fever. The duration of exposure to epidural analgesia and the length of labor in unmedicated women remain significant risk factors for intrapartum fever. Therefore, paying careful attention to maintaining labor progress can potentially reduce the rates of intrapartum fever and the risk for cesarean delivery if fever does occur. A recent, double-blind randomized trial of nulliparas at >36 weeks' gestation demonstrated that a high-dose oxytocin regimen (6×6 mU/min) when compared with a low-dose oxytocin regimen (2×2 mU/min) led to clinically meaningful reductions in the rate of intrapartum fever (10.4% vs 15.6%; risk rate, 0.67; 95% confidence interval, 0.48-0.92). When fever does occur, antibiotic treatment should be initiated promptly; acetaminophen may not be effective in reducing the maternal temperature. There is no evidence that reducing the duration of fetal exposure to intrapartum fever prevents known adverse neonatal outcomes. Therefore, intrapartum fever is not an indication for cesarean delivery to interrupt labor with the purpose of improving neonatal outcome. Finally, clinicians should be ready for the increased risk for postpartum hemorrhage and have uterotonic agents on hand at delivery to prevent delays in treatment.

Rectovaginal Colonization with Serotypes of Group B Streptococci with Reduced Penicillin Susceptibility among Pregnant Women in León, Nicaragua

Group B Streptococci (GBS) are important causes of neonatal sepsis and meningitis globally. To elucidate the potential benefits of maternal GBS vaccines, data is needed on the epidemiology of maternal GBS rectovaginal colonization, distribution of serotypes, and resistance to intrapartum antibiotic prophylaxis (IAP). We collected rectal and vaginal samples from 305 pregnant women in León, Nicaragua between 35 and 40 weeks gestation. Samples were cultured for GBS and confirmed using latex agglutination. GBS isolates underwent serotyping by quantitative polymerase chain reaction, and antimicrobial susceptibility testing by disk diffusion and microdilution following Clinical Laboratory Standard Institute guidelines. Sixty-three women (20.7%) were colonized with GBS in either the rectum or the vagina. Of 91 GBS isolates collected from positive cultures, most were serotypes II (28.6%), Ia (27.5%), and III (20.9%). Most GBS isolates (52.9%) were resistant to penicillin, the first-line prophylactic antibiotic. Penicillin resistance was highly correlated with resistance to vancomycin, ceftriaxone, and meropenem. The results of our study suggest that one-fifth of pregnant women in the urban area of León, Nicaragua are colonized with GBS and risk transmitting GBS to their offspring during labor. High resistance to commonly available antibiotics in the region suggests that prophylactic maternal GBS vaccination would be an effective alternative to IAP.