Severity of intrapartum fever and neonatal outcomes

Development and validation of a machine learning model for predicting intrapartum fever using pre-labor analgesia clinical indicators: a multicenter retrospective study

BACKGROUND

Labor anesthesia is commonly used for pain relief during labor, but it can increase the risk of intrapartum fever. Currently, there are no reliable tools to predict which parturients might develop fever before labor anesthesia. The prediction model we developed aims to predict the incidence of intrapartum fever before labor analgesia.

METHODS

This study retrospectively analyzed the clinical data of parturients who underwent labor analgesia at Chengdu Jinjiang District Maternal & Child Health Hospital and Sichuan Jinxin Xinan Women's & Children's Hospital from January 2021 to June 2023. After the data were processed, the parturients were randomly divided into training and validation cohorts at an 8:2 ratio. The least absolute shrinkage and selection operator method was used for feature selection. Six machine learning models were developed and subjected to comprehensive analysis to assess and validate their predictive capabilities, ultimately selecting the best-performing model.

RESULTS

The study included a total of 5,052 parturients, with 418 (8.27%) parturients experiencing intrapartum fever. The predictive factors were primiparity, estimated neonatal weight, degree of uterine dilatation, presence of anemia, number of vaginal examinations, and height. The multilayer perceptron model emerged as the best-performing predictive model, achieving an area under the curve of 0.707, a sensitivity of 0.753, and a specificity of 0.584.

CONCLUSIONS

The multilayer perceptron model, utilizing readily available pre-labor analgesia variables, demonstrates potential for predicting intrapartum fever. In comparison to existing tools, this model may enable earlier identification of high-risk parturients, supporting timely interventions and potentially enhancing maternal and neonatal health outcomes.

Predictive value of the neutrophil-to-lymphocyte ratio for epidural labor analgesia-associated intrapartum fever: a retrospective single-center study

BACKGROUND

Studies have indicated that epidural analgesia increases the risk of maternal fever during labor, possibly due to non-infectious inflammation. The neutrophil-to-lymphocyte ratio (NLR) is a crucial indicator of inflammation, with a higher NLR potentially signaling worse patient adverse outcomes. The present study explores whether NLR has clinical predictive value for epidural analgesia-related maternal fever (ERMF).

METHODS

A retrospective analysis was performed for 1602 women who voluntarily requested analgesia for epidural labor from January 2023 to June 2024. Univariate and multivariate logistic regression analyses were applied to identify the factors influencing intrapartum fever, and the association between NLR and ERMF was explored. The receiver operating characteristic (ROC) curve was used to assess the area under the curve (AUC) of NLR for intrapartum fever, and the nearest ascending index was utilized to determine the cut-off value.

RESULTS

A total of 1602 parturients were included, of which 160 (10%) had intrapartum fever. Body mass index (BMI) (OR = 1.132, 95% CI: 1.027-1.246, P = 0.012), the duration of the first stage of labor (OR = 1.002, 95% CI: 1.001-1.003, P < 0.001), percentage of lymphocytes (OR = 1.205, 95%CI: 1.073-1.354, P = 0.012) and NLR (OR = 1.964, 95% CI: 1.462-2.639, P < 0.001) were independent risk factors for intrapartum fever. High NLR levels were associated with a higher incidence of ERMF at subgroups of ages < 35 years (OR = 1.343, 95%CI: 1.215-1.486, P < 0.001), ages ≥ 35 years (OR = 1.274, 95%CI: 1.105-1.468, P = 0.01), BMI < 24 kg/m2 (OR = 1.326, 95% CI: 1.176-1.495, P < 0.001), BMI ≥ 24 kg/m2 (OR = 1.515, 95%CI: 1.147-2.000, P = 0.003), first stage of labor < 600 min (OR = 1.466, 95%CI: 1.241-1.733, P < 0.001), and first stage of labor ≥ 600 min (OR = 1.257, 95%CI: 1.109-1.424, P < 0.001). Maternal NLR levels greater than 6.305 (AUC = 0.702, 95%CI: 0.634-0.768, P < 0.001) were good predicators of intrapartum fever.

CONCLUSIONS

High NLR is associated with EMRF, and NLR is a viable predictor of early identification of the occurrence of EMRF, which may be beneficial for pregnancy outcomes.

Impact and Contributing Factors of Maternal Pyrexia Peaks During Labor on Maternal and Neonatal Outcomes

This study aims to equip clinicians with the necessary insights for identifying and managing pregnant women experiencing elevated maternal pyrexia during labor. It examines maternal and neonatal outcomes along with the factors associated with varying peak temperatures. A retrospective analysis was conducted on 319 pregnant women presenting with maternal pyrexia during labor. Participants were categorized into two groups based on peak temperature: Group A (n = 180, temperature <38°C) and Group B (n = 139, temperature ≥38°C). Basic characteristics, blood markers, and maternal and neonatal outcomes were compared between the two groups. (1) Group B exhibited a higher percentage of neutrophilic granulocytes (NE%) and C-reactive protein to lymphocyte ratio (CLR) compared with Group A (p < 0.05). (2) The rates of meconium-stained amniotic fluid, histological chorioamnionitis, hospitalization of neonates, and infections in neonates were greater in Group B than in Group A (p < 0.05). (3) Logistic regression analysis identified elevated CLR levels as a risk factor for peak temperatures exceeding 38°C, indicating that CLR could serve as a reliable predictor of maternal pyrexia above 38°C during labor. Higher maternal pyrexia peaks may exacerbate adverse maternal and neonatal outcomes, emphasizing the importance of timely clinical intervention. NE% and CLR could serve as valuable indicators for identifying underlying causes and predicting peak maternal pyrexia during labor.

Predictive value of neutrophil-to-lymphocyte ratio on admission for intrapartum maternal fever in parturients undergoing epidural analgesia: A retrospective cohort study using propensity score-matched analysis

OBJECTIVE

To identify the predictive value of the neutrophil-to-lymphocyte ratio (NLR) on admission for intrapartum maternal fever in parturients undergoing epidural analgesia (EA).

METHODS

In this retrospective cohort study, propensity score matching (PSM) was applied to address covariates. Univariate and multivariate regression analyses were implemented in sequence to find out the factors influencing intrapartum fever. The receiver operating characteristics curve was applied to determine the area under the curve (AUC) of NLR for intrapartum fever.

RESULTS

NLR and duration of EA were independent risk factors for intrapartum fever. The AUC of the combined indicator (NLR + duration of EA) was higher than that of NLR (AUC = 0.583, 95% confidence interval [CI] 0.53-0.64) and duration of EA (AUC = 0.702, 95% CI 0.66-0.75), reaching 0.715 (95% CI 0.67-0.76; p < 0.001). NLR increased predictive performance for intrapartum fever when added to the duration of EA (net reclassification index 0.076, p = 0.022; integrated discrimination improvement 0.020, p = 0.002).

CONCLUSION

NLR has limited predictive power for intrapartum fever. The combination of NLR and duration of epidural analgesia may be considered a promising predictor for intrapartum maternal fever in parturients undergoing epidural analgesia.

SYNOPSIS

The neutrophil-to-lymphocyte ratio is an accessible predictor for the early identification of parturients at risk of intrapartum fever.

Association between neutrophil-to-lymphocyte ratio and epidural-related maternal fever in Chinese parturients: a prospective cohort study

OBJECTIVE

Epidural analgesia could increase the risk of maternal fever during labor, and the potential mechanisms involved inflammation. Neutrophil-to-lymphocyte ratio (NLR) was a sensitive inflammatory composite indicator and related to adverse outcomes in parturients. This study aimed to investigate the association between NLR levels and epidural related maternal fever (ERMF).

METHODS

This prospective cohort study included 614 parturients who underwent epidural analgesia at the Women's Hospital School of Medicine Zhejiang University from November 2021 to May 2023. NLR level was calculated before epidural analgesia for women. The outcome was ERMF. Univariate and multivariate logistic regression models were utilized to explore the association between NLR level and ERMF. And the association was further investigated in subgroups of age, body mass index (BMI) before pregnancy, and parity of delivery. The results were presented as odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Totally, 614 parturients, of whom 171 (27.85%) had ERMF. High NLR level was associated with higher incidence of ERMF (OR = 2.70, 95% CI: 1.58-4.69). Parturients with ERMF had higher proportion of postpartum hemorrhage, longer labor times, and other adverse outcomes in parturients. The association also observed in subgroups of age <35 years old (OR = 2.74, 95% CI: 1.55-4.29), BMI <24 kg/m2 before pregnancy (OR = 2.32, 95% CI: 1.32-4.13), BMI ≥24 kg/m2 before pregnancy (OR = 38.28, 95%CI: 3.67-854.66), primipara (OR = 2.26, 95% CI:1.27-4.04), and multipara (OR = 30.60, 95% CI: 3.73-734.03).

CONCLUSION

High NLR levels were associated with ERMF in women. It indicated that physicians may measure NLR levels as a regular measurement, which may beneficial for pregnancy outcomes.

Impact of postpartum maternal fever or hypothermia on newborn and early infant illness and death in Southwestern Uganda

BACKGROUND

Deaths occurring during the neonatal period contribute close to half of under-five mortality rate (U5MR); over 80% of these deaths occur in low- and middle-income countries (LMICs). Poor maternal antepartum and perinatal health predisposes newborns to low birth weight (LBW), birth asphyxia, and infections which increase the newborn's risk of death.

METHODS

The objective of the study was to assess the association between abnormal postpartum maternal temperature and early infant outcomes, specifically illness requiring hospitalisation or leading to death between birth and six weeks' age. We prospectively studied a cohort of neonates born at Mbarara Regional Referral Hospital in Uganda to mothers with abnormal postpartum temperature and followed them longitudinally through early infancy. We performed a logistic regression of the relationship between maternal abnormal temperature and six-week infant hospitalization, adjusting for gestational age and 10-minute APGAR score at birth.

RESULTS

Of the 648 postpartum participants from the parent study who agreed to enrol their neonates in the sub-study, 100 (15%) mothers had abnormal temperature. The mean maternal age was 24.6 (SD 5.3) years, and the mean parity was 2.3 (SD 1.5). There were more preterm babies born to mothers with abnormal maternal temperature (10%) compared to 1.1% to mothers with normal temperature (p=˂0.001). While the majority of newborns (92%) had a 10-minute APGAR score > 7, 14% of newborns whose mothers had abnormal temperatures had APGAR score ˂7 compared to 7% of those born to mothers with normal postpartum temperatures (P = 0.02). Six-week outcome data was available for 545 women and their infants. In the logistic regression model adjusted for gestational age at birth and 10-minute APGAR score, maternal abnormal temperature was not significantly associated with the composite adverse infant health outcome (being unwell or dead) between birth and six weeks' age (aOR = 0.35, 95% CI 0.07-1.79, P = 0.21). The 10-minute APGAR score was significantly associated with adverse six-week outcome (P < 0.01).

CONCLUSIONS

While our results do not demonstrate an association between abnormal maternal temperature and newborn and early infant outcomes, good routine neonate care should be emphasized, and the infants should be observed for any abnormal findings that may warrant further assessment.

TARGET JOURNAL

BMC Pregnancy and Childbirth ( https://bmcpregnancychildbirth.biomedcentral.com/ ).

Fever in childbirth: a mini-review of epidural-related maternal fever

Fever during childbirth, which is often observed in clinical settings, is characterized by a temperature of 38°C or higher, and can occur due to infectious and non-infectious causes. A significant proportion of non-infectious causes are associated with epidural-related maternal fever during vaginal delivery. Therapeutic interventions are required because fever has adverse effects on both mother and newborn. Effective treatment options for ERMF are lacking. As it is difficult to distinguish it from intrauterine infections such as chorioamnionitis, antibiotic administration remains the only viable option. We mentioned the importance of interleukin-1 receptor antagonist in the sterile inflammatory fever pathway and the hormonal influence on temperature regulation during childbirth, an important factor in elucidating the pathophysiology of ERMF. This review spotlighted the etiology and management of ERMF, underscoring recent advancements in our understanding of hypothalamic involvement in thermoregulation and its link to sterile inflammation. We propose to deepen the understanding of ERMF within the broader context of autonomic neuroscience, aiming to foster the development of targeted therapies.

Clinical chorioamnionitis at term: definition, pathogenesis, microbiology, diagnosis, and treatment

Clinical chorioamnionitis, the most common infection-related diagnosis in labor and delivery units, is an antecedent of puerperal infection and neonatal sepsis. The condition is suspected when intrapartum fever is associated with two other maternal and fetal signs of local or systemic inflammation (eg, maternal tachycardia, uterine tenderness, maternal leukocytosis, malodorous vaginal discharge or amniotic fluid, and fetal tachycardia). Clinical chorioamnionitis is a syndrome caused by intraamniotic infection, sterile intraamniotic inflammation (inflammation without bacteria), or systemic maternal inflammation induced by epidural analgesia. In cases of uncertainty, a definitive diagnosis can be made by analyzing amniotic fluid with methods to detect bacteria (Gram stain, culture, or microbial nucleic acid) and inflammation (white blood cell count, glucose concentration, interleukin-6, interleukin-8, matrix metalloproteinase-8). The most common microorganisms are Ureaplasma species, and polymicrobial infections occur in 70% of cases. The fetal attack rate is low, and the rate of positive neonatal blood cultures ranges between 0.2% and 4%. Intrapartum antibiotic administration is the standard treatment to reduce neonatal sepsis. Treatment with ampicillin and gentamicin have been recommended by professional societies, although other antibiotic regimens, eg, cephalosporins, have been used. Given the importance of Ureaplasma species as a cause of intraamniotic infection, consideration needs to be given to the administration of antimicrobial agents effective against these microorganisms such as azithromycin or clarithromycin. We have used the combination of ceftriaxone, clarithromycin, and metronidazole, which has been shown to eradicate intraamniotic infection with microbiologic studies. Routine testing of neonates born to affected mothers for genital mycoplasmas could improve the detection of neonatal sepsis. Clinical chorioamnionitis is associated with decreased uterine activity, failure to progress in labor, and postpartum hemorrhage; however, clinical chorioamnionitis by itself is not an indication for cesarean delivery. Oxytocin is often administered for labor augmentation, and it is prudent to have uterotonic agents at hand to manage postpartum hemorrhage. Infants born to mothers with clinical chorioamnionitis near term are at risk for early-onset neonatal sepsis and for long-term disability such as cerebral palsy. A frontier is the noninvasive assessment of amniotic fluid to diagnose intraamniotic inflammation with a transcervical amniotic fluid collector and a rapid bedside test for IL-8 for patients with ruptured membranes. This approach promises to improve diagnostic accuracy and to provide a basis for antimicrobial administration.

Training in neonatal neurocritical care: A case-based interdisciplinary approach

Interdisciplinary fetal-neonatal neurology (FNN) training strengthens neonatal neurocritical care (NNCC) clinical decisions. Neonatal neurological phenotypes require immediate followed by sustained neuroprotective care path choices through discharge. Serial assessments during neonatal intensive care unit (NICU) rounds are supplemented by family conferences and didactic interactions. These encounters collectively contribute to optimal interventions yielding more accurate outcome predictions. Maternal-placental-fetal (MPF) triad disease pathways influence postnatal medical complications which potentially reduce effective interventions and negatively impact outcome. The science of uncertainty regarding each neonate's clinical status must consider timing and etiologies that are responsible for fetal and neonatal brain disorders. Shared clinical decisions among all stakeholders' balance "fast" (heuristic) and "slow" (analytic) thinking as more information is assessed regarding etiopathogenetic effects that impair the developmental neuroplasticity process. Two case vignettes stress the importance of FNN perspectives during NNCC that integrates this dual cognitive approach. Clinical care paths evaluations are discussed for an encephalopathic extremely preterm and full-term newborn. Recognition of cognitive errors followed by debiasing strategies can improve clinical decisions during NICU care. Re-evaluations with serial assessments of examination, imaging, placental-cord, and metabolic-genetic information improve clinical decisions that maintain accuracy for interventions and outcome predictions. Discharge planning includes shared decisions among all stakeholders when coordinating primary care, pediatric subspecialty, and early intervention participation. Prioritizing social determinants of healthcare during FNN training strengthens equitable career long NNCC clinical practice, education, and research goals. These perspectives contribute to a life course brain health capital strategy that will benefit all persons across each and successive lifespans.

A biased coin up-and-down sequential allocation trial to determine the ED90 of intrathecal sufentanil combined with ropivacaine 2.5 mg for labor analgesia

Purpose

To determine the 90 percent effective dose (ED90) of intrathecal sufentanil combined with ropivacaine 2.5 mg for labor analgesia and observe its safety for parturients and neonates.

Methods

We conducted a prospective, double-blind, biased coin up-and-down study. We injected a fixed 2.5 mg ropivacaine combined with a designated dose of sufentanil intrathecally to observe the labor analgesic effect. The initial dose of sufentanil was assigned 1.0 μg, and the remaining doses were assigned as per the biased coin up-and-down method. The criterion of successful response was defined as VAS ≤ 30 mm after intrathecal injection at 10 min. Safety was evaluated in terms of maternal and neonatal outcomes.

Results

The ED90 dose of intrathecal sufentanil combined with ropivacaine 2.5 mg (0.1%, 2.5 mL) was 2.61 μg (95% CI, 2.44 to 2.70 μg) by isotonic regression. No respiratory depression, hypotension, or motor block was observed. Thirty-one (77.5%) parturients complained of pruritus, and 14 (35.0%) suffered nausea and vomiting. Three neonates reported a 1 min Apgar score of ≤7, and none reported a 5 min Apgar score of ≤7.

Conclusion

The ED90 of intrathecal sufentanil combined with ropivacaine 2.5 mg for labor analgesia was 2.61 μg. The dose is safe for parturients and neonates.

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.

Causes and consequences of fever in Amazonian pregnant women: A large retrospective study from French Guiana

OBJECTIVE

The aim of this study was to describe different causes and consequences of fever during pregnancy in Western French Guiana and along the Maroni River.

STUDY DESIGN

A retrospective single-center study including all patients with a history of documented fever ≥ 38°C during pregnancy at the West French Guiana Hospital for 9 years. Postpartum fever and nosocomial infections were excluded. We focused on medical history and on clinical and biological findings. Causes were characterized as confirmed or uncertain and then classified as preventable or non-preventable.

RESULTS

A total of 940 pregnant women who experienced at least one episode of fever were included and compared to 23,811 deliveries who occurred during the same period without documented fever. Among them, 43.7% (411/940) were in labor. About 3.7% (35/940) of febrile pregnant women had at least two episodes of fever, while 0.3% (3/940) had a coinfection at the time of diagnosis, resulting in a total of 978 febrile episodes. Among them, causes remained unknown or uncertain in 7.6% (75/978) and 0.9% (9/978) of cases, respectively. Among confirmed causes of fever throughout pregnancy (n = 483), the most common known cause was arbovirus infection (146/483, 30.2%), followed by urinary tract infection (134/483, 27.7%), chickenpox (27/483, 5.6%), and gastrointestinal (14/483, 2.9%) and pulmonary infections (10/483, 2%). Mothers with fever had a higher risk of cesarean section (19.8% vs 15.5%, aOR 1.3 [95% CI 1.14-1.6], stillbirth (5.5% versus 1.9%, aOR 2.7 [95% CI 2-3.7]), and preterm delivery < 34 weeks of gestation (7.2% vs 4.7%, aOR 1.5 [95% CI 1.2-2].

CONCLUSIONS

In the Amazon region, causes of fever are diverse and often associated with epidemic waves, notably arboviruses. This must be considered when exploring possible causes of fever during pregnancy in these localities, including fetal anomalies and/or fetal loss. Physicians should consider the epidemiological context and avoid generalizations. Given the impact of emergent agents such as arboviruses on pregnancy, particular attention must be paid to the epidemiological context. This study can also help clinicians when managing fever in pregnant travelers or in their partner after having visited exposed areas. In this context, fetal abnormalities and adverse obstetric outcomes should be explored accordingly.

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.

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.