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

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.

Establishing a risk score for prediction of intrapartum cesarean delivery among older women: A retrospective cohort study

OBJECTIVE

To determine risk factors and to develop a risk prediction score for intrapartum cesarean delivery (CD) in women over 40 years old.

STUDY DESIGN

A retrospective cohort study, in a single university-affiliated tertiary medical center. All women aged 40 years or more who planned a trial of labor between 2012 and 2022. Women who opted for an elective CD and those with non-viable fetuses were excluded. Maternal and neonatal characteristics of women who delivered vaginally were compared to those who underwent an intrapartum CD. Risk factors were examined using univariate and multivariate analysis. A score was developed to predict the need for intrapartum CD. We assessed a receiver operating characteristic curve to evaluate the performance of our model.

MAIN OUTCOME MEASURE

An unplanned intrapartum cesarean section.

RESULTS

During the study period, 122,583 women delivered at our center, of whom 6122 (4.9 %) aged 40 years or more attempted a trial of labor. Of them, 428 (7 %) underwent intrapartum CD. Several independent risk factors were identified, including nulliparity, regional anesthesia, induction of labor, use of antibiotics during labor, multiple gestation, previous cesarean delivery, and the presence of gestational diabetes or preeclampsia. A risk score model, employing a cut-off of 7, demonstrated successful prediction of intrapartum CD, with an area under the curve of 0.86.

CONCLUSION

The score model for intrapartum CD can be used by caregivers to offer a more informed consultation to women aged 40 years or more deciding on the mode of delivery.

Analysis of Maternal and Fetal Oxidative Stress During Delivery with Epidural Analgesia

Childbirth is a stressful event for mothers, and labor epidural analgesia (LEA) may reduce mental stress. Mental stressors include labor pain, fear, and anxiety, which induce oxidative stress. In this study, we focused on oxidative stress during delivery and conducted a cross-sectional analysis of maternal and fetal oxidative stress. The participants included 15 women who received LEA (LEA group) and 15 who did not (No LEA group). Participants with a gestational age of < 37 weeks, BMI of ≥ 35 kg/m2, cerebrovascular or cardiovascular complications, multiple pregnancies, gestational hypertension, gestational diabetes, chronic hypertension, thyroid disease, birth weight of < 2,500 g, emergency cesarean section, or cases in which epidural anesthesia was re-administered during delivery were excluded from the study. Maternal blood was collected on admission, and immediately after delivery, and umbilical artery blood was collected from the fetus. The oxidative stress status was assessed by measuring diacron-reactive oxygen metabolite (an index of the degree of lipid peroxide oxidation), biological antioxidant potential (an index of antioxidant capacity) and calculating the ratio of BAP/d-ROMs (an index of the oxidative stress). The results showed that maternal oxidative stress immediately after delivery was lower in the LEA group than in the No LEA group. Moreover, the fetuses experienced less oxidative stress in the LEA group than in the No LEA group. Taken together, these results suggest that LEA may reduce maternal and fetal oxidative stress associated with childbirth.

The relation between low-grade fever during prolonged rupture of membranes (>12 hours) at term and infectious outcomes: a retrospective cohort study

BACKGROUND

Intrapartum fever (>38°C) is associated with adverse maternal and neonatal outcomes. However, the correlation between low-grade fever (37.5°C-37.9°C) and adverse perinatal outcomes remains controversial.

OBJECTIVE

This study aimed to compare maternal and neonatal outcomes of women with prolonged rupture of membranes (≥12 hours) at term between those with low-grade fever and those with normal body temperature.

STUDY DESIGN

This retrospective study included women hospitalized in a tertiary university-affiliated hospital between July 2021 and May 2023 with singleton term and rupture of membranes ≥12 hours. Women were classified as having intrapartum low-grade fever (37.5°C-37.9°C) or normal body temperature (<37.5°C). The co-primary outcomes, postpartum endometritis and neonatal intensive care unit admission rates, were compared between these groups. The secondary maternal outcomes were intrapartum leukocytosis (>15,000/mm2), cesarean delivery rate, postpartum hemorrhage, postpartum fever, surgical site infection, and postpartum length of stay. The secondary neonatal outcomes were early-onset sepsis, 5-minute Apgar score of <7, umbilical artery cord pH<7.2 and pH<7.05, neonatal intensive care unit admission length of stay, and respiratory distress. The data were analyzed according to rupture of membranes 12 to 18 hours and rupture of membranes ≥18 hours. In women with rupture of membranes ≥18 hours, intrapartum ampicillin was administered, and chorioamniotic membrane swabs were obtained. The likelihood ratios and 95% confidence intervals were calculated for the co-primary outcomes. A multivariate logistic regression model was used to predict puerperal endometritis controlled for rupture of membranes duration, low-grade fever (compared with normal body temperature), positive group B streptococcus status, mechanical cervical ripening, cervical ripening by prostaglandins, artificial rupture of membranes, meconium staining, epidural analgesia, and cesarean delivery. A multivariate logistic regression model was used to predict neonatal intensive care unit admission controlled for rupture of membranes duration, low-grade fever, positive group B streptococcus status, mechanical cervical ripening, artificial rupture of membranes, meconium staining, cesarean delivery, and neonatal weight of <2500 g.

RESULTS

This study included 687 women with rupture of membranes 12 to 18 hours and 1109 with rupture of membranes ≥18 hours. In both latency groups, the rates were higher for cesarean delivery, endometritis, surgical site infections, umbilical cord pH<7.2, neonatal intensive care unit admission, and sepsis workup among those with low-grade fever than among those with normal body temperature. Among women with low-grade fever, the positive likelihood ratios were 12.7 (95% confidence interval, 9.6-16.8) for puerperal endometritis and 3.2 (95% confidence interval, 2.0-5.3) for neonatal intensive care unit admission. Among women with rupture of membranes ≥18 hours, the rates were higher of Enterobacteriaceae isolates in chorioamniotic membrane cultures for those with low-grade fever than for those with normal intrapartum temperature (22.0% vs 11.0%, respectively; P=.006). Low-grade fever (odds ratio, 9.0; 95% confidence interval, 3.7-21.9; P<.001), artificial rupture of membranes (odds ratio, 4.2; 95% confidence interval, 1.5-11.7; P=.007), and cesarean delivery (odds ratio, 5.4; 95% confidence interval, 2.2-13.4; P<.001) were independently associated with puerperal endometritis. Low-grade fever (odds ratio, 3.2; 95% confidence interval, 1.7-6.0; P<.001) and cesarean delivery (odds ratio, 1.9; 95% confidence interval, 1.1-13.1; P=.023) were independently associated with neonatal intensive care unit admission.

CONCLUSION

In women with rupture of membranes ≥12 hours at term, higher maternal and neonatal morbidities were reported among those with low-grade fever than among those with normal body temperature. Low-grade fever was associated with a higher risk of Enterobacteriaceae isolates in chorioamniotic membrane cultures. Moreover, low-grade fever may be the initial presentation of peripartum infection.

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.

In Situ Array Microextraction and Metabolic Profiling of Small Extracellular Vesicles to Guide and Monitor Maternal Delivery

The advantages of small extracellular vesicles (sEV) in disease management have become increasingly prominent, with the main challenge lying in meeting the demands of large-scale extraction and high-throughput analysis, a crucial aspect in the realm of precision medicine. To overcome this challenge, an engineered on-plate aptamer array (16×24 spots) is developed for continuous scale-up microextraction of plasma sEV and their in situ metabolic analysis using mass spectrometry. With this integrated array strategy, metabolic profiles of sEV are acquired from the plasma of 274 antenatal or postpartum women, reducing analysis time by half (7.5 h) and sample volume by 95% (only 0.125 µL usage) compared to the traditional suspension method. Moreover, using machine learning algorithms on sEV metabolic profiles, a risk score system is constructed that accurately assesses the need for epidural analgesia during childbirth and the likelihood of post-administration fever. The system, based on admission samples, achieves an impressive 94% accuracy. Furthermore, post-administration fever can be identified from delivery samples, reaching an overall accuracy rate of 88%. This work offers real-time monitoring of the childbirth process that can provide timely guidance for maternal delivery, underscoring the significance of sEV detection in large-scale clinical samples for medicine innovation and advancement.

Duration time of labor progression for pregnant women of vaginal birth after cesarean in Hubei, China

OBJECTIVE

There have been limited reports on the duration of labor progression in pregnant women undergoing vaginal birth after cesarean (VBAC). This study aimed to investigate the duration of labor progression during VBAC in Hubei, China.

METHODS

A total of 359 pregnant women undergoing VBAC were enrolled as the VBAC group, meeting the following criteria: singleton pregnancy, gestational age ≥ 37 weeks, live birth, history of cesarean delivery, and a willingness to attempt a vaginal delivery. At the same time, 359 primiparas successfully undergoing vaginal delivery were randomly enrolled in the control group at a 1:1 ratio. Subsequently, the durations of the first, second, and third stages of labor were comparatively analyzed between the two groups.

RESULTS

The duration of the first, second, and total stages of labor in the VBAC group was significantly shorter than that in the control group (p < 0.05). There was no significant difference in the duration of the third stage of labor between the two groups (p > 0.05). The amount of blood loss, the rate of postpartum hemorrhage (PPH), and episiotomy were higher in the VBAC group than in the control group (p < 0.05). The rate of labor analgesia and intrapartum fever in the VBAC group was significantly lower than that in the control group (p < 0.05).

CONCLUSION

The duration of labor progression of the first, second, and total stages of VBAC is shorter than that in primiparous women in our observation in China.

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.

Parturition at term: induction, second and third stages of labor, and optimal management of life-threatening complications-hemorrhage, infection, and uterine rupture

Childbirth is a defining moment in anyone's life, and it occurs 140 million times per year. Largely a physiologic process, parturition does come with risks; one mother dies every two minutes. These deaths occur mostly among healthy women, and many are considered preventable. For each death, 20 to 30 mothers experience complications that compromise their short- and long-term health. The risk of birth extends to the newborn, and, in 2020, 2.4 million neonates died, 25% in the first day of life. Hence, intrapartum care is an important priority for society. The American Journal of Obstetrics & Gynecology has devoted two special Supplements in 2023 and 2024 to the clinical aspects of labor at term. This article describes the content of the Supplements and highlights new developments in the induction of labor (a comparison of methods, definition of failed induction, new pharmacologic agents), management of the second stage, the value of intrapartum sonography, new concepts on soft tissue dystocia, optimal care during the third stage, and common complications that account for maternal death, such as infection, hemorrhage, and uterine rupture. All articles are available to subscribers and non-subscribers and have supporting video content to enhance dissemination and improve intrapartum care. Our hope is that no mother suffers because of lack of information.

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.

Association of maternal SARS-CoV-2 infection at the time of admission for delivery with labor process and outcomes of vaginal birth: A cohort study

INTRODUCTION

This study aimed to investigate the impact of maternal SARS-CoV-2 infection at the time of admission for delivery on labor process and outcomes of vaginal birth.

MATERIAL AND METHODS

A cohort study was carried out at the Obstetrics Department of Anhui Provincial Hospital, China, where universal reverse transcriptase polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 infection was introduced for all women admitted for labor and delivery from December 1-31, 2022. Women were divided into positive and negative groups based on the test result. All women having a singleton vaginal birth were included in final analysis. The effect of SARS-CoV-2 positivity on labor process and outcomes of vaginal birth was estimated by regression analyses.

RESULTS

Among a total of 360 women included, 87 had a positive SARS-CoV-2 test and 273 a negative test. Women in the positive group had an increased likelihood of having longer labor (median 9.3 vs 8.3 hours; sB [log-transformed] 0.19; 95% confidence interval [CI] 0.09-0.28), episiotomy (39.1% vs 23.8%; adjusted odds ratio [aOR] 2.31; 95% CI 1.27-4.21), grade III meconium-stained amniotic fluid (19.5% vs 7.0%; aOR 2.52; 95% CI 1.15-5.54) and postpartum hospital stay exceeding 37 hours (58.6% vs 46.5%; aOR 1.71; 95% CI 1.00-2.91). They had reduced rates exclusive breastfeeding (26.7% vs 39%; aOR 0.21; 95% CI 0.09-0.46) as well as mixed feeding (46.5% vs 52.2%; aOR 0.28; 95% CI 0.13-0.60) at 1 week postpartum. No significant differences were observed in other aspects of labor process and birth outcomes, including the uptake of labor analgesia, postpartum hemorrhage (>500 mL) or neonatal outcomes.

CONCLUSIONS

A positive maternal SARS-CoV-2 test in labor among women having vaginal birth was associated with a slightly longer duration of labor, increased likelihood of episiotomy, increased incidence of grade III meconium-stained amniotic fluid, a longer postpartum hospital stay and a lower rate of breastfeeding 1 week postpartum. However, it did not have an adverse impact on other birth outcomes.

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.