Maternal Temperature Monitoring During Labor: Concordance and Variability Among Monitoring Sites

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.

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.

Clinical management of deviations in maternal temperature during labour and childbirth: an evidence-based intrapartum care algorithm

AIM

The development of an evidence-based algorithm for the clinical management of deviations in maternal temperature during labour and childbirth.

POPULATION

Pregnant women at any stage of labour, with singleton, term (37-42 weeks) pregnancies at low risk of developing complications.

SETTING

Health facilities in low- and middle-income countries.

SEARCH STRATEGY

We searched for international guidelines and prioritised WHO guidelines. In addition, we searched for other sources of evidence in the Cochrane Database of Systematic Reviews, EMBASE, MEDLINE and CINAHL until June 2020. Studies were prioritised according to the hierarchy of evidence.

CASE SCENARIOS

Two case scenarios were identified: maternal hyperthermia and hypothermia. We developed a single algorithm including both, due to commonalities in diagnosis, monitoring and management of underlying causes. The underlying conditions covered in the pathway include maternal sepsis and infection, chorioamnionitis, pyelonephritis, lower urinary tract and respiratory infections. Key decision points in the algorithm are suspicion of condition, definition, differential diagnosis, monitoring and management.

CONCLUSIONS

We present an evidence-based algorithm to assist healthcare professionals in making decisions about appropriate clinical management of deviations in maternal temperature. Research is needed to assess the views of healthcare professionals and women accessing healthcare on the feasibility of implementing the algorithm.

TWEETABLE ABSTRACT

An evidence-based intrapartum care algorithm to support management of deviations in maternal temperature in labour and childbirth. #sepsis #maternitycare.

Fetal and maternal inflammatory response in the setting of maternal intrapartum fever with and without clinical and histologic chorioamnionitis

BACKGROUND

Both infectious and noninfectious causes of maternal fever have been linked to adverse neonatal outcomes including low Apg0ar scores, respiratory distress, hypotonia, and neonatal seizures. Even in the absence of infection, the occurrence of intrapartum fever is a strong risk factor for poor long-term neonatal developmental outcomes, including encephalopathy, cerebral palsy, and neonatal death.

OBJECTIVE

The primary objective of this study was to compare intrapartum and postpartum maternal and fetal umbilical cord serum levels of cytokines RANTES, interferon-ɣ, interleukin-1β, interleukin-2, interleukin-4, interleukin-6, interleukin-8, interleukin-10, interleukin-13, and tumor necrosis factor-α among nonfebrile patients, febrile patients without clinical chorioamnionitis, and febrile patient with clinical chorioamnionitis.

STUDY DESIGN

This study was conducted at the Richmond University Medical Center from May 15, 2020 to July 16, 2019. During this time, we recruited 30 nonfebrile patients at >36 gestational weeks who were in labor and collected umbilical cord and pre- and postdelivery maternal serum samples to evaluate the cytokine levels. Placentas were collected for pathologic review and to evaluate the histopathologic findings. These results were compared with 121 patients who developed a fever of >38°C during labor. The febrile patients were further divided based on the presence or absence of clinical chorioamnionitis. A secondary analysis was performed based on the presence of absence of histologic chorioamnionitis. Statistical analysis was performed using IBM Statistical Package for the Social Sciences version 25.0. For the 3 group comparisons, a P value of <.017 was considered statistically significant after application of a Bonferroni correction.

RESULTS

A total of 151 patients were included in the study; 30 were nonfebrile patients, 46 were febrile patients with a diagnosis of clinical chorioamnionitis, and 75 were febrile patients without clinical chorioamnionitis. Compared with nonfebrile patients, umbilical cord serum interferon-ɣ, interleukin-1β, interleukin-6, interleukin-8, RANTES, and tumor necrosis factor-α levels were elevated in the presence of maternal hyperthermia irrespective of the diagnosis of clinical chorioamnionitis. Interleukin-6 umbilical cord levels were more than doubled from 63.60 pg/mL (6.09-1769.03 pg/mL) in febrile patients with no clinical chorioamnionitis to 135.77 pg/mL (1.86-6004.78 pg/mL) in febrile patients with clinical chorioamnionitis, making it the only cytokine that was significantly different between these 2 groups. When comparing the intrapartum maternal serum, we found a significant elevation in the interleukin-10, RANTES, and tumor necrosis factor-α levels in the febrile group irrespective of the presence of clinical chorioamnionitis when compared with the nonfebrile group. In the postpartum maternal blood evaluations, tumor necrosis factor-α was the only cytokine that was significantly higher in febrile patients than in nonfebrile controls.

CONCLUSION

In the setting of intrapartum fever, maternal cytokine profiles were similar irrespective of the diagnosis of clinical chorioamnionitis. Even in the absence of clinical or histologic chorioamnionitis, maternal hyperthermia induced elevations in fetal cytokines.

Intrauterine inflammation, infection, or both (Triple I): A new concept for chorioamnionitis

Chorioamnionitis is a common cause of preterm birth and may cause adverse neonatal outcomes, including neurodevelopmental sequelae. Chorioamnionitis has been marked to a heterogeneous setting of conditions characterized by infection or inflammation or both, followed by a great variety in clinical practice for mothers and their newborns. Recently, a descriptive term: "intrauterine inflammation or infection or both" abbreviated as "Triple I" has been proposed by a National Institute of Child Health and Human Development expert panel to replace the term chorioamnionitis. It is particularly important to recognize that an isolated maternal fever does not automatically equate to chorioamnionitis. This article will review the current literature on chorioamnionitis, and introduce the concept of Triple I, as well as recommendations for assessment and management of pregnant women and their newborns with a diagnosis of Triple I.

Fetal and maternal temperatures during labor and delivery: a prospective descriptive study

OBJECTIVE

The objective of this study is to study the fetal scalp temperature (FST) and maternal axillary temperature (MAT) during vaginal delivery relative to progression of labor, uterine contractions (UC) and epidural analgesia (EDA), and to construct normal temperature reference ranges related to stage of labor.

MATERIAL AND METHODS

Temperatures were recorded continuously in labor of 132 women with a bi-metal temperature sensor attached to the axilla (MAT) and a similar sensor mounted in a scalp electrode (FST). The temperature data were stored electronically and analyzed offline at cervical dilatations of 2-3, 5, 7-8, and 10 cm, and at full retraction. The FST was read before, at increasing, at peak, at decreasing, and after UC. The MAT and FST curves were compared with mixed-effect models statistics for repeated measurements. A two-tailed p <.05 was considered significant.

RESULTS

The FST did not vary during UC (p = .24). Both FST and MAT increased linearly by progression of labor (both p < .001). The increases in temperatures were greater with EDA than without (p < .001).

CONCLUSIONS

During UC, the FST showed no alteration. Both FST and MAT increased significantly by progression of labor, and significantly more in the presence of EDA. The presented normal temperature reference ranges can be used for future research.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Evaluation and Management of Women and Newborns With a Maternal Diagnosis of Chorioamnionitis: Summary of a Workshop

In January 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development invited an expert panel to a workshop to address numerous knowledge gaps and to provide evidence-based guidelines for the diagnosis and management of pregnant women with what had been commonly called chorioamnionitis and the neonates born to these women. The panel noted that the term chorioamnionitis has been used to label a heterogeneous array of conditions characterized by infection and inflammation or both with a consequent great variation in clinical practice for mothers and their newborns. Therefore, the panel proposed to replace the term chorioamnionitis with a more general, descriptive term: "intrauterine inflammation or infection or both," abbreviated as "Triple I." The panel proposed a classification for Triple I and recommended approaches to evaluation and management of pregnant women and their newborns with a diagnosis of Triple I. It is particularly important to recognize that an isolated maternal fever is not synonymous with chorioamnionitis. A research agenda was proposed to further refine the definition and management of this complex group of conditions. This article provides a summary of the workshop presentations and discussions.

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.

The association of maternal intrapartum subfebrile temperature and adverse obstetric and neonatal outcomes

BACKGROUND

Subfebrile intrapartum maternal temperature is very common, yet there is sparse evidence regarding its causes or its effects on perinatal outcomes. We examined whether mild temperature elevation during labour is a risk marker for adverse obstetric and neonatal outcomes.

METHODS

A retrospective cohort analysis including 42 601 term, singleton live-births in two medical centres between 2003 and 2010 was performed. This study compared women who experienced a maximal intrapartum temperature of ≤37°C with women who experienced subfebrile intrapartum temperature (37.1-37.9°C). Adjusted risks for adverse obstetric and neonatal outcomes were calculated by using multivariable logistic regression models.

RESULTS

Compared with maternal temperature ≤ 37°C, subfebrile temperature was associated with higher rates of primary caesarean deliveries {adjusted odds ratios [aOR] = 1.36 [95% confidence interval (CI) 1.25, 1.49])} and assisted vaginal deliveries (aOR = 1.20 [95% CI 1.11, 1.30]), as well as with greater risks of early neonatal sepsis (aOR = 2.66 [95% CI 1.88, 3.77]), neonatal intensive care unit admissions (aOR = 1.40 [95% CI 1.08, 1.83]), and neonatal asphyxia or seizures (aOR = 3.18 [95% CI 1.51, 6.70]). Mildly elevated maternal intrapartum temperature (37.1-37.5°C) was also associated with adverse outcomes.

CONCLUSIONS

Maternal intrapartum subfebrile temperature may be an indicator of operative delivery and neonatal morbidity. Further research is needed to confirm these findings and to reveal underlying mechanisms.

Maternal and fetal oxidative stress and intrapartum term fever

OBJECTIVE

The association between maternal chorioamnionitis and fetal oxidative stress has not been well established.

STUDY DESIGN

A nested case control study was performed within a prospective cohort of term nulliparous women: 20 cases (intrapartum fever of >100.4 degrees F) and 20 afebrile controls. Oxidative stress was assessed using ThioGlo-1 (TG-1; Calbiochem, San Diego, CA) fluorescent sulfhydryl detection. Median levels (+/- interquartile range) of protein-thiol sulfhydryls were compared.

RESULTS

In early labor, maternal oxidative stress (lower protein sulfhydryls) was significantly higher in those women who subsequently had intrapartum fever develop (79.87 +/- 22.88 vs 127.73 +/- 43.79 counts/second per microg protein; P < .001). In contrast, cord serum sulfhydryls were not different between groups (75.77 +/- 14.00 vs 75.04 +/- 17.83 counts/second per microg protein; P = .99)

CONCLUSION

Our data suggest that the term human fetus is protected from maternal oxidative stress associated with intrapartum fever. However, maternal oxidative status in early labor is associated with subsequent intrapartum fever. Optimal fetal neuroprotection will require a more precise knowledge of pathogenic mechanisms.

MATERNAL TEMPERATURE IN LABOUR

In this review, we are concerned primarily with pyrexia (hyperthermia; increased maternal temperature in labour) as hypothermia is rare and usually iatrogenic (as in hypothermia for cardiac bypass surgery). We start by reviewing the factors determining maternal temperature, and how it can be measured. We move on to the effects of the commonest cause of maternal pyrexia in labour in modern obstetric practice in developed countries, epidural anaesthesia. We then discuss the most feared cause of maternal pyrexia in labour, chorioamnionitis.

Intrapartum temperature changes following the intravenous crystalloid bolus for epidural analgesia

OBJECTIVE

To assess the effect of the intravenous crystalloid bolus given before epidural analgesia on maternal temperature during labour. Multiple studies have demonstrated a hyperthermic trend in parturient women receiving epidural analgesia. This temperature rise may be affected by the pre-epidural intravenous crystalloid bolus.

METHODS

Intrapartum oral temperatures were recorded in 40 singleton parturient women immediately before and after an intravenous bolus of Ringer's lactate solution (1L at room temperature [21 degrees C]) and at one hour after standardized insertion of an epidural catheter for analgesia. Exclusion criteria included antibiotic administration, chorioamnionitis, and initial maternal temperature above 37.5 degrees C. Group means were compared using the 2-tailed paired Student t test.

RESULTS

There was no significant trend towards a decrease in maternal temperature after the crystalloid bolus (mean change -0.07 degree C, P = 0.33). Similarly, there was no initial trend towards an increased maternal temperature after epidural insertion (mean change + 0.02 degrees C, P > 0.7). Separate analyses using parity, body mass index, and bolus duration as covariates showed that these variables did not affect maternal temperature changes (P > or = 0.2).

CONCLUSION

Our study indicates that intravenous infusion of a crystalloid bolus at room temperature before induction of epidural analgesia does not significantly decrease parturient temperature.