|Year : 2020 | Volume
| Issue : 2 | Page : 106-110
Does labor epidural cause a rise in maternal temperature? An observational study at a tertiary care hospital of a developing country
Samina Ismail, Asiyah Aman, Kashif Munshi
Department of Anaesthesiology, Aga Khan University Hospital, Karachi, Pakistan
|Date of Submission||30-Mar-2020|
|Date of Acceptance||22-Apr-2020|
|Date of Web Publication||20-Aug-2020|
Dr. Samina Ismail
Department of Anaesthesiology, Aga Khan University Hospital, Stadium Road P.O. Box 3500, Karachi 74800
Source of Support: None, Conflict of Interest: None
Background and Objective: There has been a concern regarding maternal hyperthermia with labor epidural in developed countries. This study aimed to determine the frequency of rise in maternal temperature after labor epidural placement in a tertiary care hospital of a developing country. Materials and Methods: After approval from the institutional ethics review committee and informed consent, this observational cohort study was conducted on 494 nulliparous women fulfilling the inclusion criteria and requesting labor epidural. Maternal temperature was recorded by a standardized method soon before institution of labor epidural (baseline temperature) and then hourly after its placement for up to 6 h maximum or till delivery. Neonatal outcome was observed by recording Apgar score at 1 and 5 min and intensive care admissions. Results: There was a steady rise of mean temperature from baseline (36.26 ± 0.31), each hour after institution of labor epidural. The percentage of patients showing a rise in temperature increased each hour from 45% in first hour to more than 56% in the sixth hour. The temperature of ≥37.5°C was considered as hyperthermia and was observed in four patients (0.81%). The median temperature difference was not statistically significant within time point (P > 0.05). Apgar scores of newborns born to mothers with hyperthermia were 8 at 1 min and 9 at 5 min with no intensive care admissions. Conclusion: Frequency of maternal hyperthermia was found to be low compared to the incidence reported from developed countries, most probably due to difference in obstetric practice and patients demographics.
Keywords: Developing country, hyperthermia, labor epidural, maternal temperature
|How to cite this article:|
Ismail S, Aman A, Munshi K. Does labor epidural cause a rise in maternal temperature? An observational study at a tertiary care hospital of a developing country. J Obstet Anaesth Crit Care 2020;10:106-10
|How to cite this URL:|
Ismail S, Aman A, Munshi K. Does labor epidural cause a rise in maternal temperature? An observational study at a tertiary care hospital of a developing country. J Obstet Anaesth Crit Care [serial online] 2020 [cited 2021 Mar 9];10:106-10. Available from: https://www.joacc.com/text.asp?2020/10/2/106/292734
| Introduction|| |
Epidural analgesia is considered a gold standard for effective pain relief during labor. However, there has been a concern regarding a rise in maternal temperature since 1989, when it was first described by Fusi et al. Since then there has been a debate on this issue with number of observational studies,,, and randomized control trail,, supporting this association. However, criticisms on studies showing the association of maternal hyperthermia and labor epidural analgesia include selection bias, differences due to variable obstetric practices, protocol violation, and crossover and the fact that systemic mu-opioid agonist given to control group has an antipyretic effect.
Multiple theories have been proposed to account for the rise in maternal temperature during labor epidural; however, the hypothesis of maternal inflammation mediated through increased levels of pro-inflammatory cytokines appears to be the most valid one. Investigators have reported significantly higher levels of maternal and fetal interleukin (IL) 6 in patients who develop an intrapartum fever after labor epidural analgesia.,
Maternal and fetal exposure to hyperthermia and inflammation is associated with adverse consequences. Women who develop intrapartum fever are more likely to receive antibiotics and neonates born to febrile mothers undergo increased rates of neonatal sepsis evaluation., Fetal exposure to hyperthermia, inflammation, or both, is associated with several adverse neurologic outcomes.
Most of the studies are done in the developed world; the reason could be the high rate of labor epidural as vital statistic data suggest that approximately 68% of nulliparous patients in the USA receive labor epidural analgesia for vaginal birth, and are therefore at risk of developing fever No studies are available from developing countries to show an association of labor epidural with maternal hyperthermia. It has been observed that differences in obstetric management of labor in conjunction with underlying demographic risk factors may account for the wide variation in observed rates of intrapartum fever following labor epidural analgesia. The difference in obstetric practices among developed and developing countries can yield different results. Therefore, the rationale of this study is to see if the rise in maternal temperature is as prevalent as in developed countries.
Therefore, the primary objective of this study was to determine the frequency of rise in temperature in parturient receiving labor epidural analgesia at a tertiary care hospital of a developing country. The secondary objective was to observe the outcomes of neonates born to mothers with hyperthermia; in terms of appearance, pulse, grimace, activity, and respiration (Apgar) score at 1 and 5 min and intensive care admissions.
| Materials and Methods|| |
This observational cohort study was conducted for 1 year from July 1, 2017 to June 30, 2018 in the labor room suite of a tertiary care hospital with the approximate annual birth rate ranging from 3500 to 5000. The sampling technique used was nonpurposive consecutive sampling.
After approval from institutional ethics review committee, all the parturient coming to the labor room suite requesting labor epidural and fulfilling our inclusion criteria were enrolled in the study after written informed consent. The inclusion criteria included nulliparous women with singleton pregnancies of >36 weeks gestation with vertex presentation. The exclusion criteria included women having a baseline temperature of >37.5°C prior to epidural insertion, ongoing infection, chorioamnionitis, and refusal to participate in the study.
A baseline oral temperature reading was recorded during the time when patient was not having labor pains and before the insertion of an epidural catheter. After epidural insertion, hourly oral temperature was recorded by the labor room nurse on an hourly basis till delivery or to a maximum of 6 h. The method of taking temperature was standardized and the nurses were trained to take the temperature during the contraction free interval when patient was not hyperventilating or having labor pains till delivery or to a maximum of 6 h. The temperature of >37.5°C was considered as hyperthermia. The ambient conditions were kept standardized according to the institutional policy. For neonatal outcome, Apgar score was observed at 1 and 5 min and the frequency of neonatal intensive care unit (NICU) admissions were also noted.
Data were collected by a designated research assistant, who was trained by the primary investigator to fill the data collection sheet, from the anesthesia labor epidural record form and nursing notes. A predesigned data collection sheet was used which included patients' demographics, cervical dilatation, comorbidities, mode of delivery, Apgar scores of newborns at 1 and 5 min, and NICU admission.
The temperature of a parturient with respect to time was noted until the delivery of the baby or to a maximum of 6 h.
All statistical analysis was performed using Statistical Packages for the Social Sciences, version 19.0 (SPSS, Chicago, Illinois). Frequency and percentage of rise in maternal temperature and neonatal categorical outcomes were reported. Mean and the standard deviation were estimated for continuous variables, and repeated measure analysis of variance (ANOVA) was used to observe the within difference. A value of P ≤ 0.05 was considered as significant.
| Results|| |
The study was conducted for 1 year from July 1, 2017 to June 30, 2018. There were 494 patients fulfilling the inclusion criteria and after written informed consent enrolled in the study. The maternal demographic characteristics in addition to gestational age in weeks, cervical dilatation at the time of epidural insertion, maternal comorbidity, and mode of delivery, Apgar scores at 1 and 5 min and neonatal admission are shown in [Table 1].
|Table 1: Maternal characteristic, mode of delivery, and neonatal outcome|
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The mean temperature at baseline was found to be 36.26 ± 0.31. Number (percentage) of parturient showing a rise in temperature from baseline each hour after labor epidural placement is shown in [Table 2]. There was a steady rise of temperature each hour after the institution of labor epidural from 0.1 to ≥1°C in 45% of patients in the first hour to more than 56% of patients in the fifth and sixth hours after labor epidural. Median maternal temperature with respect to time is shown in [Figure 1]. The median temperature difference was not statistically significant within time point (P > 0.05). Hyperthermia (temp >37.5°C) was observed in four patients (0.81%). Of four cases who had hyperthermia, one patient continued to have a temperature greater than 37.5°C from first to third hour, whereas other three patients had hyperthermia at fourth, fifth, and sixth hours. Characteristics of patients with hyperthermia (n = 4) are shown in [Table 3]. Three patients of these four were observed till the sixth hour. Apgar scores of newborns were 8 at 1 min and 9 at 5 min in all these patients with no NICU admissions.
|Table 2: Number (percentage) of parturient showing rise in temperature (degree centigrade) from baseline each hour|
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|Table 3: Characteristics of patients with hyperthermia (n=4, 0.81%) cases)|
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| Discussion|| |
The results of this prospective observational study illustrate that 45%–60% of women experienced a modest elevation of temperature (from 0.1% to ≤1°C) over 6 h of study period after the commencement of labor epidural. This is in concordance with the previous prospective observation trials in which women self-select their analgesia., Results of Fusi et al. showed an average increase by 1°C of vaginal temperature in the epidural group. Similarly, Camann et al. showed increase of tympanic temperature of 0.07 per hour on average in the patient having labor epidural, which confirmed that rise of temperature as observed by Fusi et al., was not an artifact of measuring temperature vaginally.
However, the results of this study showed that only 0.8% of women with labor epidural had clinical fever, defined as temperature ≥37.5°C. This incidence is very low compared to the reported incidence of 20% of women experiencing hyperthermia with labor epidural., The reason could be difference in obstetrics management of cases in conjunction with underlying demographic factors, which may be the reason for wide differences in observed rates of intrapartum fever. In the institution, where there this study is conducted, oxytocin is very commonly used to manage the first stage of labor and this can be a reason for shorter duration of labor and decreased frequency of intrapartum fever. Frolich et al. in their retrospective cohort study noticed a trend towards a net decrease in maternal temperature in the high dose oxytocin group as compared to the control group.
A protective effect of oxytocin is further supported by data from the consortium on safe labor. This large database study suggested that more aggressive labor management with higher dose oxytocin regimens was associated with shorter labors and a decreased risk of intrapartum fever.
The studies show an association between labor epidural and hyperthermia in women who self-select their analgesia., There is the chance of selection bias when interpreting data from studies as it is possible that the reason why these women choose epidural analgesia may be the reason that they are experiencing fever., Parturient having clinical or subclinical chorioamnionitis or, perhaps more generally an elevated inflammatory state may experience more pain and request epidural.
In addition, randomized control trials showing an association of hyperthermia and labor epidural are criticized because health care providers cannot be completely blinded to whether a parturient is undergoing labor with or without the epidural. Therefore, obstetric management in a patient comfortable with labor epidural can lead to frequent cervical examination or the allowance of women with an epidural to delay pushing after complete cervical dilatation. The two randomized controlled trials (RCTs) performed by Sharma et al., report a longer interval from initiation of epidural analgesia to the discovery of complete cervical dilatation (260.3 ± 188 vs. 199 ± 171 min, a value of P < 0.001; 302 = 189 vs. 261 = 188 min, P = 0.03). Duration of epidural analgesia has an effect on the development of fever, as seen in RCTs that randomize women to epidural analgesia initiated in early vs. late labor. This is also observed in this study that there was a rise in temperature with each hour after labor epidural placement.
In addition, few RCTs may suffer from bias, when systemic mu-opioid agonists analgesia groups are compared with an epidural group. Antipyretic effects of systemic opioids can be the reason for the decreased incidence of fever in this group of parturient.
Limitation of this study is not having a control group; however, the main objective of this study was to find the incidence of the rise of temperature in patients receiving labor epidural and not to compare women who did not receive the epidural. In addition according to the methodology of this study, patients were followed till delivery or maximum of 6 h of the study period except for those developing hyperthermia during this period. Therefore, it is possible that some patients who developed hyperthermia beyond 6 h of study period might have been missed.
The strength of this study is being first such a study performed in developing countries. The results of the study did confirm the steady rise of maternal temperature with labor epidural; however, the incidence of hyperthermia was low as compared to previous studies performed in developed countries. The reason for this difference can be due to differences in underlying demographic factors and obstetrics management. This finding can be an avenue for new research to study factors like demographics and obstetric management that leads to a decrease incidence of hyperthermia in patients having labor epidural.
| Conclusion|| |
Labor epidural does cause a steady rise of maternal temperature; however, frequency of developing hyperthermia in parturient receiving labor epidural analgesia was found to be low. This low incidence could be due to difference in obstetric practice compared to the developed countries with more expedited approach to delivery with increased use of oxytocin in the institution where the study was conducted.
We would like to thank Mr. Syed Amir Raza and Ms. Seharish Sher Ali from Department of Anesthesia, Aga Khan University, for their significant contributions in statistical analysis of results and formatting of the manuscript.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]