Epidural anesthesia during labor and delivery and postpartum hemorrhage

Maike Katja Sachs; Elisabeth Kapfhammer; Romana Brun; Lukas Kandler; Nicole Ochsenbein; Christian Haslinger

doi:10.1515/jpm-2024-0567

Article Open Access

Epidural anesthesia during labor and delivery and postpartum hemorrhage

Maike Katja Sachs , Elisabeth Kapfhammer , Romana Brun , Lukas Kandler , Nicole Ochsenbein and Christian Haslinger

Published/Copyright: May 23, 2025

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From the journal Journal of Perinatal Medicine Volume 53 Issue 7

Abstract

Objectives

Epidural analgesia is widely used for pain management during labor and delivery with inconsistent results regarding its influence on postpartum blood loss. Aim of our study was to investigate blood loss after vaginal delivery in women with epidural analgesia in consideration of established risk factors for postpartum hemorrhage (PPH) and by using a validated blood measurement technique.

Methods

This prospective study was performed at the University Hospital Zurich. Included were 699 women with vaginal deliveries after 34 weeks of pregnancy. Blood loss was assessed by a validated measurement technique. Risk factors for increased blood loss were assessed and stratified by epidural analgesia use. Significant variables were entered into a stepwise multivariate regression analysis.

Results

In the univariate analysis, women with epidural analgesia showed a significantly higher blood loss, compared to women without epidural analgesia. However, after multivariate regression analysis no association between increased blood loss and epidural anesthesia was observed. Furthermore, women with epidural analgesia were more often primiparous, experienced more often uterine atony and PPH, bleeding from perineal laceration, vacuum extraction, longer second stage of labor and bigger neonatal head circumference.

Conclusions

Epidural analgesia itself is not associated with increased postpartum blood loss. However, there is a higher incidence of PPH in deliveries with obstetric risk factors, in which more frequent use of epidural analgesia is observed. In other words, not epidural analgesia is the cause of PPH, but difficult obstetric settings are associated with both higher use of epidural analgesia and increased blood loss.

Keywords: postpartum bleeding; epidural; anesthesia during delivery

Introduction

The use of neuraxial techniques, such as epidural (EA) and combined spinal-epidural analgesia (CSEA), is the most effective modality for pain relief during labor [1], 2]. The use has increased worldwide over the past few decades [3]. In the United States as many as 70 % and in Europe about 50 % of women receive EA/CSEA during labor depending on availability and variation amongst geographic areas [1], 2]. In addition to providing analgesic benefits to the mother, benefits of neuraxial analgesia are improving maternal cardiovascular and pulmonary function during labor [4]. Furthermore EA/CSEA could be converted to surgical anesthesia if operative delivery is required [5]. However, there are unintended adverse effects of EA/CSEA and delivery outcomes with a possible higher rate of instrumental vaginal delivery, urinary retention and longer second stage of labor [6], 7]. Moreover, EA also has been discussed as a risk factor for postpartum hemorrhage (PPH), presumably by lengthening second stage of labor and negatively affecting the endogenous oxytocin level [8], [9], [10], [11], [12]. Additionally in the last few years, an increased number of cases of PPH has been noticed, both in low- and high-income countries [11]. Some authors presumed that the rising numbers of PPH might be observed due to an increased rate of interventions, especially EA/CSEA, the most prevalent intervention during delivery [11]. On the contrary, others assume that EA/CSEA seems to be a protective factor against severe blood loss in women with PPH [10]. The proposed mechanism is an immediate and effective management of PPH due to a present EA/CSEA [13].

In summary, the current body of evidence is inconsistent regarding the impact of increasing use of EA/CSEA on the incidence of PPH. The aim of our study was to evaluate the relationship between EA/CSEA and PPH.

Materials and methods

Study population

This is a secondary analysis of a prospective observational study on postpartum blood loss [14]. Study approval was given by the “Ethics Review Board of Zurich” prior to patient enrollment (KEK-ZH 2015-0011). Participants were enrolled from 10/2015 until 11/2016 at the University Hospital Zurich. Pregnant women gave full and informed consent before enrollment through obstetricians at the outpatient clinic of the University Hospital Zurich within the scope of regular pregnancy check-ups. Inclusion criteria were women underwent vaginal delivery. Exclusion criteria comprised a gestational age of less than 34+0 weeks, a maternal age below 18 years, multiple fetus pregnancies, breech presentation, bleeding disorders (i.e. blood-clotting disorders, primary coagulopathy etc.), cesarean section and peripartum diagnosis of placental pathology (placenta accreta spectrum) since the latter are not known to be caused by epidural analgesia but contribute to a significantly higher risk of postpartum hemorrhage as we have shown in a prior study on this cohort [14]. Demographic and clinical patient data entry was performed by the trained study staff.

Blood loss measurement technique

The blood loss measurement technique on our labor and delivery ward was validated by a hemoglobin based formula for blood loss in a previous study by Kahr et al. [15]. This real-time blood measurement comprises frequent visual, manual and weighed blood loss measurement with eventually application of a fluid collection bag with a quantitative scale attached to a drape in cases of PPH: directly after cord clamping, a fresh drape is placed below the woman’s pelvis. During the postpartum period, the weight of the drape is checked by lifting it and by weighting the drape on a neonatal scale, which is present in every delivery room. The application of the fluid collection bag with a scale was performed whenever the weighed blood loss accounted for more than 300 mL. At our institution, according to the WHO-definition, PPH is diagnosed in cases with blood loss is greater than or equal to 500 mL within 24 h after birth, while severe PPH is blood loss greater than or equal to 1,000 mL within 24 h.

Technique of epidural anaesthesia and of combined spinal/epidural anaesthesia performed at our institution

The institutional standard for perinatal neuraxial analgesia is CSEA. After obtaining written consent from the patient and checking the coagulation history and the corresponding laboratory parameters, CSEA is performed under sterile conditions. A spinal component, 0.5 mL Bupivacaine 0.25 % isobaric combined with 0.4 mL Sufentanil plus 1.1 mL NaCl is used. During the period of the study, a continuous infusion (7–9 mL/h) of Ropivacain 1 mg/mL combined with 0.25 μg/mL Sufentanil was used for epidural anesthesia started with a slight delay.

Regardless of the study results, the epidural component has since been further developed into a Programmed Intermittent Epidural Bolus (PIEB) mode with the same drug concentration and an hourly bolus of 6 mL.

Statistical analysis

Major patient characteristics (subdivided into maternal and perinatal characteristics) were displayed by using descriptive statistics (data given in percentage (number, n) or median±interquartile range, IQR). Chi-square test or Fisher`s exact test were applied for the comparison of nominal variables while quantitative variables were compared by Mann-Whitney U test after Kolmogorov-Smirnov and Shapiro-Wilk tests revealed not-normally distributed data. Data was stratified by the administration of epidural anesthesia. The influence of potential clinical risk factors on estimated blood loss involved Mann-Whitney-U or chi-square test (given as median (IQR) or r² and p-values). Stepwise multivariable linear regression analysis was performed to further analyze the identified risk factors for increased post-partum bleeding. Values are given as B (regression coefficient) (95 % Confidence Interval for B) and p-values. p<0.05 was accepted as statistically significant throughout the whole analysis. The statistical analyses for this study and data processing was conducted with SPSS (version 22, IBM, USA).

Results

Study population characteristics

The study population comprised 699 patients. Major patient characteristics are shown in Table 1 where stratification is based on the application of EA. 39 % (n=274) of our study population had an EA during labor. Age, gestational age (GA), body mass index (BMI), rates of placental abruption, preterm birth and neonatal weight were not different between groups. Women with EA were more likely to be primiparous, have a longer duration of second stage labor, require a vacuum delivery (no forceps delivery within the study population), experience increased bleeding from perineal laceration, have a neonate with a greater head circumference and exhibit higher rates of uterine atony, postpartum hemorrhage and exhibit a higher amount of blood loss (400 mL (300 mL; 500 mL) vs. 300 mL (250 mL; 400 mL), p<0.001).

Table 1:

Patient characteristics.

	Epidural analgesia n=274	No epidural analgesia n=425	p-Value
Maternal characteristics
Age, years	32 (28;35)	33 (28;36)	0.094
Gestational age, days	281 (273;285)	280 (273;285)	0.301
Parity	1 (1;2)	2 (1;2)	<0.001
Body mass index	23.4 (20.4;27.2)	23 (20.5;26.4)	0.502
Perinatal characteristics
Duration second stage of labor, min	116.5 (56.5; 175.0)	29.0 (12.4;62.2)	<0.001
Vacuum delivery	27.4 % (75)	9.6 % (41)	<0.001
Bleeding from perineal laceration	9.5 % (26)	3.8 % (16)	0.008
Placental abruption	0.4 % (1)	0.5 % (2)	0.835
Uterine atony	5.1 % (14)	3.5 % (15)	<0.001
Preterm birth (≥34 – <37 weeks GA)	1.5 % (4)	2.1 % (9)	0.813
Neonatal weight, g	3,380 (3,117;3,630)	3,350 (3,080;3,655)	0.827
Neonatal head circumference, cm	35.0 (34.0;36.0)	35.0 (34.0;36.0)	<0.001
Postpartum hemorrhage, PPH	25.9 % (71)	19.3 % (82)	0.020
Blood loss, ml	400 (300;500)	300 (250;400)	<0.001

Bold values represent to highlight statistically significant p-values.

EA was administered in 49.2 % of primiparous women (n=185) and 27.5 % of multiparous women (n=89, p<0.001). Generally, primiparous women underwent more often vacuum delivery (25.5 % of primiparous women (n=96) vs. 6.2 % of multiparous women (n=20, p<0.001)). Primiparous women with EA had the highest rate of vacuum delivery (37.3 % (n=69), also compared to primiparous women without EA (14.2 %, p<0.001)). Women without EA had lower vacuum deliveryrates (14.2 % of primiparous women and 6 % of multiparous women).

Vacuum delivery was also shown to be associated with increased bleeding from perineal lacerations (p=0.010) in our cohort.

Clinical risk factors for increased postpartum bleeding

Table 2 depicts clinical risk factors for increased postpartum bleeding. Neither maternal age, nor BMI, placental abruption or preterm birth showed associations with a significantly higher blood loss. Of the included risk factors, GA (p=0.002), parity (p<0.001), second stage labor duration (p<0.001), vacuum delivery (p<0.001), bleeding from perineal lacerations (p<0.001), uterine atony (p<0.001), neonatal weight (p<0.001) and head circumference (p<0.001) as well as epidural anaesthesia (p<0.001) were associated with increased bleeding in our univariate analysis.

Table 2:

Correlation of blood loss with maternal and perinatal characteristics.

Variables	Blood loss, mL
Variables	Median (IQR) or Pearson correlation coefficient r	p-Value
Maternal characteristics
Age	−0.019	0.612
Gestational age, days	0.118	0.002
Parity	−0.154	<0.001
Body mass index	−0.023	0.554
Perinatal characteristics
Duration second stage of labor, min	0.169	<0.001
Vacuum delivery		<0.001
Yes	400 (300;575)
No	300 (250;400)
Bleeding from perineal laceration		<0.001
Yes	550 (500;800)	<0.001
No	300 (250;400)
Placental abruption		0.089
Yes	500 (350)
No	300 (300;400)
Preterm birth (≥34 – <37 weeks GA)		0.184
Yes	300 (200;375)
No	300 (300;400)
Neonatal weight, g	0.137	<0.001
Neonatal head circumference, cm	0.161	<0.001
Epidural analgesia		<0.001
Yes	400 (300;500)
No	300 (250;400)

Bold values represent to highlight statistically significant p-values.

Stepwise multivariable linear regression analysis was conducted to test the associations between EA and measured blood loss. Ultimately, EA did not show statistical significance in multivariable analysis, as well as parity, neonatal weight and gestational age. Clinical risk factors for increased blood loss that remained associated with increased postpartum blood loss were uterine atony (strongest association with blood loss), bleeding from perineal lacerations, vacuum delivery, neonatal head circumference and duration of second stage labor (Table 3).

Table 3:

Clinical risk factors for increased blood loss.

	Regression coefficient B (95 % CI)	p-Value
Uterine atony	567.4 (509.7–625.2)	<0.001
Bleeding from perineal laceration	212 (162.8–261.8)	<0.001
Vacuum extraction	74.2 (39.9–108.5)	<0.001
Neonatal head circumference, cm	12.8 (3.9–21.7)	0.005
Duration second stage of labor, min	0.24 (0.04–0.4)	0.016

Bold values represent to highlight statistically significant p-values.

Discussion

Our study analyses the relationship of EA on postpartum blood loss while considering known risk factors forPPH. The findings suggest that there are independent drivers for increased postpartum blood loss, including uterine atony, bleeding from perineal lacerations, vacuum delivery, second stage labor duration and neonatal head circumference. According to our findings, EA is not causally associated with PPH on stepwise multivariable linear regression analysis. A prior study on PPH even reports a protective effect of EA on severe bleeding after adjusting for multiple risk factors in their cohort [16]. The protective effect is explained by a prompter PPH management such as examination of the vagina and cervix or manual removal of the placenta which usually require anaesthesia. Women with a placental pathology were excluded in our study, as this was not attributed to the prenatal administration of EA and at the same time poses an important independent cause for severe PPH.

Some studies have explored the relationship between EA and PPH [8], [16], [17], [18], [19]. However, these studies are limited by their retrospective design. Notably they did not separately consider various other risk factors such as retained placenta, prolonged second stage of labor, fetal macrosomia or polyhydramnion in a multivariable analysis, which are known to contribute to the development of postpartum hemorrhage. Consistent with our findings, others found no significant associations between EA and PPH in primiparous women [7], 9], 20].

Risk factors for increased blood loss following multivariable analysis in this study have been identified as such also in prior studies. The association of uterine atony with increased blood loss is evident, representing the most common cause of PPH [20]. Longer duration of second stage labor in association with EA has been reported by various studies as a risk factor for PPH [21], [22], [23], [24], [25]. Although our analysis reveals a statistically significant association, its independent clinical effect is rather low: A 1 min extension of second stage labor duration led to 0.24 mL increase in blood loss (i.e. 60 min longer duration of second stage labor would lead to about 14.4 mL more blood loss) (Table 3). The same applies for the neonatal head circumference, whereupon with every centimetre of circumference the total blood loss would rise by 12.8 mL. Further, the associations between perineal lacerations and higher blood loss is established [26], 27] and accounted for about 212 mL (162.8–261.8 mL) higher blood loss in our cohort (Table 3).

Rossen et al. have reported that vaginal operative deliveries had not been related to PPH while others found similar results to ours, revealing an association of vaginal operative deliveries with increased blood loss [24], 28].

To our best knowledge none of the studies mentioned above used a validated system for blood loss measurement. Postpartum blood loss was estimated mostly visually which has been proven to be inaccurate [29], [30], [31]. We have previously demonstrated that the blood loss measurement in our patient cohort correlates well with the calculated blood loss, based on hemoglobin differences before and after parturition, above all in vaginal deliveries [15]. Especially in cases of increased blood loss, the quantitative fluid collection bag was always applied, which poses a substantial strength of our study design.

The relationship between EA, duration of second stage labor, neonatal head circumference, vacuum extraction, and increased postpartum blood loss is difficult to unravel. An extensive study in the Netherlands of more than 600,000 deliveries did not report an increase of vaginal operative deliveries though the rate of EA rose from 7.7 to 21.0 % during the 10-year study interval [32]. However, several studies report an association of EA and requirement for vaginal operative deliveries [18], 24], 33]. In our cohort, significantly more primiparous than multiparous women received EA while the overall use of EA was low when being compared to a rate of 73.1 % within the United States [1]. Vaginal operative delivery was more common in primiparous women, no matter if they received EA or not.As indicated in previous studies, our data suggest that the use of epidural analgesia increases the chance for vaginal delivery and may contribute to a reduction in the caesarean section rate [18]. Basically, primiparas required both, EA and vacuum deliveries, more often. The study design does not allow to conclude an answer to the question whether primiparas had more vacuum delivery due to EA or if increased administration of EA was a consequence of a more complicated course of delivery with prolonged duration of labor in primiparas, e.g. due to bigger fetal head circumference. It was not possible to evaluate if the course of delivery would have led to a vaginal operative delivery in any case. This means the differentiation between cause and effect remains difficult in this setting. However, since EA was excluded as risk factor for increased bleeding after multivariable regression analysis, we conclude that increased postpartum blood loss in our cohort was rather caused by obstetric complications, which themselves were also associated with the need for epidural analgesia.

Strength and limitation

There are several strengths of this study to be mentioned. An evidence based PPH protocol was implemented and followed at our perinatal center, assuring a standardized treatment of PPH during the study period. In addition, a reliable real-time obstetric blood loss measurement technique was used on our center`s labor and delivery ward, distinguishing this study from previous studies. The prospective collection of clinical data, focusing on the documentation of risk factors for PPH, provides a complete clinical dataset, which is inevitable for any reliable multivariable analysis that itself is essential to answer the question if epidural analgesia is an independent risk factor for increased postpartum blood loss or rather complicated delivery led to both EA and increased blood loss.

A weakness of this study is attributed to the fact that the influence of EA on postpartum blood loss was assessed in a secondary analysis of another prospective study. However, only a prospective randomized controlled trial (EA vs. no EA) in women who wish to receive an EA might answer this question definitely. In any prospective non-interventional study, such as ours, it is difficult to assess if EA was administered due to a complicated delivery owed to a fetal malposition such as occiput posterior position which is associated with prolonged second stage labor and increased blood loss per se, or if prolonged second stage labor with its associated complications was a consequence of EA. Analgesics other than EA, such as laughing gas, nalbuphine and patient-controlled analgesia pump were not included in the analysis. Also, for testing correlation of our not-normally distributed data, we used Pearson instead of Spearman correlation with a multivariable linear regression analysis, which may compromise the robustness of statistics.

Conclusions

Based on our findings we conclude that EA itself does not have a significant impact on postpartum blood loss. Factors that had a significant influence on measured blood loss were either accepted causes of PPH (uterine atony, perineal laceration) or known risk factors for complicated vaginal deliveries (prolonged second stage labor, neonatal head circumference, vacuum deliveries).

Corresponding author: Prof. Christian Haslinger, MD, Division of Obstetrics, University Hospital Zurich, Frauenklinik Str. 10, 8091 Zürich, Switzerland, E-mail: christian.haslinger@usz.ch

Maike Katja Sachs and Elisabeth Kapfhammer contributed equally to this work and share first authorship.

Acknowledgments

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. The authors have no relevant financial or non-financial interests to disclosure.

Research ethics: Study approval was given by the “Ethics Review Board of Zurich” prior to patient enrollment (KEK-ZH 2015-0011).
Informed consent: Written informed consent was obtained from the patients.
Author contributions: MKS: Protocol/project development, study organisation and participant recruitment, data collection, manuscript writing. EK: manuscript writing, manuscript editing, RB: manuscript editing, LK: manuscript writing, NOK: manuscript editing, CH: Protocol/project development, study organisation and participant recruitment, manuscript editing. The initial study outline was designed by CH and MKS contributed to study organization and participant recruitment. MKS collected the data and performed the statistical analyses. MKS, EK and LK wrote the manuscript. All authors participated in the drafting and/or revising of the manuscript and contributed to its publication. All authors read and approved the final manuscript.
Use of Large Language Models, AI and Machine Learning Tools: None declared.
Conflict of interest: The authors state no conflict of interest.
Research funding: None declared.
Data availability: Not applicable.

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Received: 2024-11-26

Accepted: 2025-05-11

Published Online: 2025-05-23

Published in Print: 2025-09-25

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

https://doi.org/10.1515/jpm-2024-0567

Keywords for this article

postpartum bleeding; epidural; anesthesia during delivery

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BY 4.0