Evidence-Based Analysis of Detriments Associated with Epidural Analgesia and Labor Medications

Executive Summary

Pharmacological interventions for pain relief and labor augmentation, such as epidural analgesia and opioid analgesics, are widely utilized in modern obstetrics. While these interventions offer significant benefits in managing labor and delivery, recent evidence highlights a range of associated detriments for both the birthing parent and the newborn. These detriments span prolonged labor, increased risk of operative delivery, various maternal physiological side effects, altered newborn behavior, and challenges with breastfeeding initiation and duration. A recurring theme across these interventions is their potential to disrupt natural physiological processes, leading to a cascade of effects that can compound risks. Understanding these evidence-based detriments is crucial for facilitating truly informed decision-making in maternity care.

Introduction

The landscape of modern obstetrics frequently incorporates pharmacological interventions to manage the inherent pain and physiological demands of labor and birth. Epidural analgesia and various opioid analgesics are common components of contemporary childbirth practices. While these medical tools are invaluable in specific clinical scenarios, their widespread application necessitates a thorough understanding of their potential adverse effects.

This report aims to synthesize recent, evidence-based research concerning the detriments associated with epidural analgesia and opioid analgesics during labor, birth, and the postpartum period, including their impact on breastfeeding. By providing direct textual evidence and citations from peer-reviewed literature, this analysis seeks to equip healthcare providers and expectant parents with comprehensive information to support informed decision-making regarding labor pain management and augmentation strategies. The objective is to delineate the effects on maternal well-being, labor progression, neonatal health, and breastfeeding outcomes, highlighting the intricate interconnections between these interventions and their physiological consequences.

Detriments of Epidural Analgesia

Epidural analgesia, a common method for pain relief during labor, is associated with several adverse effects impacting maternal labor progression, physiological responses, fetal health, and breastfeeding outcomes. The following table summarizes these key detriments before a more detailed discussion.

Table 1: Summary of Epidural Analgesia Detriments

Detriment	Key Impact	Affected Area
Prolonged Labor Stages	Increased duration of first and second stages of labor	Maternal Labor Progression
Increased Risk of Operative Delivery	Higher likelihood of instrumental vaginal birth (forceps/vacuum) or C-section	Maternal Labor Outcome
Maternal Hypotension	Significant drop in blood pressure, potentially affecting fetal heart rate	Maternal Physiological Response
Fetal Heart Rate Changes	Worsening fetal heart rate category, bradycardia	Fetal Health
Delayed Onset of Lactation	Slower "milk coming in" postpartum	Breastfeeding Initiation
Altered Newborn Behavior	Decreased suckling ability, altered instinctive behaviors	Newborn Behavior & Breastfeeding
Perineal Trauma	Higher risk of severe perineal tears	Maternal Postpartum Recovery
Postpartum Hemorrhage & Fever	Increased risk of excessive bleeding and maternal infection	Maternal Postpartum Complications
Back Pain & Headache	Common maternal side effects post-procedure	Maternal Discomfort

3.1. Impact on Labor Progression and Outcomes

Epidural analgesia has been consistently linked to a longer duration of labor. Studies have shown that the first stage of labor can be prolonged by approximately 61 minutes and the second stage by about 43 minutes when epidural analgesia is used.¹ Early initiation of epidural analgesia, particularly at cervical dilation up to 3 cm, is specifically associated with a prolonged second stage and overall labor duration.¹ A meta-analysis published in 2020, which combined 13 observational studies representing over 337,000 births, found that individuals who received an epidural during labor had five times the odds of experiencing a prolonged second stage of labor.² A more recent 2023 study from China also observed a longer second stage in the epidural group (79 minutes on average) compared to the non-epidural group (57 minutes).²

The prolongation of labor stages, particularly the second stage, is not merely a matter of duration; it carries significant implications for the mode of delivery. A prolonged second stage of labor, often a consequence of epidural use, is linked to a higher risk of requiring instrumental assistance, such as forceps or vacuum extraction, or a cesarean delivery.² The 2020 meta-analysis noted that a prolonged second stage led to five times the odds of needing a vacuum or forceps-assisted birth.² Furthermore, worsening fetal heart rate categories observed after epidural administration have been independently associated with an increased risk for cesarean delivery.³ Large cohort studies have consistently demonstrated a positive association between epidural analgesia and cesarean delivery rates. For instance, a Slovenian study reported a significantly higher cesarean delivery rate with epidural analgesia (13.3% vs 10.1%), and a Danish study found a higher risk for emergency cesarean delivery (aOR, 5.8) with epidural analgesia.³

The physiological mechanism underlying these prolonged labor stages and increased interventions is rooted in the epidural's action. Epidurals numb or decrease sensations from nerves on the cervix and pelvic tissues.² These nerves are integral to the utero-pituitary reflex, a positive feedback loop where pressure on the cervix stimulates the pituitary gland to produce more oxytocin, which, in turn, strengthens uterine contractions.² By interrupting this reflex, epidurals can diminish the effectiveness or strength of uterine contractions, thereby weakening pushing efforts and leading to a less efficient pushing phase and a prolonged second stage of labor.² This extended labor duration is a known risk factor for a cascade of adverse maternal outcomes, including a higher risk of maternal infection, severe perineal tears, postpartum hemorrhage, and postpartum fever.² This sequence illustrates a clear physiological pathway from the initial intervention to multiple downstream complications.

Moreover, if epidurals weaken contractions and prolong labor, the clinical response often involves the administration of synthetic oxytocin (Pitocin) to augment contractions.² This is why sometimes with an epidural or spinal, you will often see synthetic oxytocin, known as Pitocin or Syntocinon, given through an IV, to try and counteract this lower production of your own natural oxytocin. A synthetic oxytocin and your own endogenous oxytocin are a little bit different. The oxytocin that is made synthetically and given through your IV cannot cross the blood-brain barrier, so it does not have those natural pain-relieving effects.² This potential for a compounding effect on the overall risk profile further alters the physiological birth process.

3.2. Maternal Physiological Side Effects

Maternal hypotension, a decrease in blood pressure, is a common side effect of epidural analgesia. This is defined as a drop in maternal systolic blood pressure to below 90 mm Hg or a reduction of more than 20% from the pre-epidural value.³ In one study, severe maternal hypotension occurred in 36.2% of participants.³ This decrease in blood pressure can, in turn, slow the baby's heart rate, necessitating intravenous fluids and sometimes medication to maintain blood pressure.⁵

While generally minor and transient, some women experience soreness at the epidural injection site in the lower back, which typically resolves within a few days.⁵ On rare occasions, the needle may pierce the covering of the spinal cord, leading to a post-dural puncture headache that can be debilitating if left untreated.⁵

The occurrence of maternal hypotension is not merely a discomfort for the birthing parent; it serves as a significant mediating factor in fetal distress. A drop in maternal blood pressure directly reduces blood flow to the placenta, which can lead to fetal bradycardia and worsening fetal heart rate categories.³ This compromise to fetal well-being then independently increases the risk for cesarean delivery.³ This highlights a direct physiological connection where a maternal side effect has immediate and critical implications for the fetus and the ultimate mode of delivery.

3.3. Fetal and Neonatal Impacts

Epidural analgesia can lead to notable changes in the fetal heart rate (FHR), including worsening categories and bradycardia. These FHR changes are a significant concern as they can indicate fetal compromise.³ In one study, a worsening fetal heart rate category occurred in 11.4% of participants within 60 minutes of epidural administration and was independently associated with recourse to cesarean delivery.³ A retrospective study documented fetal bradycardia in 11% of cases, with a peak incidence 5 to 20 minutes after epidural administration, persisting throughout the 60-minute post-epidural period.³

Beyond physiological changes, exposure to epidural medications, particularly fentanyl, can significantly affect a newborn's instinctive behaviors in the crucial first hour after birth. These impacts include decreases in neurobehavioral scores and altered rates of suckling.⁶ Research indicates that intrapartum exposure to drugs like fentanyl, often used in epidurals, and synthetic oxytocin is associated with altered newborn infant behavior, including suckling, during skin-to-skin contact in the first hour after birth.⁷ Specifically, babies exposed to both fentanyl and synthetic oxytocin were significantly less likely to reach the suckling stage and begin suckling compared to unexposed infants.⁷ A dose-dependent inverse relationship exists between the likelihood of suckling within the first hour and increased amounts of fentanyl exposure, with the proportion of infants suckling decreasing significantly at approximately 150 mcg of fentanyl.⁶

The quantity of medication transferred to the fetus directly influences their immediate post-birth neurological and behavioral readiness. This readiness is crucial for early bonding and successful breastfeeding initiation, which are foundational for long-term infant health and maternal well-being. The detailed analysis of Widström's 9 Stages of newborn behavior reveals that epidural medications can significantly alter a newborn's natural progression through these stages, impacting the birth cry, rest, crawling to the breast, familiarization, and most critically, suckling.⁷ This disruption of innate behaviors can have immediate consequences for the infant's ability to self-attach and initiate breastfeeding, potentially requiring more intervention and affecting the natural development of the mother-baby dyad.

3.4. Impact on Breastfeeding

Mothers who receive labor pain medications, including epidural analgesia, are more likely to experience a delayed onset of lactation (DOL), defined as milk "coming in" more than three days postpartum.⁸ This association holds true regardless of the delivery method. For instance, compared to women who delivered vaginally with no labor pain medication, those who received spinal/epidural only had an adjusted odds ratio (aOR) of 2.05 for DOL, and those with spinal/epidural plus another medication had an aOR of 1.79.⁸ The highest odds for DOL were observed in women undergoing an emergency cesarean section with spinal/epidural plus another medication (aOR 3.03).⁸

Beyond delayed onset, epidural use has been associated with difficulties in establishing breastfeeding and potentially shorter breastfeeding duration.⁸ This is partly attributed to the impact on the infant's suckling behavior and a decrease in maternal plasma oxytocin levels, which are essential for the milk ejection reflex and milk removal.⁸ In a study of breastfeeding mothers, 21% of those who received an epidural fentanyl dosage greater than 150 mcg during labor reported more difficulty establishing breastfeeding at 24 hours postpartum, compared to 10% of mothers who received a lower dosage or no fentanyl. This higher-dose group also showed a greater likelihood of discontinuing breastfeeding by six weeks postpartum.⁹

The evidence suggests that epidural analgesia influences breastfeeding through multiple pathways. Firstly, it delays the physiological onset of lactation.⁸ Secondly, it can decrease maternal plasma oxytocin levels, a hormone crucial for milk ejection.⁸ Thirdly, the medications, particularly fentanyl, can affect the newborn's neurobehavioral state, making them sleepy or less interested in suckling, thereby hindering effective latch and milk transfer.⁶ These combined effects create a challenging environment for establishing successful breastfeeding, potentially leading to earlier cessation and impacting long-term infant and maternal health outcomes.

Detriments of Opioid Analgesics (e.g., Fentanyl, Pethidine)

Opioid analgesics are sometimes used for pain relief during labor. However, their administration can lead to specific detriments for the mother, particularly those with Opioid Use Disorder (OUD), as well as significant impacts on the newborn's physiology and behavior, and breastfeeding outcomes.

Table 3: Summary of Opioid Analgesics Detriments

Detriment	Key Impact	Affected Area
Newborn Drowsiness/Respiratory Depression	Baby is sleepy, "out of it," or has breathing difficulties	Newborn Health
Altered Newborn Behavior & Suckling	Decreased interest in breastfeeding, reduced readiness to feed	Newborn Behavior & Breastfeeding
Delayed Lactation	Pethidine can affect maternal oxytocin levels, delaying milk production	Breastfeeding Initiation
Fentanyl Transfer to Breastmilk	Fentanyl passes into breastmilk, posing risks to the infant	Breastfeeding Safety
Challenges in OUD Mothers	Higher postpartum pain, concerns about relapse, limited guidelines	Maternal Pain Management
Lower Neurobehavioral Scores (Fentanyl)	Statistically significant but clinically unimportant lower scores	Newborn Neurobehavior
Increased Risk of Bottle Feeding	Dose-related increased risk of formula feeding at hospital discharge	Breastfeeding Duration

4.1. Maternal Considerations

Pregnant individuals with Opioid Use Disorder (OUD) face unique and significant challenges in managing labor and postpartum pain.¹⁰ Factors such as opioid tolerance, opioid-induced hyperalgesia (increased pain sensitivity due to opioid exposure), and concerns about relapse complicate analgesic strategies.¹⁰ This often results in suboptimal pain control and limited analgesic options for this population. Studies indicate that women with OUD report higher pain scores postpartum compared to those without OUD, and they express concerns about inadequate pain control.¹⁰ Healthcare providers also acknowledge the difficulties in balancing effective pain management with the risk of relapse for these individuals. Women maintained on buprenorphine, for example, have been found to experience more pain and require more analgesics after cesarean sections.¹⁰

The data on OUD mothers highlights a significant systemic challenge: a lack of standardized protocols and evidence-based guidelines for pain management in this specific population.¹⁰ This suggests that despite the rising prevalence of OUD, healthcare systems may not be adequately equipped to provide optimal, individualized care, leading to disparities in pain management and suboptimal outcomes. This points to a broader implication for public health and policy, emphasizing the need for targeted research and clinical education to address this vulnerable group's unique needs.

4.2. Newborn Physiological Impacts

Opioid analgesics administered during labor can have a negative effect on a baby's breathing and cause them to be tired or "out of it" shortly after birth.¹¹ Remifentanil, for instance, has a similar impact on the baby as pethidine, potentially slowing initial breathing.¹² Newborns are particularly sensitive to the effects of even small dosages of narcotic analgesics, with maternal use of oral opioids during breastfeeding potentially causing infant drowsiness that can progress to rare but severe central nervous system depression.⁹

Fentanyl, a commonly used opioid, can pass into breast milk, posing risks to the baby.¹³ Infants exposed via breastmilk may exhibit decreased interest in breastfeeding, unusual sleepiness compared to their baseline, breathing difficulties, or limpness.¹³ Immediate medical attention is advised if a baby displays any of these side effects after fentanyl exposure.¹³ Higher doses of epidural fentanyl (e.g., greater than 150 mcg) during labor have been associated with slightly lower neurobehavioral scores in newborns on postpartum day one.⁹ This is likely due to placental transfer of fentanyl before delivery rather than from breast milk after delivery.⁹

The consistent finding that newborns are particularly sensitive to opioids, experiencing effects like respiratory depression and central nervous system depression even at small dosages, underscores the immaturity of the neonatal physiological system, particularly their metabolic and neurological pathways.⁹ This heightened vulnerability means that even seemingly minor maternal exposures can have disproportionately significant impacts on the infant, necessitating careful consideration of opioid use during labor and postpartum, especially when breastfeeding.

4.3. Impact on Newborn Behavior and Breastfeeding

Opioid analgesics, including fentanyl and pethidine, can reduce a newborn's interest in breastfeeding and adversely affect their sucking ability and readiness to feed.¹² Infants whose mothers received pethidine were less willing to initiate breastfeeding.¹⁴ Similarly, babies exposed to both fentanyl and synthetic oxytocin were significantly less likely to reach the suckling stage and begin suckling.⁷

Pethidine can also affect the mother's level of the hormone oxytocin, which may delay the onset of lactation.¹² Furthermore, opioids can make babies sleepy after birth, which can interfere with their normal instinctive behaviors crucial for early bonding and successful breastfeeding.¹² A retrospective study also found a dose-related increased risk of bottle feeding at hospital discharge associated with fentanyl administered during labor.⁹

Opioid analgesics impact breastfeeding through a dual mechanism. Directly, fentanyl can transfer into breastmilk, posing risks to the infant.¹³ Indirectly, and perhaps more pervasively, both fentanyl and pethidine can induce newborn drowsiness and alter crucial instinctive behaviors like suckling and readiness to feed.⁷ This behavioral suppression, combined with potential delays in maternal lactation ¹², creates a significant barrier to successful breastfeeding initiation and continuation, potentially leading to increased reliance on formula feeding.⁹ This highlights how pharmacological interventions can disrupt the delicate, biologically programmed sequence of early mother-infant interactions vital for breastfeeding.

Conclusion

The evidence presented underscores that epidural analgesia and opioid analgesics, while offering crucial pain relief and labor management capabilities, are associated with a range of documented detriments. These adverse effects span maternal labor progression, physiological responses, neonatal health and behavior, and breastfeeding outcomes. A consistent pattern observed is how one intervention can necessitate another, leading to a sequence of effects that potentially compound risks for both the birthing parent and the baby. The disruption of natural physiological processes, particularly hormonal feedback loops and instinctive newborn behaviors, emerges as a central mechanism underlying many of these detriments.

For expectant parents, comprehensive, unbiased, and individualized counseling regarding the potential detriments of these interventions is paramount. Such discussions allow individuals to make truly informed choices about their labor and birth experience, aligning with the "Precautionary Principle" which advocates for rigorous verification of benefits and avoidance of unnecessary interventions.¹⁵

Further research is needed to fully elucidate the long-term neurodevelopmental impacts of specific medications and to develop optimal pain management strategies for vulnerable populations, such as those with Opioid Use Disorder. Ultimately, supporting physiological birth processes where appropriate, and minimizing interventions unless medically indicated, remains a critical approach to optimize outcomes for both mothers and newborns.

Works cited

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2. Effects of Epidurals on the Second Stage of Labor https://evidencebasedbirth.com/effects-of-epidurals-on-the-second-stage-of-labor/

3. Side effects from 10epidural analgesia in laboring women and risk of cesarean delivery  https://pmc.ncbi.nlm.nih.gov/articles/PMC10820310/

4. Maternal and newborn plasma oxytocin levels in response to maternal synthetic oxytocin administration during labour, birth and postpartum – a systematic review with implications for the function of the oxytocinergic system https://pmc.ncbi.nlm.nih.gov/articles/PMC9979579/

5. Epidurals - Benefits & Side Effects of Anesthesia During Labor | MFTM https://madeforthismoment.asahq.org/pain-management/epidural/

6. The Association Between Common Labor Drugs and Suckling When Skin‐to‐Skin During the First Hour After Birth https://pmc.ncbi.nlm.nih.gov/articles/PMC5057303/

7. (PDF) The effect of labor medications on normal newborn behavior https://www.researchgate.net/publication/332789283_The_effect_of_labor_medications_on_normal_newborn_behavior_in_the_first_hour_after_birth_A_prospective_cohort_study

8. Relationship between Use of Labor Pain Medications and Delayed Onset Of Lactation  https://pmc.ncbi.nlm.nih.gov/articles/PMC4684175/

9. Fentanyl - Drugs and Lactation Database (LactMed®) - NCBI https://www.ncbi.nlm.nih.gov/books/NBK501222/

10. Pain Management in Pregnant Women with Opioid Use Disorder: A Systematic Review https://rdw.rowan.edu/stratford_research_day/2025/may1/65/

11. Labor Pain Relief: Options & Side Effects - Cleveland Clinic https://my.clevelandclinic.org/health/articles/4450-labor-pain-relief

12. Labour pain relief: remifentanil | NCT https://www.nct.org.uk/information/labour-birth/pain-labour/labour-pain-relief-remifentanil

13. Fentanyl and Breastfeeding: Is It Safe? https://www.southjerseyrecovery.com/fentanyl/fentanyl-and-breastfeeding/

14. Effect of Maternal Pethidine on Breast Feeding Behavior of Infants https://journalaim.com/FullHtml/aim-15810