One of the core issues facing expecting mothers is planning the type of analgesia to use during labor and birth. Options range from going completely without, to being totally unconscious. Right in the middle is epidural analgesia1 - the "most popular means for pain relief during labor." An "epidural" is asked for by name more than any other method of pain relief and is used by over 50% of women giving birth at hospitals."2

The method is not without controversy, however. The media has reported complications with the procedure "turning deadly,"3 and many naturalists claim the risks have been "greatly underplayed."4 In an attempt to assess current research on the topic, I have collected recent academic publications on the effects and implications of epidural analgesia during labor and birth.

Research by Year

Studies and reviews are listed below by their year of release, ranging from 1996 to 2007. Note that while the general findings are only summarized herein and the full studies should be referenced for details.

1996

Overall Risks / Benefits (Publication Review)

A 1996 review entitled Epidural analgesia in labor: an evaluation of risks and benefits found the practice to be be a "safe and effective method of relieving pain in labor." The risks confirmed included:

• longer labor
• more operative intervention
• higher cost

Other risk associations were identified as tenuous and requiring further study, including:

• maternal fever in labor
• chronic back pain
• neonatal behavioral changes
• maternal-infant bonding5

1998

Pain Relief Effectiveness

A 1998 study entitled Risk factors of inadequate pain relief during epidural analgesia for labour and delivery assessed the causes of epidural failure among patients delivering vaginally. The study found "inadequate pain relief during labor and during delivery were found in 5.3% and 19.7%" of patients, respectively. The risk factors included:

• inadequate analgesia efficacy of the first dose
• posterior presentation6
• radicular pain during epidural placement
• duration of epidural analgesia greater than six hours
• duration of epidural analgesia less than one hour

Based on these, the study concluded simple changes of practice may lead to improved epidural effectiveness.7

Compared to Parental Opioid Analgesia (Publication Review)

Starting from a claimed context of epidural analgesia being associated with high cesarean delivery rates, a 1998 study sought to compare this risk and others to the use of parenteral opioid analgesia.8 The study involved two independent data extractions from ten trials (2369 patients) and found no difference between the two methods concerning:

• instrumented vaginal delivery9 rates for dystocia10
• cesarean delivery rates

It did, however, identify epidural analgesia as correlating with:

• increased rates of instrumental delivery in general
• longer first and second stages of labor11
• lower likelihood of neonate with low 5-minute Apgar scores12
• mothers with lower pain scores in first and second stages of labor
• lower rates of mother dissatisfaction13

2000

Compared to Non-Epidural Analgesia (Publication Review)

A 2000 review widened the scope of the 1998 study to compare epidural analgesia to all other pain relief methods. Eleven studies (3157 women) were included and found epidural analgesia to be associated with:

• greater pain relief
• longer first and second stages of labor
• increased incidence of fetal malposition14
• increased use of oxytocin15
• increased rate of instrumented vaginal deliveries

Concurring with the 1998 review, no statistically significant effect on cesarean section rates was identified.16

2001

Compared to Non-Epidural Analgesia

The author of the 2000 publication review followed up with his own research in a 2001 study entitled A randomised controlled trial of epidural compared with non-epidural analgesia in labour. The study found no significant difference in:

• reported incidence of backache at three months
• reported incidence of backache at twelve months
• maternal satisfaction

It did identify, however, a somewhat higher incident rate of instrumented delivery in the epidural group.17

2002

Compared to Intravenous Analgesia

In the vein of the 1998 review, a 2002 study compared epidural analgesia to an alternative method, this time intravenous analgesia. The study found epidural analgesia, when compared to intravenous analgesia, to:

• provide better pain relief
• have fewer adverse effect
• cost more (including hospital base-line fees and incremental care costs)18

Obstetric Lacerations

A study entitled The effect of epidural analgesia on the occurrence of obstetric lacerations19 and on the neonatal outcome during spontaneous vaginal delivery found epidural analgesia to be a "safe and effective method of pain relief during labour." The following risk associations were found, although it was noted they could be due to the higher rate of primiparous women using epidural analgesia:

• prolonged second stage of labor
• higher rate of episiotomy20
• increased use of oxytocin

No "evidence of a detrimental effect on the integrity of the birth-canal in spontaneous vaginal delivery" was found.21

Long Term Effects vs Non-Epidural Analgesia

The same researcher involved in the 2000 review and 2001 study published a study also in 2002 on the effects of epidural analgesia on long-term backache as compared to non-epidural analgesia. The patients (369 women) were interviewed concerning their back pain an average of 26 months after delivery. The study found no significant differences between women who receive epidural pain relief and women who receive other forms of pain relief as concerning:

• incidence of long term low back pain
• disability
• movement restriction22

Fetal Acid-Base Balance

A 2002 study aimed to determine the effect of epidural analgesia on funic acid-base status23 at birth, as compared to systemic labor analgesia. Studying babies of 2102 mothers in five countries, it found epidural analgesia to be "associated with improved neonatal acid-base status, suggesting that placental exchange is well preserved in association with maternal sympathetic blockade and good analgesia." The conclusion claims the following negative effects of epidural analgesia are outweighed by the benefits to neonatal acid-base status:

• maternal hypotension and fever
• longer second stage of labour
• more instrumental vaginal deliveries24

Patient-Controlled vs Continuous Infusion (Publication Review)

This 2002 review compared the safety and effectiveness of two epidural analgesia application methods: patient-controlled epidural analgesia (PCEA)25 and continuous epidural infusion (CEI).26 The review included nine studies (640 patients) and found both methods of epidural analgesia administration to be safe for mother and newborn. Patients receiving PCEA were found to (as compared to those receiving CEI):

• have fewer anesthetic interventions
• receive less local anesthetic
• receive less monitor block27

2003

Compared with Combined Spinal-Epidural (Publication Review)

Combined spinal-epidural (CSE)28 was introduced in an attempt to reduce the adverse effects of traditional epidural analgesia, listed as:

• prolonged labor
• use of oxytocin augmentation
• increased incidence of instrumental vaginal delivery

This 2003 study evaluates the effectiveness of CSE by looking at maternal satisfaction. The review included nineteen trials (2658 women) and found there to be little difference between CSE and other forms of epidural for pain relief in labor. The conclusions state CSE:

• provides faster onset of effective pain relief from the time of injection
• increases the incidence of maternal satisfaction
• causes more itching

There is no difference between CSE and other epidural techniques with respect to the incidence of:

• forceps delivery
• maternal mobility
• postdural puncture headache (PDPH)29
• cesarean section rates
• admission of babies to the neonatal unit30

2004

Safety and Effectiveness (Publication Review)

A 2004 review entitled Epidural analgesia for pain relief in labour and childbirth - a review with a systematic approach assessed twenty-four articles with respect to the procedure's safety and effectiveness. It found "the use of epidural analgesia is considered to be an effective method of pain relief during labour and childbirth from the perspective of women giving birth. ... Midwives and doctors can recommend this form of pain relief."31

Discontinuation Late in Labor (Publication Review)

Another 2004 review ascertained the consequences of discontinuing epidural analgesia late in labor in order to avoid possible negative consequences associated with the pain relief technique. The review of six studies found when the epidural analgesia was discontinued there was:

• no statistically significant reduction in instrumental delivery rate, nor in any other delivery outcome rates
• a significant increase of reported inadequate pain relief32

Breast-Feeding Problems

This study investigated breast-feeding problems after epidural analgesia administration during labor. The results of a survey of primiparae33 associated partial breast-feeding or formula feeding during the first 12 weeks with:

• older age of the mother
• use of epidural analgesia
• problem of "not having enough milk" (reported more often by those who had received epidural analgesia)

The following were found not to have any association with the failure to breast-feed fully:

• cesarean section
• other methods of labor analgesia
• other breast-feeding problems

The study stops short of claiming a causal relationship between epidural analgesia and breast-feeding problems, however.34

Prophylactic Intravenous Preloading (Publication Review)

This 2004 review of six studies (473 participants) investigated the effects of prophylactic intravenous preloading.35 It found preloading may have some "beneficial fetal and maternal effects in healthy women" prior to traditional high-dose local anaesthetic blocks. There was no identifiable benefit for low-dose epidural or CSE analgesia techniques, however.36

First-Stage Ambulation (Publication Review)

This review of five trials (1161 women) evaluated the effects of first-stage ambulation,37 as there were a number of new techniques for administering epidural analgesia allowing increased mobility for birthing women. The review found there to be no statistically significant difference between women with an epidural who ambulated in the first stage of labour and those who remained recumbent in the following areas:

• mode of delivery (e.g., instrumental, cesarean, etc.)
• use of oxytocin augmentation
• duration of labor
• satisfaction with analgesia
• Apgar scores38

Cesarean Section and Instrumental Vaginal Delivery Rates (Publication Review)

This review compared the effects of low-dose epidural infusions of bupivacaine39 with parenteral opioid analgesia, specifically targeting the resulting rates of cesarean sections and instrumental vaginal deliveries. The results showed epidural analgesia is associated with the following, as compared to parenteral opioid analgesia:

• increased risk of instrumental vaginal delivery
• longer second stage of labor
• better pain relief

It was not associated with an increased risk of cesarean section.40

2005

Compared to Non-Epidural or No Analgesia (Publication Review)

A 2005 study comparing epidural versus non-epidural or no analgesia during labor grouped 21 studies (6664 women) and identified the method as effective. Epidural analgesia administration was found not to be associated with:

• risk of cesarean section
• maternal satisfaction with pain relief
• long-term backache
• Apgar scores

It was, however, found to correlate with an increased risk of instrumented vaginal birth.41

Neurobehavioral and Breast-Feeding Effects

Another 2005 study investigated a possible association between epidural analgesia during labor/delivery, infant neurobehavioral status, and effective breast-feeding. The results found no significant difference between the epidural analgesia and no-analgesia groups in:

• breast-feeding effectiveness at 8-12 hours
• infant neurobehavioral status at 8-12 hours
• the proportion of mothers continuing to breast-feed at 4 weeks42

2006

Self-Hypnosis (Publication Review)

A 2006 review of trials studying complementary and alternative pain management therapies in 2006 identified effects on the need for epidural analgesia specifically. The review included fourteen trials (1537 women) and found women taught self-hypnosis:

• had decreased requirements for pharmacological analgesia including epidural analgesia
• were more satisfied with their pain management in labor43

2007

Stress Urinary Incontinence

A 2007 study investigated a possible correlation between epidural analgesia and stress urinary incontinence (SUI),44 but found none. It did, however, confirm increased risks of:

• prolonged labor
• instrumental delivery
• cesarean delivery
• longer first stage of labor (when analgesia was administered early)45

Summary

The results/conclusions of the above studies and reviews are summarized below as risks, benefits, and other. Risks and benefits are noted with the year of the commenting studies in parentheses, along with a "+" or "-" indicating whether the study confirms or dispels the listed association.

Risks

The publications discussed in this article commented on the following risks of epidural analgesia:

• longer labor (+1996, +1998, +2000, +2004, +2007)
• cesarean delivery (-1998, -2000, -2004, -2005, +2007)
• instrumented vaginal delivery (+1996, +1998,46 +2000, +2001, +2004, +2005, +2007)
• higher cost (+1996, +2002)
• inadequate pain relief (-1998)
• fetal malposition (+2000)
• use of oxytocin (+2000, +2002, -2004)
• long term backache (-2001, -2002, -2005)
• spinal mobility / disability (-2002)
• neonatal behavioral issues (-2005)
• breast-feeding problems (+2004, -2005)
• lower Apgar scores (-2005)
• birth-canal integrity (-2002)
• episiotomy rate (+2002)
• stress urinary incontinence (-2007)

Benefits

The publications discussed in this article commented on the following benefits of epidural analgesia:

• higher Apgar scores (+1998, -2005)
• mother pain relief (+1998, +2000, +2002, +2004)
• mother satisfaction (+1998, -2001, -2005)
• funic acid-base status (+2002)

Other notes

In addition to risks and benefits, the following notes/claims were made in the above studies concerning epidural analgesia:

• PCEA has benefits over CEI. (2002)
• CSE has benefits over traditional epidural analgesia. (2003)
• Discontinuing epidural analgesia late in labor increases pain and does not reduce risk of instrumented delivery. (2004)
• Preloading has benefits over a traditional high-dose local anaesthetic block. (2004)
• Ambulation in the first stage of labor has no positive or negative affect among those having received epidural analgesia. (2004)
• Alternative methods such as self-hypnosis lower the need for epidural analgesia. (2006)

Conclusions

In general, the studies/reviews analyzed indicate epidural analgesia as an effective means of pain relief during childbirth. The undisputed risks seem to be a longer labor, greater cost and higher chance of instrumented vaginal delivery, while the undisputed benefit found is effective pain relief.

Other Labor Pain Relief Studies

The following is an assortment of other interesting studies concerning labor pain relief, listed by general topic and including a brief summary of the findings:

• Water Immersion - "There is evidence that water immersion during the first stage of labour reduces the use of analgesia and reported maternal pain, without adverse outcomes on labour duration, operative delivery or neonatal outcomes."47
• Hynotherapy - "Women who were prepared with the hypnoreflexogenous method had significantly less fear and pain, required significantly less analgesia, had a shorter period of labour and delivery and recovered faster from labour."48
• Continuous Support During Childbirth - "Women who had continuous intrapartum support were less likely to have intrapartum analgesia, operative birth, or to report dissatisfaction with their childbirth experiences. ... In general, continuous intrapartum support was associated with greater benefits when the provider was not a member of the hospital staff, when it began early in labour, and in settings in which epidural analgesia was not routinely available."49
• Position in Second Stage of Labor - While concluding "[w]omen should be encouraged to give birth in the position they find most comfortable," this study found the use of any upright or lateral position, compared with supine or lithotomy positions, was associated with:
  • reduced duration of second stage of labor
  • a small reduction in assisted deliveries
  • a reduction in episiotomies
  • an increase in second degree perineal tears
  • increased estimated blood loss greater than 500 ml
  • reduced reporting of severe pain during second stage of labor
  • fewer abnormal fetal heart rate patterns50
• Effects of Psychosocial Support During Labor and Childbirth - "Psychosocial support by doulas had a positive effect on breastfeeding and duration of labour. It had a more limited impact on medical interventions, perhaps because of the strict routine in hospital procedures, the cultural background of the women, the short duration of the intervention, and the profile of the doulas. It is important to include psychosocial support as a component of breastfeeding promotion strategies."51

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