NEURAXIAL LABOR ANALGESIA
From the 59th Annual Postgraduate Assembly in Anesthesiology, presented December 9-13, 2005, by the New York
State Society of Anesthesiologists
| MODE OF DELIVERY: IS IT INFLUENCED BY LABOR ANALGESIA? —Joy L. Hawkins, MD, Professor of Anesthesiology
and Director of Obstetric Anesthesia, University of Colorado School of Medicine, Denver
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| Background for concerns: maternal complications higher with cesarean delivery; perineal injuries to mother more likely
with forceps or vacuum-instrumented delivery; fecal incontinence strongly correlated with perineal injuries; birth injuries
to fetus more common if mother has assisted vaginal delivery
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| Difficulties in studying effects of labor anesthesia: no placebo group (unethical not to give analgesia; usually receive
parenteral narcotics); high crossover rates between groups (patients in epidural group may have rapid labor and not get
epidural, or patients may request analgesia when not in epidural group); cesarean delivery rates vary widely; length of
labor difficult to define because hard to define onset of labor and when second stage of labor starts; techniques and
concentrations of solution differ (eg, intrathecal fentanyl vs 0.125% bupivacaine); blinding of study impossible; difficult
to hold obstetric practice static; patients with more pain in early labor more likely to need cesarean delivery
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| Research: studies provide evidence that regional anesthesia does not negatively affect delivery outcome in spontaneously
laboring patients; Tripler Army Medical Center (1992)—United States Department of Defense mandated that
all military hospitals that provide obstetric care must have analgesia service that could provide epidurals (5000 deliveries
per year; before mandate, Tripler Army Medical center had epidural rate of 1%; 1 yr after mandate, epidural rate
84%); comparison between 2 groups showed no difference in cesarean delivery rates, forceps delivery rates, vacuum-
assisted delivery rates, or change in first stage of labor; study concluded that introducing epidural service does not
change outcome of labor; second stage of labor increased by ≈25 min; trial—several hundred women having first
baby randomized to epidural or intravenous (IV) patient-controlled analgesia (PCA) with fentanyl; study showed no
difference in cesarean delivery or forceps delivery rates; second stage of labor 23 min longer in epidural group; pain
and satisfaction scores better in epidural group; mothers in IV PCA group sleepier and more nauseated, and pediatricians
more likely to have to do active resuscitation on their babies; study—ongoing; patients randomized to epidural
or IV meperidine; review looking at 3000 patients showed no difference in cesarean delivery rates; epidural group had
more oxytocin use, longer first and second stages of labor, and more forceps deliveries (forceps deliveries common in
this hospital); fever more common in epidural group; study of patients with preeclampsia—patients randomized to
epidural or IV opioids; study showed no difference in cesarean delivery rates; epidural group needed more ephedrine
(hypotension); newborns from mothers in epidural group needed less naloxone; no difference in preeclampsia-related
complications; systematic review—7 randomized controlled trials comparing low-dose epidural infusions to
parenteral opioids; data showed low-concentration epidural infusions unlikely to change risk for cesarean delivery;
epidural groups showed some association with increased risk for forceps delivery (institution-dependent); epidural analgesia
associated with longer second stage of labor and oxytocin use (relevance unclear); maternal and baby outcomes
better when woman randomized to epidural group rather than parenteral opioid
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| Severe pain in early labor: high-risk group for cesarean delivery for dystocia; 2 studies where women in spontaneous labor
or in separate study, women induced with oxytocin (all <5 cm dilated) randomized to nalbuphine or epidural; no
difference in cesarean delivery rates in either study; women with epidural had better pain relief; cord gases in nalbuphine
group more acidemic; Tripler Army Base study—looked at women who had analgesia (IV or epidural) begun
when <4 cm dilated; no difference in cesarean delivery rate; study—750 women having first baby randomized to intrathecal
fentanyl (25 µg) and epidural infusion later or IV hydromorphone (Dilaudid); pain scores lower in those who
got spinal fentanyl; rates of cesarean delivery not different; women who got intrathecal fentanyl had significantly faster
labors than those who got IV opioid; newborn outcome worse in parenteral narcotic group; intrathecal sufentanil
study—patients (<5 cm dilated) randomized to spinal sufentanil or epidural; study showed patients who got spinal narcotic
dilated significantly faster than those who got conventional epidural; conclusions—labor duration potentially
shortened when intrathecal narcotics used (early finding); newborn acid/base status potentially improved using neuraxial
techniques; pain scores decreased with neuraxial analgesia; mothers not groggy and vomiting; evidence that unnecessary
to withhold neuraxial analgesia until later in labor
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| Ambulation: common suggestion to help keep women from being affected by analgesia techniques during labor (not supine
for duration of labor); no evidence to support claim that it helps; safe as long as precautions taken; midwifery literature
states if women walk during labor, they have shorter labor, less pain, less need for oxytocin, and babies look
better; study—patients randomized to walking or not walking (irrespective of use of epidural) showed no difference
between 2 groups; difficult to get women in ambulatory group to walk; study with epidural—every patient had epidural
and randomized to walk or not walk; found no difference in time from epidural placement to complete dilatation; another
study had similar results, but showed patients who walked used less bupivacaine; patients liked being able to get
up and use bathroom; safety study—150 patients (50 not pregnant, 50 at term [not in labor], and 50 in labor who got
spinal anesthetic); data collected from women on Balance Master doing various tasks; data showed being pregnant
made women fall over, regardless of anesthetic (center of gravity changes); ambulation protocol in hospital—requires
that labor, mother, and fetus all considered low-risk; test for motor block (shallow knee bend); ask mother how she
feels; requires accompaniment by someone during ambulation; test orthostatics; follow American College of Obstetrics
and Gynecology (ACOG) guidelines for intermittent fetal monitoring
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| Counseling patient: choice of epidural or IV opioids will not change risk for cesarean delivery, although second stage of
labor potentially 0.5 hr longer; with choice of IV opioids, incidence of nausea higher and mother potentially sleepier;
risk to baby less with epidural; informed choices about potential treatment of pain during labor and how treatment affects
her and baby
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| Obstetric concerns: fetal head position—question whether use of epidural increases chances of baby’s head occiput
posterior (OP) or occiput transverse (OT) and why second stage of labor longer; difficult to study; Tripler Army Base
looked at incidence of OP position before and after epidurals and found no difference between 2 periods; 2 randomized
studies in obstetric literature did not show increased risk for fetal malposition (treatment crossover rate in study
high; difficult to draw conclusions); study done using perineal ultrasonography throughout labor (unrelated to whether
patient going to receive epidural) looking at head position showed that mothers who ultimately had epidural 4 times
more likely to end up with baby in OP position; perineal injury— studies found that use of epidural increases risk for
use of forceps; forceps use increases third- and fourth-degree perineal lacerations; lacerations associated with increased
risk for fecal incontinence; studies difficult to do (obstetricians’ skill and comfort with forceps vary; indications
vary widely)
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| Conclusions: length of labor increased by ≈30 min when epidural used; malposition of fetal head potentially increased
with use of epidurals (no strong evidence); in institutions where forceps deliveries accepted, increased incidence of
forceps deliveries by using epidural analgesia (more perineal injuries and subsequent maternal morbidity); cesarean
rates no different with epidural analgesia, intrathecal analgesia, or parenteral opioid analgesia
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| EFFECTS ON NEWBORN BEHAVIOR AND THE IMPACT ON BREAST-FEEDING —Yaakov Beilin, MD, Associate
Professor of Anesthesiology, Obstetrics & Gynecology and Reproductive Science, Co-Director, Obstetric Anesthesia,
Mount Sinai School of Medicine, New York, NY
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| Transfer of drugs: drugs of concern cross placenta by simple diffusion; Fick’s equation (concentration of drug that
crosses per unit time relates to [diffusion constant (K) multiplied by amount of medication on maternal side] minus
[concentration of medication on fetal side divided by area of placenta]); diffusion constant important (related to molecular
weight [higher weight less likely to cross], lipid solubility of molecule [more lipid soluble medication, more
likely to cross], and degree of ionization)
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| Neuraxial medications: local anesthetics and opioids (top 2); clonidine, neostigmine, and ketamine (all used in research
protocols); local anesthetics—cross placenta (minimal placental transfer; highly protein-bound; not very lipid-soluble);
amount increases in fetal acidosis (ion trapping; unionized drug crosses); opioids—lipid-soluble; cross placenta easily;
negative effects on fetus (fetal liver metabolism slower; neonate more sensitive to central nervous system effects than
mother)
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| Assessment of baby: during labor—fetal heart rate; scalp pH; after delivery—Apgar score; umbilical cord pH; neurobehavioral
assessment (not routinely done, usually only if something wrong with baby); neurobehavioral
assessment—assess subtle effects of drugs on behavior; Brazelton Neonatal Behavioral Assessment Scale (NBAS);
Early Neonatal Neurobehavioral Scale (ENNS); Neurologic and Adaptive Capacity Score (NACS); NBAS and ENNS
developed first, but take long time to use and rely on noxious stimuli; NACS (1982)—differentiates drug effect from
other causes; easy to use, requires little training, quick, and noninvasive; consists of 20 maneuvers and evaluates 5
general areas (adaptive capacity, passive tone, active tone, primary reflexes, and general assessment); test scored 0, 1,
or 2, with maximum score of 40; if score <35, neonate considered depressed; reliability and validity questioned; some
studies show that in babies exposed to anesthetic, NACS scores slightly depressed, compared to babies not exposed to
anesthesia; Food and Drug Administration (FDA) requires that all medications used in clinical arena have minimal effects
on neonatal neurobehavior
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| Clinical significance of lower neurobehavioral score: question whether breast-feeding depressed; breast-feeding—
considered best source of nutrition; early breast-feeding required for ultimate success; currently, breast-feeding rate at
36% (goal 50% by 2010); pilot study—purpose to assess whether epidural fentanyl has effect on breast-feeding;
showed no difference in nulliparous women; however, in multiparous women who had vaginal deliveries and had
breast-fed before, of those who received smaller dose of fentanyl (<150 µg), 35% reported some problem with breast-
feeding and of those who received >150 µg, 65% reported problems; prospective randomized study—multiparous
women who breast-fed before with planned vaginal deliveries divided into 3 groups (no epidural fentanyl, <150 µg
epidural fentanyl, and >150 µg epidural fentanyl); umbilical vein blood drawn to check for fetal fentanyl levels; Apgar
scores; neurobehavioral scores (NACS) done 24 hr after delivery; maternal assessment of breast-feeding; lactation
consultant’s assessment of breast-feeding; follow-up 6 wk postpartum to find out if mother still breast-feeding and if
not, whether related to neonatal or maternal concerns (not considered failure); findings—amount of fentanyl found in
umbilical cord greater as amount given increased; no difference in umbilical cord bupivacaine levels; NACS scores
lowest in babies whose mothers received higher dose of fentanyl dose; at 24 hr, more mothers reported having trouble
breast-feeding in group receiving higher fentanyl dose, but not statistically significant; at 6 wk, 20% of patients in
highest fentanyl group still not breast-feeding vs lower rate in other groups (statistically significant); conclusion that in
this group of patients, epidural fentanyl does affect ultimate success rate at 6 wk of breast-feeding; study limitations
include limited number of patients, no nulliparous patients, crossover between groups, patients lost to follow-up, and
mechanism of problem not addressed in study; theory that fentanyl crossed placenta; other variables known to cause
problems with breast-feeding include duration of labor, type of delivery, coexisting maternal diseases, and maternal
and paternal attitudes toward breast-feeding
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| Implications: no need to change protocols at present; consider alternatives before changing protocols; alternatives—
stop using epidurals and use IV analgesia (not appropriate because IV opioids cross placenta to much greater degree
than epidural opioids); stop using epidural opioids or use less of them, thus increasing concentrations of bupivacaine
(safer to use lower concentrations of local anesthetics; higher concentrations may affect obstetric outcome; patient satisfaction
higher with use of lower concentration of local anesthetic); maternal education important
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| Conclusion: epidural fentanyl probably has some impact on neurobehavior and breast-feeding (amount still needs to be
determined); protocols should not change at this time; further study on mechanism necessary
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Educational Objectives
| The goal of this program is to provide the listener with information on the effects of neuraxial labor analgesia on mode
of delivery, newborn neurobehavior, and breast-feeding. After hearing and assimilating this program, the clinician will
be better able to:
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 | 1. Recognize why there is concern about effects of neuraxial analgesia on mode of delivery.
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| 2. Describe why it is difficult to study the effects of labor analgesia.
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| 3. Discuss the impact of neuraxial analgesia on cesarean delivery rates, length of labor, and forceps delivery rates.
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| 4. Explain concerns about labor analgesia and neonatal neurobehavioral outcomes.
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| 5. Discuss effects of neuraxial medications on breast-feeding.
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Discussed on This Program
Bupivacaine HCl [several trade names]
Clonidine HCl [Catapres, Duraclon]
Ephedrine sulfate [Pretz-D]
Fentanyl [Sublimaze]
Hydromorphone HCl [Dilaudid, Dilaudid-5, Dilaudid-HP, Palladone]
Ketamine HCl [Ketalar]
Levobupivacaine HCl [Chirocaine]
Meperidine HCl [Demerol]
Nalbuphine HCl [Nubain]
Naloxone HCl [Narcan]
Neostigmine methylsulfate [Prostigmin]
Oxytocin [Pitocin]
Ropivacaine HCl [Naropin]
Sufentanil citrate [Sufenta]
Suggested Reading
Bilin Y, et al: Effect of labor epidural analgesia with and without fentanyl on infant breast-feeding: a prospective, randomized,
double-blind study. Anesthesiology 103:1211, 2005; Birnbach DJ, et al: Neurologic complications of neuraxial
analgesia for labor. Curr Opin Anaesthesiol 18:513, 2005; Bolukbasi D, et al: Comparison of maternal and neonatal
outcomes with epidural bupivacaine plus fentanyl and ropivacaine plus fentanyl for labor analgesia. Int J Obstet Anesth
14:288, 2005; Chang ZM, Heaman MI: Epidural analgesia during labor and delivery: effects on the initiation and continuation
of effective breastfeeding. J Hum Lact 21:305, 2005; Decca L, et al: Labor course and delivery in epidural analgesia:
a case-control study. J Matern Fetal Neonatal Med 16:115, 2004; Halpern SH, Ioscovich A: Epidural analgesia
and breast-feeding. Anesthesiology 103:1111, 2005; Halpern SH, et al: A multicenter randomized controlled trial comparing
patient-controlled epidural with intravenous analgesia for pain relief in labor. Anesth Analg 99:1532, 2004; Lieberman
E, et al: Changes in fetal position during labor and their association with epidural analgesia. Obstet Gynecol
105:974, 2005; Liu EHC, Sia ATH: Rates of caesarean section and instrumental vaginal delivery in nulliparous women
after low concentration epidural infusions or opioid analgesia: a systematic review. BMJ 328:1410, 2004; Missant C, et
al: Patient-controlled epidural analgesia following combined spinal-epidural analgesia in labour: the effects of adding a
continuous epidural infusion. Anaesth Intensive Care 33:452, 2005; Nikkola E, et al: Patient-controlled epidural analgesia
in labor does not always improve maternal satisfaction. Acta Obstet Gynecol Scand 85:188, 2006; Radzyminski
S: Neurobehavioral functioning and breastfeeding behavior in the newborn. J Obstet Gynecol Neonatal Nurs 34:335,
2005; Salim R, et al: Continuous compared with intermittent epidural infusion on progress of labor and patient satisfaction.
Obstet Gynecol 106:301, 2005; Wong CA, et al: A randomized comparison of programmed intermittent epidural
bolus with continuous epidural infusion for labor analgesia. Anesth Analg 102:904, 2006; Wong CA, et al: The risk of
cesarean delivery with neuraxial analgesia given early versus late in labor. N Engl J Med 352:655, 2005; ACOG Committee
Opinion #295: pain relief during labor. Obstet Gynecol 104:213, 2004.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial
relationship with the manufacturer or provider of any commercial product or service discussed. For this issue, the
faculty reported nothing to disclose.
Drs. Beilin and Hawkins were recorded at the 59th Postgraduate Assembly in Anesthesiology, held December 9-13,
2005, in New York, NY, and sponsored by the New York State Society of Anesthesiologists, Inc. The Audio-Digest
Foundation thanks the speakers and the sponsor for their cooperation in the production of this program.
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