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ORIGINAL RESEARCH |
From the Department of Obstetrics and Gynecology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
Address reprint requests to: Rebecca Rogers, MD Department of Obstetrics and Gynecology University of New Mexico Hospital 2211 Lomas Boulevard, NE, ACC-4 Albuquerque, NM 87131 E-mail: becky-roger{at}somasf.unm.edu
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Abstract |
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Methods: The charts of 255 women randomized to active management of labor (n = 125) or control protocols (n = 130) were reviewed and stratified to early epidural placement (up to 4 cm cervical dilatation) versus late placement (more than 4 cm).
Results: Women with early epidural placement had shorter labors than those with late placement (11.6 ± 4.6 versus 13.2 ± 5.6 hours; P = .02). Active management reduced the length of labor compared with controls regardless of epidural timing, with a reduction of 1.4 hours in early epidural placement (10.9 ± 4.7 versus 12.3 ± 4.3 hours; P = .04) and 3.6 hours in those with later placement (11.0 ± 3.6 versus 14.6 ± 6.2 hours; P = .004). Cesarean rates did not vary significantly (early 14.5% versus late 7.9%; P = .21). Early epidural placement did not lengthen the second stage of labor or increase operative vaginal delivery rates.
Conclusion: Early epidural placement did not affect lengths of labor or cesarean rates and was actually associated with shorter labor compared with late epidural placement. Women managed actively in labor, regardless of timing of epidural placement, had shorter labors than controls.
Epidural analgesia may contribute significantly to lengthening labors and increasing cesarean deliveries for dystocia in nulliparas.1–4 Controversy continues over giving epidural analgesia in early labor or when cervical dilatation is more advanced.2,5 Active management of labor, introduced by O’Driscoll et al,6 consistently shortens nulliparous labors.6–9 The current study was a review of 255 nulliparas who requested epidural analgesia and were randomized to active management of labor or a control protocol. Data were stratified to address whether any effects of labor management were dependent on cervical dilatation when epidurals were given, and whether active management of labor shortened labors and reduced cesarean rates among women who requested epidural analgesia as compared with controls.
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Materials and Methods |
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Active management of labor consisted of amniotomy within 2 hours of admission and augmentation of labor with oxytocin if there was not 1 cm dilatation per hour in the first stage of labor or 1 cm of descent per hour in the second stage. Cervical examinations were done every 2 hours to document labor progression. If augmentation was necessary, oxytocin infusions were started at 6 mU/minute and increased every 15 minutes, titrating to seven contractions in 15 minutes. The maximum dose of oxytocin was 36 mU/minute. Internal uterine pressure transducers were used as clinically indicated. Electronic fetal heart rate monitoring, external or internal, was used routinely.
The control protocol consisted of admission to the labor suite based on cervical dilatation of 3–4 cm with regular, painful uterine contractions. If labor did not progress adequately, oxytocin augmentation was begun at 1 mU/minute and increased by 1 mU/minute every 30–40 minutes to achieve and maintain 200 Montevideo units of uterine activity.
Epidural analgesia was administered on patient request, at the discretion of the attending obstetrician and anesthesiologist. Parturients received continuous infusions of 0.08% bupivacaine plus fentanyl 1 µg/mL, or the same dose of bupivacaine with sufentanil 1 µg/mL after an initial bolus of 0.125% bupivacaine with 50 µg fentanyl or 10 µg sufentanil. A small subset of women, 6% in each arm, received only diluted bupavacaine in their epidurals. Three women in each group did not have their epidurals dosed because of difficult placement or suspected intravascular placement, and were included in their original intent-to-treat groups. Epidural infusions were titrated to a T8–T10 sensory level and were continued throughout the second stage of labor. Early epidural placement was defined as placement at a cervical dilatation up to 4 cm, and late placement as more than 4 cm.
Statistical analysis used unpaired t tests for continuous variables and 
2 analysis for frequency data. Fisher exact test was used when cell size was small. Two-way analysis of variance was used where appropriate to compare active with control groups and dilatation less than 4 cm versus greater than 4 cm. Multivariate logistic regression analysis was used for binary outcomes. Analysis of covariance methods were used for the multivariate analysis of continuous outcomes. Data are expressed as mean ± standard deviation (SD). Significance was P < .05.
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Results |
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). During labor, comparable numbers of women in each group had oxytocin augmentation (early 121 [68%] versus late 46 [61%]; P = .31), internal fetal and uterine monitoring (early 132 [75%] versus late 59 [78%]; P = .30), artificial rupture of membranes (early 147 [82%] versus late 66 [87%]; P = .46), and thick meconium-stained fluid (early 14 [8%] versus late six [8%]; P = .88).
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). Among women who had vaginal deliveries, active management of labor was associated with shorter labors than in controls, regardless of epidural timing (Table 2). When stratified by early versus late placement of epidurals and management of labor, early epidural placement was associated with decreased length of labor compared with late placement in the control group only (Table 2). Second stages of labor were not lengthened in women who had early versus late placement of epidurals or when stratified by labor management, although numbers in these subgroups were small (Table 2). In a multivariate analysis, the difference in the total length of labor between the groups with early and late placement of epidurals was maintained when controlling for cofactors, including randomization, modes of delivery, use of oxytocin, patients’ ages, estimated gestational ages, and newborn weights.
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There were no adverse neonatal or maternal outcomes in this cohort of healthy nulliparas. One infant in each group had a 5-minute Apgar score less than 7, and 13 infants in the early and four in the late group were admitted to the neonatal intensive care unit for a transition period. Two early-epidural infants had arterial blood gases less than 7.0 pH and were transferred to the regular nursery with otherwise normal postpartum courses. Neither estimated blood loss (early 461 ± 285 versus late 405 ± 205 mL; P = .12) nor episiotomy rates (early 66 [43%] versus late 26 [37%]; P = .46) varied between the groups.
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Discussion |
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In the present study, only women who had epidurals were analyzed. Parturients who request epidurals may be different from those who do not, with longer, more painful, and dysfunctional labors. Thus, comparing women who request epidurals with those who do not might introduce a selection bias. For example, in our original randomized cohort of 405, the cesarean rate among women who did not request epidurals was 2.7%, whereas the overall abdominal-delivery rate among women with epidurals was much higher, at 12.5%.9 In this study, we analyzed the timing of epidural placement and the method of labor management to evaluate their effects on labor and mode of delivery. We found that active management of labor shortened labor regardless of when epidurals were given and that our cohort with early epidural placement had shorter labors than women with later placement.
The benefit of early epidural placement is a reduction in the length of time that parturients experience labor pain. We found that early epidural placement was not associated with longer labor; in fact, women with early epidurals had shorter labors than those with late placement. There were no increases in the length of the second stage of labor in women with early placement or any increase in rates of operative vaginal deliveries, although these subgroups were small.
We also showed significant reductions in lengths of labor in actively managed women who received epidurals as compared with standard protocol management, which chiefly occurred in the first stage. This reduction of labor length held true regardless of when the epidural was placed. The benefit of active management may be its ability to shorten labor despite epidural analgesia. This issue was addressed in two retrospective abstract reports from Dublin comparing experiences in the years 1973 and 1992 and in the years 1987 and 1992. ( Boylan P, Robson M, McParland P. Active management of labor, 1973–1992. Am J Obstet Gynecol 1993;168:295; and Robson M, Boylan P, McParland P. Epidural analgesia need not influence the spontaneous vaginal delivery rate. Am J Obstet Gynecol 1993;168: 364). These reports concluded that active management was able to overcome the effect of epidural analgesia on labor. However, cesarean rates doubled from 5% to 10% over the course of the study in one of the reports. Active management of labor consistently showed reductions in lengths of labor, but the effects on cesarean rates were not consistent.7–9 In the present study, we did not observe significant reductions in cesarean rates, although we did see a trend toward lower cesarean rates among actively managed women with epidurals. One thousand four hundred fifty women would be required to show with 80% power a reduction in cesarean rates from 15% in controls with epidurals to 11% in actively managed women with epidurals, which would take approximately 28 years to accrue. A multicenter collaborative study is needed to answer this question definitively. Although no statistically significant differences were seen in cesarean rates in women who had early versus late epidurals, the observed difference (early 15% versus late 8%; P = .21) might be clinically significant. To accrue the number of patients required to show that no difference exists would take approximately 14 years at our current delivery rates.
The opinion that epidurals given early in labor are deleterious to normal labor progress and successful vaginal deliveries2 was not confirmed in our study. However, our patients with later epidurals showed a trend toward decreased cesarean rates, which was not statistically significant. The reason might be that the number of women who had cesareans in the late cohort was too small to achieve the needed statistical power. Our cutoff of 4 cm dilatation also might have been too advanced to show a difference between early and late epidurals, a problem with other studies.11,12 Because epidural analgesia is a safe, highly effective pain reliever in labor, it is appropriate to find ways to optimize labor progress and outcome in women who choose it as part of their delivery experience.
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Footnotes |
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Received May 28, 1998. Received in revised form December 2, 1998. Accepted December 17, 1998.
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References |
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2. Thorp JA, Hu DH, Albin RM, McNitt J, Meyer BA, Cohen GR, et al. The effect of intrapartum epidural analgesia on nulliparous labor: A randomized prospective trial. Am J Obstet Gynecol 1993;169: 851–8.[Medline]
3. Ramin SM, Gambling DR, Lucas MJ, Sharma SK, Sidawi JE, Leveno KJ. Randomized trial of epidural versus intravenous analgesia during labor. Obstet Gynecol 1995;86:783–9.[Abstract]
4. Philipsen T, Jensen NH. Epidural block or parenteral pethidine as analgesic in labor: A randomized study concerning progress in labour and instrumental deliveries. Eur J Obstet Gynecol Reprod Biol 1989;30:27–33.[Medline]
5. Lieberman E, Lang JM, Cohen A, D’Agostino R Jr, Datta S, Frigoletto FD Jr. Association of epidural analgesia with cesarean delivery in nulliparas. Obstet Gynecol 1996;88:993–1000.[Abstract]
6. O’Driscoll K, Foley M, McDonald D. Active management of labor as an alternative to cesarean sections for dystocia. Obstet Gynecol 1984;63:485–90.
7. Lopez-Zeno JA, Peaceman AM, Adashek JA, Socol ML. A controlled trial of a program for the active management of labor. N Engl J Med 1992;326:450–4.[Abstract]
8. Frigoletto FD, Lieberman E, Lang JM, Choen A, Barss V, Ringer S, et al. A clinical trial of active management of labor. N Engl J Med 1995;333:745–50.
9. Rogers R, Gilson GJ, Miller AC, Izquierdo LE, Curet LB, Qualls CR. Active management of labor: Does it make a difference? Am J Obstet Gynecol 1997;177:599–605.[Medline]
10. Thorp JA, Breedlove G. Epidural analgesia in labor: An evaluation of risks and benefits. Birth 1996;23:63–83.[Medline]
11. Chestnut DH, McGrath JM, Vincent RD Jr, Penning DH, Choi WW, Bates JN, et al. Does early administration of epidural analgesia affect obstetric outcome in nulliparous women who are in spontaneous labor? Anesthesiology 1994;80:1201–8.[Medline]
12. Chestnut DH, Vincent RD Jr, McGrath JM, Choi WW, Bates JN. Does early administration of epidural analgesia affect obstetric outcome in nulliparous women who are receiving intravenous oxytocin? Anesthesiology 1994;80:1193–200.[Medline]
13. Manyonda IT, Shaw DE, Drife JO. The effect of delayed pushing in the second stage of labor with continuous lumbar epidural analgesia. Acta Obstet Gynecol Scand 1990;69:291–5.[Medline]
This article has been cited by other articles:
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  R. R Patel, T. J Peters, D. J Murphy, and the ALSPAC Study Team Prenatal risk factors for Caesarean section. Analyses of the ALSPAC cohort of 12 944 women in England Int. J. Epidemiol., April 1, 2005; 34(2): 353 - 367. [Abstract] [Full Text] [PDF]
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 H. K. Eltzschig, E. S. Lieberman, and W. R. Camann Regional Anesthesia and Analgesia for Labor and Delivery N. Engl. J. Med., January 23, 2003; 348(4): 319 - 332. [Full Text] [PDF]
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