The effect of epidural anesthesia on the length of labor.
Methods. A retrospective chart review of 224 women who gave birth from July 1, 1993, to June 30, 1994, was completed in a small-town family practice. The time frame included 6 months before and after the initiation of Tenncare, a state-funded health insurance plan designed to serve the uninsured and those previously served by Medicaid in Tennessee.
Results. The rate of epidural anesthesia use in this study population fell sharply after January 1, 1994, the start date for Tenncare. Epidural anesthesia by women in this study was found to increase the average length of the second stage of labor by 38 minutes for primiparas and 23 minutes for multiparas.
Conclusions. The average length of the second stage of labor is significantly longer for women who receive epidural anesthesia. The rate of epidural anesthesia use in this study population was strongly influenced by a change in health-care financing.
Key words. Anesthesia, labor stage, second; insurance, health, reimbursement. (J Fam Pract 1995; 40:244-247)
Epidural anesthesia is a common choice of analgesia during both the first and second stages of labor. Although considered safe, it affects the course, speed, and consequences of labor. Several European and Canadian studies have shown that the use of epidural anesthesia can lengthen the second stage of labor.[1-6] In one study of nulliparous women, the average length of the second stage of labor was more than 1 hour longer among women receiving epidural, compared with those who received narcotic, analgesia. Criticisms of these studies have suggested, however, that the epidural analgesia rate is confounded by the particular physician's or hospital's standard of care or the patient's inherent need for epidural anesthesia. These evaluations have suggested that women who have cephalopelvic disproportion, and thus long labors, are the ones most likely to need epidural anesthesia and subsequently to require forceps delivery or cesarean section.[8,9] These studies have been criticized for the lack of comparability among the populations studied and, therefore, the inability to isolate epidural anesthesia use as the cause of observed differences in labor.[7,10,11]
The introduction on January 1, 1994, of Tenncare, a state-funded health care insurance plan designed to serve uninsured and Medicaid patients in Tennessee, caused an immediate and significant decrease in the epidural anesthesia rate among the population of this study. Ninety-five percent of all these patients were immediately covered by Tenncare insurance. A patient's type of insurance coverage (Tenncare, Virginia Medicaid, or private) had a significant impact on whether she received epidural anesthesia during labor. There were no other changes in physician care, nursing staff, hospital, physicians involved, or demographics of the population. The purpose of this study was to examine the effect of epidural anesthesia on the length of labor.
The labor and delivery records of all patients who gave birth from July 1, 1993, to June 30, 1994, and who were in the care of the residents and faculty of the Bristol Family Practice Residency were examined retrospectively. Demographic and labor and delivery data were recorded, including date of delivery, maternal age, parity, gestational age, race, insurance, type of anesthesia, type of delivery, birthweight, and length of the second stage of labor.
In January 1994, the State of Tennessee initiated a new health insurance system called Tenncare. After January 1, 1994, most Tenncare patients did not routinely receive epidural anesthesia for childbirth.
Of 224 women who gave birth during the year of this study, 38 had cesarean sections for reasons such as previous section, maternal genital herpes, primigravida breech, cephalopelvic disproportion, and fetal distress; these women were excluded from the study. Six precipitate deliveries were also excluded because the length of the second stage of labor could not be determined. After these exclusions, 180 women were eligible for the study. There were no maternal or fetal intrapartum deaths.
Statistical significance was determined by chi-square analysis and t test.
Of the 224 women who gave birth during the year of the study, 98% were white and 2% were African American; 20% were under the age of 20 years, 66% were aged 20 to 29, and 14% were older than 29 years.
There were expected differences in age by parity: 35% of the primiparous women were under 20 years of age, 57% were aged 20 to 29, and 8% were over the age of 30 years. Only 8% of the multiparous women were younger than 20 years; 72% were aged 20 to 29, and 20% were over the age of 30 years.
In the first half of the study year, 67% of the women were insured by Tennessee Medicaid, 26% by Virginia Medicaid, 3% by private insurance, and 4% had no insurance. In the second half of the study year, 53% were covered by Tennessee Tenncare, 32% by Virginia Medicaid, 10% by private insurance, and 5% had no insurance.
Thirty-eight women gave birth by cesarean section, and 186 women had vaginal deliveries. Six of the vaginal births were excluded from the calculation because they were precipitate deliveries for which the second stage of labor could not be determined. The remaining 180 women were equally divided between primiparous and multiparous. During the first half of the study year, 96 women gave birth vaginally and 20 had cesarean sections; in the second half of the study year, 84 had vaginal births and 19 had cesarean sections. Percentages of primiparous and multiparous women were similar in both halves of the year.
The rate of epidural anesthesia fell sharply from the first half of the second half of the study year: from 80% to 33% for primiparous women, from 63% to 20% for multiparous women; and from 71% to 27% for the total group of women. In the second half of the year, multiparous and primiparous women were both significantly less likely to receive epidural anesthesia during labor (Table).
[TABULAR DATA OMITTED]
The length of second-stage labor was significantly related to epidural anesthesia use. For primiparas, the average length of the second stage was 84 minutes with an epidural and 46 minutes without it, a difference of 38 minutes. For multiparas, the average length of the second stage was 40 minutes with an epidural and 17 minutes without it, a difference of 23 minutes (Table).
There were relatively few large-for-gestational-age (LGA) babies (over 4000 g). Seven (8%) LGA babies were born to primigravidas and six (7.5%) LGA babies were born to multiparous mothers. There were eight LGA babies born to mothers who had had epidural anesthesia (five to primigravidas, three to multigravidas) and five to mothers who did not have epidural anesthesia (two to primigravidas, three to multigravidas). There were no significant differences in epidural anesthesia rates among the mothers of children born weighing over 4000 g as compared with those weighing between 3000 and 4000 g.
There was a slight decrease in the number of cesarean sections during the second 6 months of the study (24% to 18%). There were 14 forceps vaginal deliveries in the first 6 months and one in the second 6 months. Decreased use of epidural anesthesia may have been one factor in the decreased incidence of cesarean section and forceps deliveries. However, the small number of cesarean section deliveries and operative vaginal deliveries precluded analysis.
The second stage of labor is influenced by use of epidural anesthesia, the size of the baby, the mother's parity, and the vertex's station at the end of the first stage of labor. Epidural anesthesia is a common choice for anesthesia during labor. Although European studies have investigated the changes epidural anesthesia cause during labor, discussion of these effects in the United States often draw skepticism, if not outright disbelief[10,11] One European study of nulliparous women found that those receiving epidural anesthesia had a "significant prolongation" of first- and second-stage labor and an increased rate of cesarean section. This lengthening of labor was suggested as the cause of the increase in cesarean sections among women who used epidural anesthesia. A study in the United States showed that women receiving epidural anesthesia had a significantly longer mean duration of the second stage of labor. A recent meta-analysis of 230 studies strongly supports the suggestion that epidural analgesia is linked to an increase in cesarean section rates of at least 10 percentage points.
Why is this important? First, there are the obvious concerns about comfort and acceptance and tolerance of a shorter course of labor. Second, epidural anesthesia and long labors may be deleterious to the mother and possibly to the infant. One study of over 25,000 women in England showed that prolonged second stages of labor were associated with an increased incidence of postpartum hemorrhage and infection, possibly caused by an increased risk of operative deliveries. Other studies have demonstrated that women who use epidural anesthesia during labor have a higher rate of operative deliveries, malposition, cesarean section for dystocia or cephalopelvic disproportion, and a need for pitocin augmentation.[14,15] Operative vaginal deliveries and cesarean sections increase maternal morbidity, especially the incidence of postpartum hemorrhage, mortality, cost, days in hospital, days off work, and total days of discomfort.
This study was not designed to show that prolongation of labor harms the mother or child or causes an increase in the operative delivery rate; nor does it address the acceptability of operative deliveries, or the acceptability of long, often less painful labors as compared with shorter, sometimes more painful labors. Previous larger studies, however, have linked epidural anesthesia use with longer labors, increased use of operative deliveries, and possibly increased inconvenience and pain.
Some studies have shown that a prolonged second stage has no deleterious effects on the infant,[1,11] whereas others state that a prolonged second stage of labor is associated with increased perinatal morbidity. Epidural analgesia alone was associated independently with increased perinatal morbidity in one study.
Criticism of existing studies centers on the lack of comparability between patient populations who do receive epidural anesthesia and those who do not, or between the providers of care for these two groups.[10,11] For example, in some studies, the rate of epidural anesthesia use may have been influenced by the opinions of the hospital, medical staff, or nurses. Another criticism is that women who have cephalopelvic disproportion or abnormal labor patterns have longer labors and and more likely to need epidural anesthesia, operative vaginal deliveries, and cesarean sections; ie, epidural anesthesia and subsequent cesarean sections may be the result rather than the cause of abnormal or long labor patterns or cephalopelvic disproportion. Women who labor longer may be more likely to need epidural anesthesia.
In this population, however, at the time of this study, the only change from the first half of the year to the second was a change in health care reimbursement patterns. Overnight, the rate of epidural anesthesia use declined significantly for all women without any change in the population characteristics of women, hospital or hospital policy, nursing staff, nursing staff education, medical staff, physicians, anesthesiologists, or percentage of primiparous women. The demographic characteristics of the population of women who received and did not receive epidural anesthesia were the same. The number of LGA infants and infants between 3000 and 4000 g were similar for the populations of women who did and who did not use epidural anesthesia. Since there were no significant birthweight differences, these could not account for the decrease in the use of epidural anesthesia or for the shortening of the second stage of labor.
In this study, epidural anesthesia increased the mean length of the second stage of labor by 38 minutes for primiparas and 23 minutes for multiparas. A much larger study is needed to determine whether the findings related to length of labor have any effect on maternal and fetal well-being.
[1.] Saunders NS, Paterson CM, Wadsworth J. Management of labor, delivery and the puerperium: neonatal and maternal morbidity in relation to the length of second stage of labor. Obstet Gynecol Surv 1993;48:20-2. [2.] Thorp JA, Hu DH, Albin RM et al. The effect of intrapartum epidural analgesia on nulliparous labor. Am J Obstet Gynecol 1993; 169:851-8. [3.] Piper JM, Bolling DR, Newton ER. The second stage of labor: factors influencing duration. Am J Obstet Gynecol 1991;165:976-9. [4.] Kilpatrick SJ, Laros RK Characteristics of normal labor. Obstet Gynecol 1989;74:85-7. [5.] Reynolds JL, Yudkin RL. Changes in the management of labor. Length and management of the second stage. Can Med Assoc J 1987;136:1041-5. [6.] Chestnut DH, Vandewalker GE, Owen CL, Bates JN, Choi WW. The influence of continuous epidural bupivacaine analgesia on the second stage of labor and method of delivery in nulliparous women. Anesthesiology 1987;66:774-80. [7.] Chestnut DH, Thorp JA, Farisi VM. Epidural analgesia and cesarean section for dystocia. Am J Obstet Gynecol 1990;163:247-9. [8.] Chestnut DH, Laszewski LJ, Pollack KL, et al. Continuous epidural infusion of 0.0625% bupivacaine-0.0002% fentanyl during the second stage of labor. Anesthesiology 1990;72:613-8. [9.] Vertommen JD, Vandermeulen E. The effects of the addition of sufentanil to 0.125% bupivacaine on the quality of analgesia during labor and on the incidence of instrumental deliveries. Anesthesiology 1991;74:809-14. [10.] Chestnut DH. Epidural anesthesia and instrumental vaginal delivery. Anesthesiology 1991;74:805-8. [11.] Grumbach K. Epidural anesthesia [letter]. J Am Board Fam Pract 1989;2:218-9. [12.] Shyken JM, Smeltzer JS, Baxi LV, et al. A comparison of the effect of epidural, general, and no anesthesia on funic acid-base values by stage of labor and type of delivery. Am J Obstet Gynecol 1990;163: 802-7. [13.] Morton SC, Williams MS, Keeler EB, Gambone JC, Kahn KL. Effect of epidural analgesia for labor on the cesarean delivery rate. Obstet Gynecol 1994;83:1045-52. [14.] Cohen WR. Influence of the duration of second stage labor on perinatal outcome and puerperal morbidity. Obstet Gynecol 1977; 49:266-9. [15.] Niehaus LS, Chaska BW, Nesse RE. The effects of epidural anesthesia on type of labor. J Am Board Fam Pract 1988;1:238-44. Submitted, revised, December 20, 1994.
From Bristol Family Practice Residency, East Tennessee State University, Bristol. Requests for reprints should be addressed to Sigrid Johnson, MD, Bristol Family Practice Residency, East Tennessee State University, 100 Bristol College Dr, Bristol, TN 37621. [C] 1995 Appelton & Lange ISSN 0094-3509
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|Author:||Johnson, Sigrid; Rosenfeld, Jo Ann|
|Publication:||Journal of Family Practice|
|Date:||Mar 1, 1995|
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