Epidural analgesia (EA) during the active phase of labor is the most frequent treatment for pain control during labor and delivery. The effect of regional analgesia on the progress of labor and mode of delivery has often been debated. Results of randomized-controlled trials and systematic reviews published between 2002 and 2004 did not show any difference in the rate of cesarean deliveries between women who had received EA and women who had only received intravenous analgesia 1. However, various unwanted side effects were associated with its use, including longer labor; increased incidence of maternal fever (with an associated increase in the use of antibiotics for mothers and newborns); and increased rates of operative vaginal delivery and perineal trauma, such as more third-degree and fourth-degree tears 2. The aim of this study is to evaluate the effect of EA on the progress of labor when applied during the latent phase and whether or not the mode of delivery will be affected.
Materials and methods
The present study was a prospective randomized study on women attending deliveries in Kasr Al Ainy Hospital. Women were divided into two groups: group A included 50 parturient women who received EA during the latent phase of labor when the cervix was dilated 3 cm or less. Group B included 50 parturient women who received EA during the active phase of labor when the cervix was dilated 4 cm or more. We included only primigravida women ranging in age from 20 to 40 years with singleton pregnancy and cephalic presentation. Multigravidas or those with malpresentations/multiple pregnancies/medical disorders especially hematological disorders were excluded. Randomization was performed by a third party (the attending nurse). Laboratory investigations, including complete blood count and coagulation profile (PT, PC), were carried out for all cases.
Epidural analgesia procedure
All women had epidural analgesia after an intravenous preload of 500ml lactate Ringer s solution, as follow: 10ml of a solution containing bupivacaine 0.0625%, and 2mg/ml of fentanyl in epidural catheter initially, followed by top up doses according to the parturient demand. The following were recorded: (a) duration of delivery: time lapsed after the administration of the epidural and the duration of delivery; (b) mode of delivery: the mode of delivery could have been either normal vaginal delivery or cesarean section (CS) and the related reasons for the CS; and (c) fetal outcome, assessed according to the APGAR score.
Data were statistically described in terms of range, mean±SD, frequencies (number of cases), and percentages when appropriate. Comparison of quantitative variables between the study groups was performed using the Student t-test or the Mann–Whitney test where appropriate. The data obtained from both the study group and the control group were analyzed statistically using Microsoft Excel (Microsoft Corporation, New York, New York, USA) and the statistical package for social science (SPSS) statistical programs (SPSS Inc., Chicago, Illinois, USA).
There was no significant difference between both the groups in the duration of delivery, the degree of effacement, mode of delivery, or APGAR score (Table 1). However, there was a significant difference between both the groups in the degree of cervical dilation and this was expected as epidural was applied in two different phases (active and latent). The incidence of postepidural headache was not different between both the groups (20 vs. 30%, respectively, P value 0.9) (Fig. 1). The different reasons for CS are shown in Fig. 2. No instrumental delivery was recorded in both the groups.
The data from this study show that the administration of EA in the latent phase of spontaneous labor at term, compared with the active phase, did not increase the rate of intrapartum cesarean deliveries. This has been reported by other investigators who have used a lower limit of cervical dilatation of 1 cm before epidural insertion and concluded that EA in the latent phase of labor at cervical dilation of 1.0 cm or more does not prolong the progression of labor and does not increase the rate of cesarean deliveries in nulliparous women compared with the delayed analgesia at cervical dilation of 4.0 cm or more 3. However, other investigators have found that intrathecal (spinal) opioid use significantly shortened the first stage of labor compared with the administration of a systemic opioid. In that trial, a slightly longer but not statistically significant prolonged duration of the first stage of labor was found in women who received epidurals in the latent phase 4.
Marucci et al. 5 performed a systematic review and found no increased risk of cesarean delivery or instrumental vaginal delivery for women receiving early EA compared with late EA. Therefore, a woman’s request for EA early in labor cannot be rejected on the grounds of its presumed adverse effects. Also, individual results of all randomized-controlled trials showed no increased risk for cesarean delivery or instrumental vaginal delivery in the early EA group. These results suggest that it is unlikely that specific analgesia techniques are associated with an increased risk of cesarean or instrumental vaginal delivery. Only one retrospective cohort study showed an increased risk of instrumental vaginal delivery 6.
The incidence of the different reasons for CS in both the groups of patients was recorded. The main reasons were fetal distress, failure to progress, and obstruction. The incidence was 42.9 and 30% in cases of fetal distress, 42.9 and 70% in cases of failure to progress, and 14.3 and 0% in obstruction in both active and latent phases, respectively. This was also supported by the 2000 Cochrane meta-analysis, which compared EA with narcotics, and did not show increased rates of CS associated with EA. For many practitioners, this was surprising; in practice, EA certainly seemed to lead to an increase in the rates of CS, especially when used before the active phase of labor. In contrast to the conclusion of the Cochrane meta-analysis of EA compared with narcotic analgesia, EA administered before the active phase of labor more than doubles the probability of receiving a CS. If administered in the active phase of labor, EA does not lead to an increase in the rates of CS 7.
In the present study, we defined early epidural or the upper limit of cervical dilatation in the latent phase was less than 3 cm; however, Marucci and colleagues defined early EA as a cervical dilatation less than 4–5 cm, whereas we used the stricter lower limit of less than 4 cm. These women suffer from severe pain in the latent first stage of labor, whose request for regional analgesia should not be denied. However, Ohel et al.8 administered EA in the latent phase of the first stage of labor at a cervical dilation of at least 1.0 cm versus the active phase analgesia at 4.0 cm or more (unlike the measurements we used); they found a statistical difference in the CS rate, which was not found in our results.
In the present study, instrumental delivery was not performed in both the groups. This is also supported by data from other investigators who found that there is no increased risk of instrumental delivery in nulliparous women who receive EA early in (term) labor. Torvaldsen and colleagues found that there was little difference between combined spinal epidural and EA in labor despite a slightly faster onset of pain relief with combined spinal epidural and fewer complaints of pruritus with EA. No difference was observed in obstetric or neonatal outcome 9. In conclusion, EA in the latent phase of labor does not seem to differ from its application in the active phase in terms of progress of labor or the fetal outcome.
Conflicts of interest
There are no conflicts of interest.
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