***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background The minimum local analgesic concentration ( MLAC ) has been defined as the median effective local analgesic concentration ( EC50 ) in a 20-ml volume for epidural analgesia in the first stage of labor . The aim of this study was to determine the relative local anesthetic sparing efficacies of intravenous and epidural fentanyl by comparison of their effects on the MLAC of bupivacaine . Methods In this double-blind , r and omized , prospect i ve study , 84 parturients at ≤ 7-cm cervical dilation who requested epidural analgesia were allocated to one of two groups . After lumbar epidural catheter placement , 20 ml bupivacaine ( n = 44 ) or bupivacaine with 3 & mgr;g/ml ( 60 & mgr;g ) fentanyl ( n = 40 ) was administered . The plain bupivacaine group then received 60 & mgr;g intravenous fentanyl . The bupivacaine – fentanyl group received intravenous saline . The concentration of bupivacaine was determined by the response of the previous patient in that group to a higher or lower concentration using up – down sequential allocation . Analgesic efficacy was assessed using 100-mm visual analog pain scores , with ≤ 10 mm within 30 min defined as effective . Results The MLAC  of bupivacaine – intravenous fentanyl was 0.064 % wt/vol ( 95 % confidence interval , 0.049–0.080 ) , and the MLAC of bupivacaine – epidural fentanyl was 0.034 % wt/vol ( 95 % confidence interval , 0.017–0.050 ) . Epidural fentanyl significantly increased the analgesic potency of bupivacaine  by a factor of 1.88 ( 95 % confidence interval , 1.09–3.67 ) compared with intravenous fentanyl . The epidural fentanyl group demonstrated significantly higher dermatomal spread ( P = 0.0064 ) and increased pruritus ( P = 0.01 ) . Conclusions Epidural fentanyl significantly reduced the MLAC of bupivacaine when compared with intravenous fentanyl for the parturients in this study . The significantly enhanced local anesthetic sparing , dermatomal level , and pruritus with epidural fentanyl suggest a primarily spinal site of action OBJECTIVE To evaluate the effects of epidural analgesia using 0.2 % Ropivacaine on the mother , newborn and during labor . METHODS This study was conducted at the Zeynep Kamil Obstetric , Gynecology , and Pediatric Research and Training Hospital in Istanbul , Turkey , between July 2003 and April 2004 . Eighty pregnant women of 37 - 41 weeks ' gestation were enrolled in the study . Forty cases received epidural analgesia ( group 1 ) and the control group composed 40 cases ( group 2 ) . Duration of labor , systolic and diastolic blood pressures at initial , 15th , 30th , 45th and 60th minutes , and number of breathing per minute , pulse rates , fetal heart rates and presence of motor block were recorded . Blood gas assessment s from the umbilical cord , 1st and 5th minute Apgar scores were noted following the delivery . Way of delivery , adverse effects and complications of the epidural analgesia were recorded . RESULTS Mean age of the cases was 24.79 + /- 4.72 years .  Duration between full cervical dilation and delivery ( phase 2 ) was significantly longer in group 1 ( p<0.01 ) . Sixty minutes systolic arterial pressure was significantly lower in group 1 ( p<0.05 ) . In group 1 , diastolic arterial pressures at 15th , 45th , 60th minutes ( p<0.01 ) and 30th minute ( p<0.05 ) were significantly lower when compared to the initial values . No significant differences were recorded in terms of breathing rates , umbilical cord CO2 , O2 , pH levels and Apgar scores between the 2 groups . The most common adverse effect of epidural analgesia was sedation ( 59 % ) . The second dose of Ropivacaine was needed in 24 ( 61.5 % ) cases in group 1 . In group 1 , 29 ( 74.4 % ) patients expressed their pleasure as very good regarding the epidural analgesia . CONCLUSION Epidural analgesia , if administered by a specialist to a properly selected patient at proper time , leads to a comfortable delivery by relieving the pain . It can be performed safely after taking an informed consent Purpose Epidural analgesia is associated with hyperthermia  during labor and presumably causes it , although no convincing mechanism has been postulated . It seems likely that fever associated with pyrogenic factors related to labor is suppressed by opioids , whereas it is expressed normally in patients given epidural analgesia . We examined this hypothesis and the possible etiology of temperature elevation in labor . Methods In this prospect i ve , r and omized , controlled study , we assessed 201 parturients during spontaneous labor . Analgesia was r and omly provided with one of four treatment groups : ( 1 ) epidural ropivacaine alone , ( 2 ) IV remifentanil alone , ( 3 ) epidural ropivacaine plus IV remifentanil , and ( 4 ) epidural ropivacaine plus IV acetaminophen . At r and omization , patients were normothermic . Intrapartum hyperthermia ( ≥38 ° C ) was correlated to the analgesic technique . Results The maximum increase in oral temperature was greatest in the ropivacaine group ( 0.7 ± 0.6 ° C ) and least in the remifentanil group ( 0.3 ± 0.4 ° C ; P = 0.013 ) . The percentage of patients who became hyperthermic ( ≥38 ° C ) during the first 6 h of labor was greatest in the ropivacaine group ( 14 % ) and least in the remifentanil-alone group ( 2 % ) , but the difference was not statistically significant . The maximum forearm-finger gradients were lower ( less vasoconstriction ) in the remifentanil group when compared to the gradients in patients with epidural analgesia ( 1.4 ± 1.8 vs 3.0 ± 1.7 , respectively ; P < 0.001 ) . Conclusion Our results are consistent with the theory that low-dose opioids inhibit fever in patients not given epidural analgesia . However , in view of the negative results , the hypothesis of epidural-induced hyperthermia may be question able Background Reports indicate that the administration of epidural analgesia for pain relief during labor interferes with labor and increases cesarean deliveries . However , only a few controlled trials have assessed the effect of epidural analgesia on the incidence of cesarean delivery . The authors ' primary purpose in this r and omized study was to evaluate the effects of epidural analgesia on the rate of cesarean deliveries by providing a suitable alternative : patient-controlled intravenous analgesia . Methods Seven hundred fifteen women of mixed parity in spontaneous labor at full term were r and omly assigned to receive either epidural analgesia or patient-controlled intravenous meperidine analgesia . Epidural analgesia was maintained with a continuous epidural infusion of 0.125 % bupivacaine with 2 micro gram/ml fentanyl . Patient-controlled analgesia was maintained with 10 - 15 mg meperidine given every 10 min as needed using a patient-controlled pump . Procedures recorded in a manual that prescribed the intrapartum management were followed for each woman r and omized in the study . Results A total of 358 women were r and omized to receive epidural analgesia , and 243 ( 68 % ) of these women complied with the epidural analgesia protocol . Similarly , 357 women were r and omized to receive patient-controlled intravenous meperidine analgesia , and 259 ( 73 % ) of these women complied with the patient-controlled intravenous analgesia protocol . Only five women who were r and omized and received patient-controlled intravenous meperidine analgesia according to the protocol crossed over to epidural analgesia due to inadequate pain relief . There was no difference in the rate of cesarean deliveries between the two analgesia groups using intention-to-treat analysis based on the original r and omization ( epidural analgesia , 4 % [ 95 % CI : 1.9 - 6.2 % ] compared with patient-controlled intravenous analgesia , 5 % [ 95 % CI : 2.6 - 7.2 % ] ) . Similar results were observed for the analysis of the protocol -compliant groups ( epidural analgesia , 5 % [ 95 % CI : 2.6 - 8.5 % ] compared with patient-controlled intravenous analgesia , 6 % [ 95 % CI : 3 - 8.9 % ] ) . Women who received epidural analgesia reported lower pain scores during labor and delivery compared with women who received patient-controlled intravenous analgesia . Conclusions Epidural analgesia was not associated with increased numbers of cesarean delivery when compared with a suitable alternative method of analgesia OBJECTIVE To estimate the effect of epidural analgesia on the Friedman labor curve . METHODS This study was a secondary analysis of a previously reported r and omized trial of the effects of patient‐controlled epidural analgesia during labor compared with patient‐controlled meperidine on cesarean delivery rate . All subjects had a singleton , cephalic , nonanomalous fetus at or beyond 37 weeks ' gestation . This secondary analysis was limited to women who had cervical dilatation commencing of at least 3 cm ( ie , active phase of labor ) . RESULTS A total of 459 women were r and omized . Twenty‐five women were excluded for a cervix less than 3 cm dilated , leaving 220 women allocated to patient‐controlled epidural analgesia and 214 to patient‐controlled intravenous meperidine available for analysis . There were no significant demographic differences between the two groups , including age , race , gestational age , and cervix on admission . The active phase of labor was 1 hour longer in the epidural‐treated group ( 6.0 ± 3.2 hours versus 5.0 ± 3.2 hours , P < .001 ) . The rate of cervical dilation was significantly less with epidural analgesia ( 1.4 cm/h versus 1.6 cm/h , P < .002 ) . The duration of the second stage tended to be longer in the epidural group ( 1.1 ± 1.5 hours versus 0.9 ± 1.0 hours , P = .079 ) . CONCLUSION Epidural analgesia prolonged the active phase of labor by 1 hour compared with Friedman 's original criteria Background Whether epidural analgesia for labor prolongs the active-first and second labor stages and increases the risk of vacuum-assisted delivery is a controversial topic . Our study was conducted to answer the question : does lumbar epidural analgesia with lidocaine affect the progress of labor in our obstetric population ? Method 395 healthy , nulliparous women , at term , presented in spontaneous labor with a singleton vertex presentation . These patients were r and omized to receive analgesia either , epidural with bolus doses of 1 % lidocaine or intravenous , with meperidine 25 to 50 mg when their cervix was dilated to 4 centimeters . The duration of the active-first and second stages of labor and the neonatal apgar scores were recorded , in each patient . The total number of vacuum-assisted and cesarean deliveries were also measured . Results 197 women were r and omized to the epidural group . 198 women were r and omized to the single-dose intravenous meperidine group . There was no statistical difference in rates of vacuum-assisted delivery rate . Cesarean deliveries , as a consequence of fetal bradycardia or dystocia , did not differ significantly between the groups . Differences in the duration of the active-first and the second stages of labor were not statistically significant . The number of newborns with 1-min and 5-min Apgar scores less than 7 , did not differ significantly between both analgesia groups . Conclusion Epidural analgesia with 1 % lidocaine does not prolong the active-first and second stages of labor and does not increase vacuum-assisted or cesarean delivery rate BACKGROUND Epidural analgesia initiated early in labor ( when the cervix is less than 4.0 cm dilated ) has been associated with an increased risk of cesarean delivery . It is unclear , however , whether this increase in risk is due to the analgesia or is attributable to other factors . METHODS We conducted a r and omized trial of 750 nulliparous women at term who were in spontaneous labor or had spontaneous rupture of the membranes and who had a cervical dilatation of less than 4.0 cm . Women were r and omly assigned to receive intrathecal fentanyl or systemic hydromorphone at the first request for analgesia . Epidural analgesia was initiated in the intrathecal group at the second request for analgesia and in the systemic group at a cervical dilatation of 4.0 cm or greater or at the third request for analgesia . The primary outcome was the rate of cesarean delivery . RESULTS The rate of cesarean delivery was not significantly different between the groups ( 17.8 percent after intrathecal analgesia vs. 
    Output:
    
No studies reported on rare but potentially serious adverse effects of epidural analgesia .
Epidural analgesia appears to be effective in reducing pain during labour .
However , women who use this form of pain relief are at increased risk of having an instrumental delivery .
Epidural analgesia had no statistically significant impact on the risk of caesarean section , maternal satisfaction with pain relief and long-term backache and did not appear to have an immediate effect on neonatal status as determined by Apgar scores .