***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: OBJECTIVE To evaluate the effect of second-stage epidural bupivacaine on the outcome of labor . METHODS Two groups of 35 patients each were r and omly allocated to receive continuous epidural bupivacaine throughout labor ( group 1 ) or until an 8-cm dilatation of the cervix ( group 2 ) . RESULTS There was no significant difference between the 2 groups in the rates of instrument deliveries and in their Apgar scores . CONCLUSIONS The administration of continuous epidural bupivacaine ( 0.25 % ) throughout labor and delivery does not seem to affect the outcome of labor To compare the use of  r and omized controls ( RCTs ) and historical controls ( HCTs )  for clinical trials , we search ed the literature for therapies studied by both methods . We found six therapies for which 50 RCTs and 56 HCTs were reported . Forty-four of 56 HCTs  ( 79 percent ) found the therapy better than the control regimen , but only 10 of 50 RCTs ( 20 percent ) agreed . For each therapy , the treated patients in RCTs and HCTs of the same therapy was largely due to differences in outcome for the control groups , with HCT control patients generally doing worse than the RCT control groups . Adjustment of the outcomes of the HCTs for prognostic factors , when possible , did not appreciably change the results . The data suggest that biases in patient selection may irretrievably weight the outcome of HCts in favor of new therapies . RCTs may miss clinical ly important benefits because of inadequate attention to sample size . The predictive value of each might be improved by reconsidering the use of p less than 0.05 as the significance level for all types of clinical trials , and by the use of confidence intervals around estimates of treatment effects BACKGROUND In laboratory animals , cerebral ischaemia is worsened by hyperthermia and improved by hypothermia . Whether these observations apply to human beings with stroke is unknown . We therefore examined the relation between body temperature on admission with acute stroke and various indices of stroke severity and outcome . METHODS In a prospect i ve and consecutive study 390 stroke patients were admitted to hospital within 6 h after stroke ( median 2.4 h ) . We determined body temperature on admission , initial stroke severity , infa rct size , mortality , and outcome in survivors . Stroke severity was measured on admission , weekly , and at discharge on the Sc and inavian Stroke Scale ( SSS ) . Infa rct size was determined by computed tomography . Multiple logistic and linear regression outcome analyses included relevant confounders and potential predictors such as age , gender , stroke severity on admission , body temperature , infections , leucocytosis , diabetes , hypertension , atrial fibrillation , ischaemic heart disease , smoking previous stroke , and comorbidity . FINDINGS Mortality was lower and outcome better in patients with mild hypothermia on admission ; both were worse in patients with hyperthermia . Body temperature was independently related to initial stroke severity ( p < 0.009 ) , infa rct size ( p < 0.0001 ) , mortality ( p < 0.02 ) , and outcome in survivors ( SSS at discharge ) ( p < 0.003 ) . For each 1 degrees C increase in body temperature the relative risk of poor outcome ( death or SSS score on discharge < 30 points ) rose by 2.2 ( 95 % CI 1.4 - 3.5 ) ( p < 0.002 ) . INTERPRETATION We have shown that , in acute human stroke , an association exists between body temperature and initial stroke severity , infa rct size , mortality , and outcome . Only intervention trials of hypothermic treatment can prove whether this relation is causal OBJECTIVE To compare two methods of epidural labor analgesia regarding the incidence of post-partum urinary retention . STUDY DESIGN One thous and parturients who requested epidural analgesia for the relief of labor pain received , at r and om , either bupivacaine 0.25 % with adrenaline 1:200 000 ( n = 500 ) or bupivacaine 0.125 % with 10 micrograms sufentanil ( n = 500 ) . During the same observation period all women with clinical ly significant urinary retention ( > 500 ml , requiring indwelling catheter ) were registered . RESULT Altogether 30/3.364 parturients had clinical ly significant urinary retention . Twenty-seven of these had received epidural analgesia ( EDA ) ( 17 with bupivacaine/adrenaline and ten with bupivacaine/sufentanil , a non-significant differences ) . The number of parturients with urinary retention was highly increased following EDA ( 27/1000 ) as compared to those not receiving EDA ( 3/2364 ) , P < 0.001 ( Fisher 's exact test ) . In patients with EDA and urinary retention there were no difference between the groups in the incidence of instrumental deliveries or vaginal/perirectal tears . All parturients regained normal bladder function . CONCLUSION EDA significantly increased the risk of post-partum urinary retention but no difference was found between the two epidural techniques CONTEXT Exposure to maternal or placental infection is related to risk of preterm birth and , in premature infants , of brain lesions predictive of cerebral palsy ( CP ) . Few studies have investigated whether maternal infection is associated with risk of CP in children of normal birth weight . OBJECTIVE To investigate maternal infection during the admission for delivery as a possible risk factor for CP in infants born weighing 2500 g or more . DESIGN Population -based case-control study . SETTING All hospitals in 4 northern California counties , 1983 through 1985 . PARTICIPANTS A total of 46 children with disabling spastic CP who had no recognized prenatal brain lesions and 378 r and omly selected control children weighing 2500 g or more at birth and surviving to age 3 years . MAIN OUTCOME MEASURES Disabling spastic CP and signs of neonatal morbidity . RESULTS Maternal fever exceeding 38 degrees C in labor was associated with increased risk of unexplained CP ( odds ratio [ OR ] , 9.3 ; 95 % confidence interval [ CI ] , 2.7 - 31.0 ) , as was a clinical diagnosis of chorioamnionitis . One or more indicators of maternal infection were present in 2.9 % of control children , 22 % of children with CP ( OR , 9.3 ; 95 % CI , 3.7 - 23.0 ) , and 37 % of those with the spastic quadriplegic subtype of CP ( OR , 19.0 ; 95 % CI , 6.5 - 56.0 ) . Newborns exposed to maternal infection , both cases and controls , had 5-minute Apgar scores below 6 more often than those unexposed . Among children with CP , those born to infected women were more often hypotensive , needed intubation , had neonatal seizures , and received a clinical diagnosis of hypoxic-ischemic encephalopathy . CONCLUSION Intrauterine exposure to maternal infection was associated with a marked increase in risk of CP in infants of normal birth weight . Maternal infection was also linked with low Apgar scores , other evidence of hypotension [ corrected ] and need for resuscitation , and neonatal seizures-signs commonly attributed to birth asphyxia OBJECTIVE To determine whether cervical dilatation at the time of placement of patient-requested epidural affects cesarean rates or lengths of labors in actively managed parturients . METHODS The charts of 255 women r and omized to active management of labor ( n = 125 ) or control protocol s ( n = 130 ) were review ed 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 Objective To use intrapartum sonography as a tool to investigate the development of the persistent occiput posterior position during labor , as well as to identify parameters correlating with the outcome of labor . Methods A prospect i ve study of 408 women in labor after 37 weeks ' gestation with a singleton fetus in a vertex position using sonography at the onset of labor was performed . Fetal position , placental location , and maternal BMI ( body mass index ) were recorded . Outcome of labor was monitored for all relevant parameters . Results Most ( 68 % ) of persistent occiput posterior positions develop through a malrotation during labor from an initially occipitoanterior position . Only 32 % of persistent cases were occipitoposterior ( dorsoposterior ) at the onset of labor ; operative interventions were required in 87.5 % of these . Of the 61 ( 15 % ) occipitoposterior positions at the onset of labor , 53 ( 87 % ) rotated into an occiput anterior position . Persistent occiput posterior position was more common in the initially occipitoposterior group ( P < 0.01 , Fisher exact test ) , and posterior placental locations were fewer ( z test , P = 0.05 ) . Also , operative deliveries were more common in the group remaining occipitoposterior throughout labor ( P < .01 , Fisher exact test ) . A higher maternal BMI correlated with neonatal weight ( P < .01 , Pearson correlation ) , an increase in operative deliveries ( P = .032 , Pearson correlation ) , lower Apgar scores at 1 minute ( P = .02 , Spearman correlation ) , and increase in posterior placental locations ( P = .037 , two-tailed t test ) . Conclusion In most cases , persistent occiput posterior position develops through a malrotation and only in a little more than one-third of cases through absence of rotation from an initially occipitoposterior position . Higher maternal BMI correlates with higher fetal weight , increased operative deliveries , lower Apgar scores at 1 minute , and posterior placental locations .  Intrapartum sonography proved to be useful in investigating the development of the persistent occipitoposterior position A r and omized , double-blind , placebo-controlled study was performed to evaluate the analgesic efficacy and influence of continuing an epidural infusion of 0.0625 % bupivacaine-0.0002 % fentanyl during the second stage of labor in nulliparous women . When the cervix was fully dilated , coded study solution was substituted for the known bupivacaine-fentanyl solution . The study solution for 29 patients was 0.0625 % bupivacaine-0.0002 % fentanyl ; 34 patients received saline placebo . The two groups had similar pain scores during the first stage of labor . During the second stage , pain scores were significantly higher in the saline-placebo group at each 30-min interval between 60 and 150 min after the diagnosis of full cervical dilation . Similarly , there was a significant difference between the two groups in global assessment of analgesia quality during the second stage , but the difference occurred in those patients with a second-stage duration of greater than or equal to 60 min . Among the women who delivered vaginally , eleven of 28 ( 39 % ) women in the bupivacaine-fentanyl group , versus five of 34 ( 15 % ) in the saline-placebo group , had surgical perineal anesthesia for vaginal delivery ( P less than .05 ) . Six of 28 ( 21 % ) women in the bupivacaine-fentanyl group , and five of 34 ( 15 % ) in the saline-placebo group , underwent instrumental vaginal delivery ( P = NS ) . The median duration of the second stage of labor was 53 min ( range = 5 - 283 ) in the bupivacaine-fentanyl group , and 63 min ( range = 16 - 181 ) in the saline-placebo group ( P = NS ) . ( ABSTRACT TRUNCATED AT 250 WORDS Abstract Objectives : To assess in a prospect i ve r and omised study the association between motor block result ing from high and low dose epidural infusions of bupivacaine in labour and the incidence of long term backache after childbirth , and to compare the incidence of backache in women not receiving epidural analgesia . Design : Women requesting epidural analgesia in labour between October 1991 and March 1994 were r and omised to receive infusions of either bupivacaine alone or low dose bupivacaine with opioid . Data were collected during labour 
    Output:
    
Despite this variation , there is sufficient evidence to conclude that epidural is associated with a lower rate of spontaneous vaginal delivery , a higher rate of instrumental vaginal delivery and longer labors , particularly in nulliparous women .
Women receiving epidural are also more likely to have intrapartum fever and their infants are more likely to be evaluated and treated for suspected sepsis .
There is insufficient evidence to determine whether epidural does or does not tend to increase the risk of cesarean delivery or fetal malposition .
Adverse effects on the fetus may occur in the subset of women who are febrile .