***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 
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    Input: Fifteen patients were identified in a retrospective analysis of one institution 's experience with the use of tocolysis in selected patients with an admission diagnosis of placenta previa or abruptio placentae . There were no fetal deaths after admission , and the two neonatal deaths were related to prematurity . Eight of the 15 patients receiving tocolysis  had their pregnancies prolonged by 2 weeks or more , and there were no fetal or neonatal deaths in this group . Both neonatal deaths occurred in patients who underwent tocolysis but who gave birth within 1 day of admission . These data suggest the safety of tocolysis in preterm patients with the diagnosis of placenta previa or abruption who are bleeding . A prospect i ve , r and omized trial is required to evaluate whether tocolysis is superior to expectant management or to immediate delivery . The clinical difficulty in differentiating between these two diagnoses , despite liberal use of ultrasonography , is discussed Objective To assess the impact of maintenance nifedipine therapy on pregnancy duration in women with preterm placenta previa bleeding . Methods PPADAL was a r and omized , double-blind , placebo-controlled trial conducted between 05/2008 and 05/2012 in five French hospitals . The trial included 109 women , aged ≥ 18 years , with at least one episode of placenta previa bleeding , intact membranes and no other pregnancy complication , at gestational age 24 to 34 weeks and after 48 hours of complete acute tocolysis . Women were r and omly allocated to receive either 20 mg of slow-release nifedipine three times daily ( n = 54 ) or placebo ( n = 55 ) until 36 + 6 weeks of gestation . The primary outcome for the trial was length of pregnancy measured in days after enrolment . Main secondary outcomes were rates of recurrent bleeding , cesarean delivery due to hemorrhage , blood transfusion , maternal side effects , gestational age at delivery and adverse perinatal outcomes ( perinatal death , chronic lung disease , neonatal sepsis , intraventricular hemorrhage > grade 2 , perventricular leukomalacia > grade 1 , or necrotizing enterocolitis ) . Analysis was by intention to treat . Results Mean ( SD ) prolongation of pregnancy was not different between the nifedipine ( n = 54 ) and the placebo ( n = 55 ) group ; 42.5 days ± 23.8 versus 44.2 days ± 24.5 , p = 0.70 . Cesarean due to hemorrhage performed before 37 weeks occurred more frequently in the nifedipine group in comparison with the placebo group ( RR , 1.66 ; 95 % confidence interval , 1.05–2.72 ) . Adverse perinatal outcomes were comparable between groups ; 3.8 % for nifedipine versus 5.5 % for placebo ( relative risk , 0.52 ; 95 % confidence interval 0.10–2.61 ) . No maternal mortality or perinatal death occurred . Conclusion Maintenance oral nifedipine neither prolongs duration of pregnancy nor improves maternal or perinatal outcomes . Trial registration Clinical Trials.gov OBJECTIVES To study the effect of ritodrine therapy on maternal and perinatal outcome in cases of symptomatic placenta previa being managed conservatively . METHODS A prospect i ve , r and omized controlled clinical trial was made of a total of 60 women whose pregnancies ranged from 28 through 34 menstrual weeks who were r and omly allocated to the two study groups using Tippet 's r and om number table . Of these women , 30 were included in the study group where tocolysis with ritodrine was given whereas the other 30 in the control group did not receive tocolysis .  Prolongation of pregnancy and birth weight of the newborn were evaluated . The unpaired t-test and chi-square test were used for statistical analysis . RESULTS Use of tocolysis in symptomatic placenta previa was associated with significant prolongation of pregnancy ( 25.33 vs. 14.47 days , P<0.05 ) and difference in birth weight ( 2270 g vs. 1950 g , P<0.05 ) . There was no observed statistical difference between the two groups with regard to number of episodes of hemorrhage after admission , total amount of blood loss during stay in hospital , number of blood transfusions and maternal complications due to tocolysis in the study group . CONCLUSIONS The present prospect i ve study suggests that ritodrine hydrochloride in patients with symptomatic placenta previa tends to prolong the pregnancy and result in an increase in birth weight of the babies without causing any adverse effect on the mother and fetus OBJECTIVE Expectant management is among the current treatment options for pregnancies complicated by third-trimester bleeding at < 36 weeks ' gestation . The use of tocolytic agents to stop associated contractions is still somewhat controversial , however , and the number of cases reported to date is small . The purpose of our study was to find a large number of cases of preterm third-trimester bleeding that was treated with tocolytic agents and evaluate them for any evidence of potential harm related to the use of these agents . STUDY DESIGN Every case of third-trimester bleeding for a 6-year period was obtained from a perinatal data base that was created as patients were hospitalized . Only cases of patients with onset of bleeding between 23 and 36 weeks ' gestation were analyzed . Data collected included the gestational age at the time of first bleeding , the gestational age at delivery , whether tocolytic agents were used , the need for transfusion , maternal morbidity , and neonatal outcome . RESULTS A total of 236 cases , consisting of 131 cases of abruptio placentae and 105 cases of placenta previa , met the study criteria . In the abruptio placentae group 95 women ( 73 % ) were treated with tocolytic agents . In this group the mean gestational age at the time of first bleeding was 28.9 weeks , the mean time from bleeding until delivery was 18.9 days , the median time from bleeding until delivery was 7 days , and the neonatal mortality rate was 51 deaths/1000 live births . In the placenta previa group 76 patients ( 72 % ) were treated with tocolytic agents . In this group the mean gestational age at first bleeding was 29.5 weeks , the mean time from bleeding until delivery was 29.3 days , the median time from bleeding until delivery was 22 days , and the neonatal mortality rate was 39 deaths/1000 live births . In both groups the need for transfusion and the incidence of fetal distress were not increased by the use of tocolytic agents . Among the 171 combined patients who underwent tocolysis , no maternal morbidity related to the tocolytic agents was found and no stillbirths occurred after admission . The neonatal deaths were all related to complications of prematurity . CONCLUSIONS This is the largest series to date evaluating the use of tocolytic agents in preterm patients with third-trimester bleeding . From these data there does not appear to be any increased morbidity or mortality associated with tocolytic agent use in a controlled tertiary setting . A prospect i ve r and omized trial would be necessary to determine whether tocolytic use carries any benefits OBJECTIVE The null hypothesis is that tocolysis has no effect on pregnancy prolongation in the aggressive expectant management of symptomatic preterm placenta previa . STUDY DESIGN One hundred twelve preterm pregnancies with confirmed placenta previa and an initial episode of acute vaginal bleeding were selected for this retrospective analysis . Exclusion criteria included gestational age > or = 35 weeks , delivery within 24 hours of admission , prior treatment for bleeding or preterm labor , and contraindications to tocolytic use .  Tocolysis was prescribed , at the discretion of the treating clinical staff , in selected pregnancies with significant uterine contractions after admission of the patient . The majority of treated patients ( 85 % ) received intravenous magnesium sulfate and /or oral or subcutaneous beta-sympathomimetics within 24 hours of admission . Most patients remained hospitalized until delivery under this aggressive expectant management protocol . Both treated and untreated control study groups were similar at inclusion with regard to parity , gestational age , contraction frequency , and degree of initial bleeding . Outcome variables for each treatment group were obtained from final chart review . Continuous and categoric variables were compared with Student t test or chi 2 analysis -Fisher 's exact test , respectively . RESULTS The clinical use of tocolysis in symptomatic placenta previa was associated with a clinical ly significant delay of preterm delivery . Significant improvement in clinical parameters such as interval from admission to delivery ( 39.2 vs 26.9 days , p < 0.02 ) and birth weight ( 2520 vs 2124 gm , p < 0.03 ) was observed in the tocolysis group . There was no observed statistical difference between the two treatment groups with regard to incidence of recurrent bleeding , interval from admission to first recurrent bleeding , and need for transfusion . There was a trend for patients with multiple bleeding episodes to have been receiving tocolytic therapy ( p < 0.10 ) . A trend for requiring a postpartum transfusion was also noted in the tocolysis group ( p < 0.09 ) . Treated pregnancies receiving long-term maintenance tocolysis with oral or subcutaneous terbutaline exhibited a greater degree of pregnancy prolongation than those treated with short-term intravenous magnesium alone ( 43.7 vs 15.3 days , p < 0.02 ) . CONCLUSIONS This retrospective analysis suggests that tocolytic intervention in cases of symptomatic preterm previa may be associated with clinical ly significant prolongation of pregnancy and increased birth weight .  Tocolytic therapy in these cases does not appear to have an impact on frequency or severity of recurrent vaginal bleeding . Further prospect i ve analysis may delineate the role of tocolysis in the aggressive expectant management of symptomatic placenta previa 
    Output:
    
Conclusion In women with symptomatic placenta praevia , there is no significant effect on pregnancy prolongation with the use of tocolysis .
Tocolysis has no significant effect on other prenatal , perinatal , neonatal and maternal outcomes among women with symptomatic placenta praevia .