***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 The aim of this study was to compare perinatal outcomes of patients with second-trimester ultrasonographic evidence of preterm dilatation of the internal os treated with cerclage  versus those of patients not treated with cerclage .  STUDY DESIGN From May 1998 through June 1999 patients with ultrasonographic evidence of preterm dilatation of the internal os between 16 and 24 weeks ' gestation were r and omly assigned to receive a McDonald cerclage or no cerclage .  Before r and om assignment all patients underwent amniocentesis and urogenital cultures and then received 48 hours of therapy with indomethacin and antibiotics . After treatment each patient was followed up as an outpatient with bed rest and weekly ultrasonographic evaluation . RESULTS Of the 61 patients 31 were r and omly assigned to cerclage and 30 were r and omly assigned to no cerclage . There were no differences between groups with respect to maternal demographic characteristics , risk factors for preterm birth , cervical measurements , rescue procedures , readmission , chorioamnionitis , and abruptio placentae . The mean gestational age at delivery ( 33.5 + /- 6.3 weeks ) and the perinatal death rate ( 12 . 9 % ) in the cerclage group were similar to the mean gestational age at delivery ( 34.7 + /- 4.7 weeks ; P = .4 ) and the perinatal death rate ( 10.0 % ; P = .9 ) in the no-cerclage group . CONCLUSION Treatment with McDonald cerclage of preterm dilatation of the cervix detected ultrasonographically during the second trimester did not improve perinatal outcomes Objective . To assess efficacy and tolerability of vaginal compared with intramuscular progesterone in reducing the rate of recurrent  preterm birth before 34 weeks of gestation . Design . Prospect i ve r and omized study . Setting . Obstetrics and Gynecology Department , Armed Forces Hospital Southern Region , Kingdom of Saudi Arabia . Sample . Five‐hundred and eighteen women with a prior history of preterm birth . Methods . Women were r and omized to receive either 90 mg of vaginal progesterone gel once daily or 250 mg of intramuscular progesterone weekly . Treatment began between 14 and 18 weeks of gestation and continued until 36 complete weeks of gestation , delivery or the occurrence of premature rupture of membranes . Main outcome measures . The primary outcome measure was delivery before 34 weeks of gestation . The secondary outcome measures were PTB between 34 and 37 weeks of gestation and neonatal outcomes including birthweight , neonatal death , and the need for admission to the neonatal intensive care unit . Results . The baseline characteristics of the study participants were similar . Two‐hundred and thirty‐eight ( 94.1 % ) patients in the vaginal group and 226 ( 90.8 % ) patients in the intramuscular group were compliant with their medications . Vaginal progesterone was associated with a lower percentage of deliveries before 34 weeks of gestation than the intramuscular preparation ( p= 0.02 ) . This association was also observed at 28 and 32 weeks of gestation ( p= 0.04 ) . Adverse effects were reported in 14.1 % of patients in the intramuscular group , but in only 7.5 % of patients in the vaginal group ( p= 0.017 ) . Conclusions . Vaginal progesterone was more effective than intramuscular progesterone for the prevention of preterm birth and had fewer adverse effects OBJECTIVE The purpose of this guideline is to provide a framework that clinicians can use to determine which women are at greatest risk of having cervical insufficiency and in which set of circumstances a cerclage is of potential value . EVIDENCE Published literature was retrieved through search es of PubMed or MEDLINE , CINAHL , and The Cochrane Library in 2012 using appropriate controlled vocabulary ( e.g. , uterine cervical incompetence ) and key words ( e.g. , cervical insufficiency , cerclage , Shirodkar , cerclage , MacDonald , cerclage , abdominal , cervical length , mid-trimester pregnancy loss ) . Results were restricted to systematic review s , r and omized control trials/controlled clinical trials , and observational studies . There were no date or language restrictions . Search es were up date d on a regular basis and incorporated in the guideline to January 2011 . Grey ( unpublished ) literature was identified through search ing the websites of health technology assessment and health technology-related agencies , clinical practice guideline collection s , clinical trial registries , and national and international medical specialty societies . VALUES The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care ( Table ) . Recommendations 1 . Women who are pregnant or planning pregnancy should be evaluated for risk factors for cervical insufficiency . A thorough medical history at initial evaluation may alert clinicians to risk factors in a first or index pregnancy . ( III-B ) 2 . Detailed evaluation of risk factors should be undertaken in women following a mid-trimester pregnancy loss or early premature delivery , or in cases where such complications have occurred in a preceding pregnancy . ( III-B ) 3 . In women with a history of cervical insufficiency , urinalysis for culture and sensitivity and vaginal cultures for bacterial vaginosis should be taken at the first obstetric visit and any infections so found should be treated . ( I-A ) 4 . Women with a history of three or more second-trimester pregnancy losses or extreme premature deliveries , in whom no specific cause other than potential cervical insufficiency is identified , should be offered elective cerclage at 12 to 14 weeks of gestation . ( I-A ) 5 . In women with a classic history of cervical insufficiency in whom prior vaginal cervical cerclage has been unsuccessful , abdominal cerclage can be considered in the absence of additional mitigating factors . ( II-3C ) 6 . Women who have undergone trachelectomy should have  abdominal cerclage placement . ( II-3C ) 7 . Emergency cerclage may be considered in women in whom the cervix has dilated to < 4 cm without contractions before 24 weeks of gestation . ( II-3C ) 8 . Women in whom cerclage is not considered or justified , but whose history suggests a risk for cervical insufficiency ( 1 or 2 prior mid-trimester losses or extreme premature deliveries ) , should be offered serial cervical length assessment by ultrasound . ( II-2B ) 9 . Cerclage should be considered in singleton pregnancies in women with a history of spontaneous preterm birth or possible cervical insufficiency if the cervical length is ≤ 25 mm before 24 weeks of gestation . ( I-A ) 10 . There is no benefit to cerclage in a woman with an incidental finding of a short cervix by ultrasound examination but no prior risk factors for preterm birth . ( II-1D ) 11 . Present data do not support the use of  elective cerclage in multiple gestations even when there is a history of preterm birth ; therefore , this should be avoided . ( I-D ) 12 . The literature does not support the insertion of cerclage in multiple gestations on the basis of cervical length . ( II-1D ) OBJECTIVE The objective of the study was to evaluate the efficacy of 17 alpha-hydroxyprogesterone caproate ( 17OHP-C ) in prolonging gestation in patients with a short cervix and other risk factors for preterm delivery , such as previous preterm birth , cervical surgery , uterine anomalies , or prenatal diethylstilbestrol ( DES ) exposure . STUDY DESIGN This open-label , multicenter , r and omized controlled trial included asymptomatic singleton pregnancies from 20(+0 ) through 31(+6 ) weeks of gestation with a cervical length less than 25 mm and a history of preterm delivery or cervical surgery or uterine malformation or prenatal DES exposure . R and omization assigned them to receive ( or not ) 500 mg of intramuscular 17OHP-C weekly until 36 weeks . The primary outcome was time from r and omization to delivery . RESULTS After enrolling 105 patients , an interim analysis demonstrated the lack of efficacy of 17OHP-C in prolonging pregnancy . The study was discontinued because of futility . The groups were similar for maternal age , body mass index , parity , gestational age at inclusion , history of uterine anomalies , DES syndrome , previous preterm delivery or midtrimester abortion , and cervical length at r and omization . The enrollment-to-delivery interval did not differ between patients allocated to 17OHP-C ( n = 51 ) and those allocated to the control group ( n = 54 ) ( median [ interquartile range ] time to delivery : 77 [ 54 - 103 ] and 74 [ 52 - 99 ] days , respectively ) . The rate of preterm delivery less than 37 ( 45 % vs 44 % , P > .99 ) , less than 34 ( 24 % vs 30 % , P = .51 ) , or less than 32 ( 14 % vs 20 % , P = .44 ) weeks was similar in patients allocated to 17OHP-C and those in the control group . CONCLUSION 17OHP-C did not prolong pregnancy in women with singleton gestations , a sonographic short cervix , and other risk factors of preterm delivery ( prior history , uterine malformations , cervical surgery , or prenatal DES exposure ) OBJECTIVE To determine the effectiveness of cerclage pessary in the prevention of  preterm birth in asymptomatic Chinese women with a short cervix at 20 to 24 weeks . METHODS Low-risk women carrying singleton pregnancies were screened with transvaginal ultrasound , and those with a cervical length < 25 mm at 20 to 24 weeks were recruited into a r and omized controlled trial , comparing the prophylactic use of cerclage pessary with expectant management . The analysis was by intent-to-treat . The primary outcome measure was preterm delivery before 34 weeks . RESULTS Among 4438 screened women , 203 women ( 4.6 % ) met the inclusion criteria and 108 ( 58 % ) consented for the study . A total of 53 and 55 women were allocated to pessary and control groups , respectively . There was no difference in background demographics , including the mean cervical length ( 19.6 mm versus 20.5 mm ) and the mean gestational age at r and omization ( both 21.9 weeks ) . Delivery before 34 weeks occurred in 9.4 % and 5.5 % ( p = 0.46 ) in the pessary and the control groups , respectively . No differences in major side effects were noted between the groups . CONCLUSION In our population , < 5 % had a cervical length of less than 25 mm at 20 to 24 weeks ' gestation . The prophylactic use of cerclage pessary did not reduce the rate of preterm delivery before 34 weeks Background  Preterm birth is a worldwide health concern due to its various negative consequences . Therefore , the prevention of preterm birth is a top priority for healthcare systems in all countries . Objective To compare the effectiveness of vaginal versus intramuscular progesterone in the prevention of preterm delivery . Methods This r and omized clinical trial was conducted at Shahid Sadoughi Hospital in Yazd , Iran , from November 21 , 2012 to January 20 , 2015 . Seventy-eight pregnant women with singleton pregnancy and one risk factor of preterm delivery were included in the study . The subjects were assigned r and omly to two groups , with group one receiving Cyclogest and group two receiving 17-α hydroxyprogesterone caproate . Subsequently , we analyzed drug complications during pregnancy , delivery time , neonatal outcomes , and patients ’ satisfaction among the two groups . The data were analyzed using SPSS version 16 . We used descriptive statistics , chi-squared , t-test , and ANOVA for the analyses of primary and secondary outcomes . Results Among the 39 births in group one , 33.3 % occurred preterm , and , among the 39 births in group two , 30.7 % occurred preterm ( < 37 weeks ) . The mean gestational ages at delivery in groups 1 and 2 were 37.07 ± 2.23 and 36.81 ± 2.77 weeks , respectively ( p = 0.765 ) . Other variables were not significantly different between the two groups , including birth weight ( p = 0.745 ) , Apgar scores for the first and fifth minutes ( p = 0.574 , 0.630 ) , length of stay in the neonatal intensive care unit ( NICU ) when the newborns needed hospitalization ( p = 0.358 ) , and the patients ’ satisfaction with the drugs that were used ( p = 0.615 ) . Conclusions In this study , vaginal progesterone and intramuscular progesterone  had the same levels of effectiveness , safety and acceptance by patients in the prevention of preterm delivery . Therefore , both can be used for this purpose in clinical practice s , but more studies are needed OBJECTIVE The purpose of this study was to evaluate the effect of prophylactic vaginal progesterone in decreasing preterm birth rate in a high-risk population . STUDY DESIGN A r and omized , double-blind , placebo-controlled study included 142 high-risk singleton pregnancies .  Progesterone ( 100 mg ) 
    Output:
    
We found similar results in the subgroup with previous PTB , but only a reduction of PTB < 34 weeks in women with a short cervix .
Pessary showed inconsistent benefit and cerclage did not reduce PTB < 37 or < 34 weeks .
Progesterone was the best intervention for preventing PTB in singleton pregnancies at risk , reducing PTB < 34 weeks , < 37 weeks , neonatal demise and other sequelae .
TWEETABLE ABSTRACT Progesterone was better than cerclage and pessary to prevent preterm birth , neonatal death and more in network meta- analysis