***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 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 Objective : The aim of this study was to evaluate the efficacy and safety of a noninvasive cerclage pessary in the management of cervical incompetence . Methods : This is a prospect i ve cohort study of all pregnant women treated for cervical incompetence during a 4-year period . Women with known risk factors for preterm delivery had transvaginal ultrasonography every 2–3 weeks after 17–19 weeks of gestation . Those with progressive shortening of cervix diagnosed before 30 weeks were treated with a cerclage pessary when the cervical length was ≤25 mm . The pessary was electively removed at 34–36 weeks . The course and outcome of pregnancy were recorded . Results : Thirty-two women were treated with a cerclage pessary . There were nine twin and two triplet pregnancies . Fifteen ( 47 % ) had two or more risk factors for preterm delivery  . The mean gestational age at cerclage was 23 ( 17–29 ) weeks , cervical length 17 ( 5–25 ) mm . Two women required delivery before the onset of labor due to severe intrauterine growth restriction and one due to HELLP syndrome . These were excluded from further analysis . In the remaining 29 women , the interval between cerclage and delivery was 10.4 ( 2–19 ) weeks , mean gestational age at delivery 34 ( 22–42 ) weeks , and birth weight 2,255 ( 410–4,045 ) g. Thirteen ( 45 % ) women delivered before 34 weeks . There were a total of 35 live-born infants and four intrapartum fetal deaths ( all between 22 and 25 weeks gestation ) . All women complained of increased vaginal discharge , but no other significant complications were observed that could be attributed to the use of pessary . Conclusion : Cerclage pessary may be useful in the management of  cervical incompetence . Whether it can be a noninvasive alternative to surgical cerclage merits further investigation BACKGROUND Most previous studies of the use of cervical pessaries were either retrospective or case controlled and their results showed that this intervention might be a preventive strategy for women at risk of preterm birth ; no r and omised controlled trials have been undertaken . We therefore undertook a r and omised , controlled trial to investigate whether the insertion of a cervical pessary in women with a short cervix identified by use of routine transvaginal scanning at 20 - 23 weeks of gestation reduces the rate of early preterm delivery . METHODS The Pesario Cervical para Evitar Prematuridad ( PECEP ) trial was undertaken in five hospitals in Spain . Pregnant women ( aged 18 - 43 years ) with a cervical length of 25 mm or less were r and omly assigned according to a computer-generated allocation sequence by use of central telephone in a 1:1 ratio to the  cervical pessary or expectant management ( without a cervical pessary ) group . Because of the nature of the intervention , this study was not masked . The primary outcome was spontaneous delivery before 34 weeks of gestation . Analysis was by intention to treat . This study is registered with Clinical Trials.gov , number NCT00706264 . FINDINGS 385 pregnant women with a short cervix were assigned to the pessary ( n=192 ) and expectant management groups ( n=193 ) , and 190 were analysed in each group .  Spontaneous delivery before 34 weeks of gestation was significantly less frequent in the pessary group than in the expectant management group ( 12 [ 6 % ] vs 51 [ 27 % ] , odds ratio 0·18 , 95 % CI 0·08 - 0·37 ; p<0·0001 ) . No serious adverse effects associated with the use of a cervical pessary were reported . INTERPRETATION Cervical pessary use could prevent preterm birth in a population of appropriately selected at-risk women previously screened for cervical length assessment at the midtrimester scan . FUNDING Instituto Carlos III Most systematic review s rely substantially on the assessment of the method ological quality of the individual trials . The aim of this study was to obtain consensus among experts about a set of generic core items for quality assessment of r and omized clinical trials ( RCTs ) . The invited participants were experts in the field of quality assessment of RCTs . The initial item pool contained all items from existing criteria lists . Subsequently , we reduced the number of items by using the Delphi consensus technique . Each Delphi round comprised a question naire , an analysis , and a feedback report . The feedback report included staff team decisions made on the basis of the analysis and their justification . A total of 33 international experts agreed to participate , of whom 21 completed all question naires . The initial item pool of 206 items was reduced to 9 items in three Delphi rounds . The final criteria list ( the Delphi list ) was satisfactory to all participants . It is a starting point on the way to a minimum reference st and ard for RCTs on many different research topics . This list is not intended to replace , but rather to be used alongside , existing criteria lists Abstract Objective : The purpose was to determine the effect of vaginal pessaries in patients at risk for spontaneous preterm birth ( SPB ) . Study Design : Transvaginal sonography ( TVS ) was longitudinally performed to measure cervical length ( CL ) in 258 singleton at risk for SPB and 282 twin pregnancies . Pairs with or without treatment were matched for gestational age and the CL at examination . Results : In 4 singleton and 7 twin pregnancies the CL was < 15 mm before 24 weeks , the mean interval between  pessary insertion and delivery was 13 + 2 and 12 + 5 weeks respectively . For the matched control analysis , 12 pairs with singleton and 23 pairs with twin pregnancies were compared . For singleton pregnancies , the mean interval between TVS and delivery was 99 ( 70–134 ) days in the treatment and 67 ( 2–130 ) days in the control group ( p = 0.0184 ) , the mean gestational age at delivery was 38 ( 36 + 6–41 ) and 33 + 4 ( 26–38 ) weeks respectively ( p = 0.02 ) . For twin pregnancies , the interval was 85 ( 43–129 ) days in the treatment and 67 ( 21–100 ) days in the control group ( p = 0.001 ) , gestational age at delivery was 35 + 6 ( 33–37 + 4 ) and 33 + 2 ( 24 + 4–37 + 2 ) respectively ( p = 0.02 ) . Within singleton pregnancies with pessary , there was no SPB < 36 weeks compared to 6/12 cases in the control group ( p < 0.001 ) . Within twin pregnancies , the rates were 8/23 cases with SPB < 36 weeks but none < 32 weeks , compared to 12/23 cases with SPB < 36 weeks and 7/23 cases < 32 weeks in the control group ( p < 0.001 ) . Conclusions : Insertion of a vaginal pessary may be a cost-effective preventive treatment in patients at risk for SPB . Prospect i ve controlled trials are needed BACKGROUND The role of the cervix in the pathogenesis of  premature delivery  is controversial . In a prospect i ve , multicenter study of pregnant women , we used vaginal ultrasonography to measure the length of the cervix ; we also documented the incidence of spontaneous delivery before 35 weeks ' gestation . METHODS At 10 university-affiliated prenatal clinics , we performed vaginal ultrasonography at approximately 24 and 28 weeks of gestation in women with singleton pregnancies . We then assessed the relation between the length of the cervix and the risk of spontaneous preterm delivery . RESULTS We examined 2915 women at approximately 24 weeks of gestation and 2531 of these women again at approximately 28 weeks .  Spontaneous preterm delivery ( at less than 35 weeks ) occurred in 126 of the women ( 4.3 percent ) examined at 24 weeks . The length of the cervix was normally distributed at 24 and 28 weeks ( mean [ + /- SD ] , 35.2 + /- 8.3 mm and 33.7 + /- 8.5 mm , respectively ) . The relative risk of preterm delivery increased as the length of the cervix decreased . When women with shorter cervixes at 24 weeks were compared with women with values above the 75th percentile , the relative risks of preterm delivery among the women with shorter cervixes were as follows : 1.98 for cervical lengths at or below the 75th percentile ( 40 mm ) , 2.35 for lengths at or below the 50th percentile ( 35 mm ) , 3.79 for lengths at or below the 25th percentile ( 30 mm ) , 6.19 for lengths at or below the 10th percentile ( 26 mm ) , 9.49 for lengths at or below the 5th percentile ( 22 mm ) , and 13.99 for lengths at or below the 1st percentile ( 13 mm ) ( P < 0.001 for values at or below the 50th percentile ; P = 0.008 for values at or below the 75th percentile ) . For the lengths measured at 28 weeks , the corresponding relative risks were 2.80 , 3.52 , 5.39 , 9.57 , 13.88 , and 24.94 ( P < 0.001 for values at or below the 50th percentile ; P = 0.003 for values at the 75th percentile ) . CONCLUSIONS The risk of spontaneous preterm delivery is increased in women who are found to have a short cervix by vaginal ultrasonography during pregnancy To evaluate the  efficiency of cerclage or pessary a prospect i ve r and om study has been done from 1982 to 1983 .  Pelvic score of Bishop and tocolysis index of Baumgarten were used to define the situation at the beginning . Success has been estimated with help of neonatal parameters ( birth weight , Apgar score and RDS-morbidity ) and final gestational week . Both methods are equal in their effects Objective . The Arabin pessary may be beneficial in the treatment of cervical incompetence . The aim of the study was to analyse the efficacy of the treatment method of pregnant women with cervical incompetence . Methods . A non-r and omised study performed in the obstetrical wards in Lodz , Pol and utilising 54 pregnant women with cervical incompetence was developed to assess the efficiency of treatment methods of cervically incompetent women . These women were diagnosed by vaginal ultrasound examination during the course of the study . Patients with a cervical length of 15–30 mm before 28 weeks an Arabin cervical pessary were inserted , women whose cervical length was less than 15 mm were treated with cervical cerclage . The main end points of the study were preterm or term delivery . Results . In the Arabin pessary group , 1.9 % of women delivered before the 29th week of gestation and 83.3 % of women delivered after 37 weeks of pregnancy . Eighty-seven per cent of pregnant women treated for cervical incompetence by Arabin pessary delivered by normal spontaneous labour , 1.9 % delivered by forceps labour and 11.1 % of patients by caesarean section . Among pregnant women treated by Arabin pessary , 3.7 % of newborns were estimated as having a score of 0–4 on the Apgar scale , 13 % a score of 5–7 and 83.3 % a score of 8–10 . Conclusions . Cervical incompetence treatment effectively prolongs the duration of gestation . Application of the Arabin pessary is an effective method of cervical incompetence treatment 
    Output:
    
Available r and omized and nonr and omized studies indicate potential effectiveness of a cervical pessary in the prevention of preterm birth .