title: Cerclage for prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination: a randomized trial.
abstract: OBJECTIVE
  The purpose of this study was to determine the efficacy of cerclage and bed rest versus bed rest-only for the prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination.
  
  
  METHODS
  Women with > or =1 of high-risk factors for preterm birth (> or =1 preterm birth at < 35 weeks of gestation, > or =2 curettages, diethylstilbestrol exposure, cone biopsy, Mullerian anomaly, or twin gestation) were screened with transvaginal ultrasonography of the cervix every 2 weeks from 14 weeks of gestation to 23 weeks 6 days of gestation. Enrollment was offered to both asymptomatic women who were at high risk and who were identified to have short cervix (< 25 mm) or significant funneling (>25%) and nonscreened women who were at low risk and who were identified incidentally. The women who gave written consent were assigned randomly to receive either McDonald cerclage or bed rest-only. Both groups received similar counseling and treatment. Primary outcome was preterm birth at < 35 weeks of gestation.
  
  
  RESULTS
  Sixty-one women were assigned randomly. Forty-seven pregnancies (77%) were high-risk singleton gestations. Thirty-one women (51%) were allocated to cerclage, and 30 women (49%) were allocated to bed rest. There were no differences between the groups in demographic characteristics, risk factors, and cervical variables. Preterm birth at < 35 weeks of gestation occurred in 14 women (45%) in the cerclage group and in 14 women (47%) in the bed rest group (relative risk, 0.94; 95% CI, 0.34-2.58). There was no difference in any obstetric or neonatal outcomes. A subanalysis of singleton pregnancies with previous preterm birth at < 35 weeks of gestation and a short cervix of < 25 mm (n = 31 women) also revealed no significant difference in recurrent preterm birth at < 35 weeks of gestation (40% vs 56%; relative risk, 0.52; 95% CI, 0.12-2.17).
  
  
  CONCLUSIONS
  Cerclage did not prevent preterm birth in women with a short cervix. These results should be confirmed by larger trials.
authors.affiliation: Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Berghella
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Odibo
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Tolosa
mesh_terms: D001510:Bed Rest; D023802:Cerclage, Cervical; D002584:Cervix Uteri / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D047928:Premature Birth / Q000517:prevention & control*; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal; D014621:Vagina / Q000000981:diagnostic imaging