title: Cervical length as a prognostic factor for preterm delivery in twin-to-twin transfusion syndrome treated by fetoscopic laser coagulation of chorionic plate anastomoses.
abstract: OBJECTIVE
  To evaluate the risk of spontaneous preterm delivery in relation to cervical length in severe cases of twin-to-twin transfusion syndrome (TTTS) diagnosed before 26 weeks of gestation and treated by laser coagulation of the intertwin placental anastomoses.
  
  
  METHODS
  This was an observational study of cases of severe TTTS diagnosed before 26 weeks of gestation and treated by fetoscopic laser coagulation between January 2002 and December 2003 in three centers. Laser was the first-line treatment in all cases. Elective preterm deliveries before 34 weeks' for maternal or fetal indications, including intrauterine death of both fetuses, were excluded. Transvaginal sonographic measurement of cervical length prior to laser treatment and other risk factors of preterm delivery were evaluated by univariate and logistic regression analysis.
  
  
  RESULTS
  Among the 137 women included, the mean cervical length was 32 and 38 mm in women delivering before and at or after 34 weeks, respectively (P < 0.001). For a cervical length of < 30 mm, the risk of delivery before 34 weeks was 74%. Severity of the disease, deepest vertical pool of amniotic fluid and amniotic fluid volume drained after the procedure were not associated with preterm delivery. Logistic regression analysis identified three independent factors to predict preterm delivery: short cervical length (increased risk), parity (increased risk) and intrauterine death of one twin (decreased risk).
  
  
  CONCLUSIONS
  In TTTS treated by laser, without indications for elective preterm birth, cervical length before treatment is significantly associated with gestational age at delivery, and this is independent of parity, intrauterine death of one fetus and other risk factors.
authors.affiliation: Department of Obstetrics and Gynecology, Paris-Ouest University Versailles-St Quentin, Paris, France.
authors.forename: R
authors.initials: R
authors.lastname: Robyr
authors.forename: M
authors.initials: M
authors.lastname: Boulvain
authors.forename: L
authors.initials: L
authors.lastname: Lewi
authors.forename: A
authors.initials: A
authors.lastname: Huber
authors.forename: K
authors.initials: K
authors.lastname: Hecher
authors.forename: J
authors.initials: J
authors.lastname: Deprest
authors.forename: Y
authors.initials: Y
authors.lastname: Ville
mesh_terms: D000328:Adult; D001164:Arteriovenous Fistula / Q000601:surgery; D002584:Cervix Uteri / Q000000981:diagnostic imaging / Q000473:pathology*; D002824:Chorionic Villi / Q000098:blood supply*; D005260:Female; D005330:Fetofetal Transfusion / Q000601:surgery*; D005332:Fetoscopy; D005865:Gestational Age; D006801:Humans; D017075:Laser Coagulation; D011247:Pregnancy; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000000981:diagnostic imaging / Q000473:pathology*; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D016216:Ultrasonography, Prenatal / Q000379:methods