title: Short cervical lengths initially detected in mid-trimester and early in the third trimester in asymptomatic twin gestations: Association with histologic chorioamnionitis and preterm birth.
abstract: OBJECTIVE
  To determine whether short cervical lengths (≤20 mm) that were initially detected in mid-trimester and early in the third trimester are independently associated with increased risks of subsequent histologic chorioamnionitis and spontaneous preterm birth (SPTB, defined as a delivery before 34 weeks) in asymptomatic women with twin pregnancies.
  
  
  METHODS
  This is a prospective study including 292 consecutive asymptomatic women with twin gestations. Cervical length measurements were carried out at 20 to 24 weeks' gestation and at 28 to 32 weeks' gestation. Both placentas of each twin pair were examined histologically after delivery. The generalized estimation equations models and logistic regression analysis were used for statistical analyses.
  
  
  RESULTS
  Multivariable generalized estimation equations analysis revealed that short cervical length at mid-trimester was independently associated with an increased risk for subsequent histologic chorioamnionitis, whereas short cervical length initially detected early in the third trimester was not. By using the likelihood of SPTB as an outcome variable, multivariable logistic regression analysis indicated that short mid-trimester cervical length and histologic chorioamnionitis were independently associated with a greater risk for SPTB. Similarly, based on the multivariable analysis, a short third trimester cervical length was independently and significantly associated with a greater risk for SPTB.
  
  
  CONCLUSIONS
  In asymptomatic women with twin pregnancies, a short mid-trimester cervical length is independently associated with an increased risk of both subsequent histologic chorioamnionitis and SPTB, whereas a short cervical length initially detected early in the third trimester is independently associated with preterm delivery, but not subsequent histologic chorioamnionitis.
authors.affiliation: Department of Obstetrics and Gynecology, Inje University College of Medicine, Ilsan-Paik Hospital, Gyeonggi, Republic of Korea.|Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jeong Woo
authors.initials: JW
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea.|Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Kyo Hoon
authors.initials: KH
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Jung
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Soo-Hyun
authors.initials: SH
authors.lastname: Cho
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Ji Ae
authors.initials: JA
authors.lastname: Jang
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Ha-Na
authors.initials: HN
authors.lastname: Yoo
mesh_terms: D002821:Chorioamnionitis / Q000473:pathology*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D059285:Pregnancy, Twin; D047928:Premature Birth; D011446:Prospective Studies; D056910:Republic of Korea