title: Perioperative characteristics associated with preterm birth in twin-twin transfusion syndrome treated by laser surgery.
abstract: OBJECTIVE
  To identify perioperative risk factors for preterm delivery (PTD) in laser-treated patients with twin-twin transfusion syndrome (TTTS).
  
  
  METHODS
  Twin-twin transfusion syndrome patients who underwent laser surgery were followed prospectively. Univariate and multivariate analyses were performed to identify gestational and surgical characteristics associated with preterm delivery.
  
  
  RESULTS
  Of 318 eligible patients, the mean (SD) gestational age of delivery was 32.8 (4.2) weeks. The number of days from laser surgery to delivery had a bimodal distribution; group I delivered within 21 days and group II delivered after 21 days of surgery. Eighteen patients (5.7%) were in group I and demonstrated the following risk factors for delivery within 21 days: incomplete laser surgery suspected (odds ratio [OR], 11.14; P = .0106), preoperative subchorionic hematoma (OR, 7.92, P = .0361), preoperative cervical length <2.0 cm (OR, 4.71; P = .0117), and recipient's maximum vertical pocket ≥14 cm (OR, 3.23; P = .0335). In group II, 92 of 300 patients (30.7%) delivered <32 weeks, and 25 (8.3%) delivered <28 weeks; multivariate logistic regression analyses identified 5 risk factors for delivery <32 weeks: incomplete laser surgery suspected (OR, 10.0; P = .0506); incidental septostomy (OR, 4.4; P = .0009); triplet gestation (OR, 2.6; P = .0689); postoperative membrane detachment (OR, 2.4; P = .0393); and nonposterior placental location (OR, 1.8; P = .0282).
  
  
  CONCLUSIONS
  Timing of delivery after laser for twin-twin transfusion syndrome has a bimodal distribution with distinct gestational and surgical risk factors. This information may be useful in counseling patients and in directing future avenues of research.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Ramen H
authors.initials: RH
authors.lastname: Chmait
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Korst
authors.forename: Arlyn
authors.initials: A
authors.lastname: Llanes
authors.forename: Patrick
authors.initials: P
authors.lastname: Mullin
authors.forename: Richard H
authors.initials: RH
authors.lastname: Lee
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Ouzounian
mesh_terms: D000293:Adolescent; D000328:Adult; D003376:Counseling; D005260:Female; D005330:Fetofetal Transfusion / Q000601:surgery*; D006801:Humans; D053685:Laser Therapy; D016015:Logistic Models; D008875:Middle Aged; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology*; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors
keywords: TTTS; laser surgery; prematurity; preterm birth; twin-twin transfusion syndrome