title: Clinical significance of first trimester crown-rump length disparity in dichorionic twin gestations.
abstract: OBJECTIVE
  The purpose of this study was to determine the clinical significance of first trimester crown-rump disparity in dichorionic twin gestations.
  
  
  METHODS
  Ultrasound examinations of dichorionic twin pregnancies between 11 and 14 weeks of gestation were evaluated for growth discordance using crown-rump length. Medical records were reviewed for antenatal complications that included spontaneous abortion, fetal death, fetal structural or chromosomal anomalies, and preterm delivery. Fisher's exact test was used for statistical analysis; a probability value of <.05 was considered significant.
  
  
  RESULTS
  Of 159 twin pregnancies, there were 7 fetal structural anomalies, 2 fetal chromosomal anomalies, 5 second-trimester spontaneous abortions, 3 second-trimester fetal deaths, and 1 third-trimester fetal death. Pregnancies that were complicated by fetal structural or chromosomal anomalies had significantly greater median crown-rump length discordance than pregnancies without fetal anomalies (4.0 mm vs 2.0 mm; P = .02). Crown-rump length discordance >10%, which is the 90th percentile for intertwin crown-rump length disparity in our population, was associated with a significantly higher incidence of fetal anomalies (22.2% vs 2.8%; P = .01).
  
  
  CONCLUSIONS
  First trimester crown-rump length disparity in dichorionic twin gestations is associated with an increased risk of fetal structural and chromosomal anomalies.
authors.affiliation: Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Weill Medical College of Cornell University, 525 East 68th Street, New York, NY 10021, USA.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Kalish
authors.forename: Meruka
authors.initials: M
authors.lastname: Gupta
authors.forename: Sriram C
authors.initials: SC
authors.lastname: Perni
authors.forename: Seth
authors.initials: S
authors.lastname: Berman
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chasen
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology; D018568:Crown-Rump Length; D005260:Female; D005313:Fetal Death / Q000453:epidemiology; D047109:Fetal Development; D006801:Humans; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011272:Pregnancy, Multiple; D012372:ROC Curve; D027724:Reproductive Techniques, Assisted; D014427:Twins; D016216:Ultrasonography, Prenatal