title: First-trimester biochemistry and outcomes in twin pregnancy.
abstract: OBJECTIVE
  To examine the relationship between levels of first-trimester serum analytes used in aneuploidy risk assessment and obstetric outcomes in twin pregnancy.
  
  
  METHODS
  Twin pregnancies undergoing first-trimester risk assessment from 2003 to 2005 were identified. Pregnancy-associated plasma protein A (PAPP-A) and free beta-human chorionic gonadotropin (beta-hCG) were measured at 9-14 weeks. The association between extreme biochemical values (< 5th and > 95th percentile) and adverse outcomes was examined. Fisher's exact test and Mann-Whitney U were used for comparison.
  
  
  RESULTS
  A total of 326 pregnancies were included. Median maternal age was 35 years. Median gestational age at delivery was 36 weeks. There were no significant associations between extreme free beta-hCG or high PAPP-A values and the rates of any adverse outcomes. Low PAPP-A (< 0.52 multiples of the median) was associated with higher rates of discordant growth (50% vs. 13%; p = 0.001) and hypertensive disorders of pregnancy (41.2% vs. 15.5%, p = 0.01).
  
  
  CONCLUSIONS
  In twin pregnancies, low PAPP-A is associated with discordant growth and hypertensive disorders.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Weill Medical College of Cornell University, New York, New York, USA. stchasen@med.cornell.edu
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chasen
authors.forename: Stacy
authors.initials: S
authors.lastname: Martinucci
authors.forename: Sriram C
authors.initials: SC
authors.lastname: Perni
authors.forename: Robin B
authors.initials: RB
authors.lastname: Kalish
mesh_terms: D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro; D047109:Fetal Development; D005865:Gestational Age; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000097:blood; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011272:Pregnancy, Multiple / Q000097:blood*; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D014427:Twins
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A