title: First trimester biochemical markers in twin pregnancies.
abstract: OBJECTIVE
  Our aim was to investigate the first trimester serum markers and nuchal translucency (NT) measurements in twin pregnancies in our population.
  
  
  METHODS
  We reviewed the results of all double tests that were performed in our hospital over a three-year period. Out of them, we selected all twins and compared them with a group of three times as many singleton controls. NT measurements and the first trimester serum markers from 49 twin pregnancies were compared to those of 147 pregnant women with normal singleton pregnancy
  
  
  RESULTS
  There were no statistically significant differences in age, gestational age and maternal weight between the two groups (p > 0.05). We found similar NT measurements in the two groups. The median MoM of Pregnancy-Associated Plasma Protein A (PAPP-A) and fβ-hCG levels in twins were statistically significantly higher than those in singleton pregnancies. Twelve percent of the twins (12.2%) were the result of assisted reproduction technologies. IVF versus naturally conceived pregnancies showed similar MoM of PAPP-A (2.2 vs. 1.2, respectively) and fβ-hCG (Mann-Whitney U; p = 0.195 and p = 0.958).
  
  
  CONCLUSIONS
  Our study revealed that median PAPP-A and fβ-hCG levels for twins were less than twice those of singleton values.
authors.forename: Sevki
authors.initials: S
authors.lastname: Celen
authors.forename: Yaprak
authors.initials: Y
authors.lastname: Engin-Ustün
authors.forename: Figen
authors.initials: F
authors.lastname: Türkçapar
authors.forename: Ayla
authors.initials: A
authors.lastname: Aktulay
authors.forename: Nafiye
authors.initials: N
authors.lastname: Yilmaz
authors.forename: Ayşegül
authors.initials: A
authors.lastname: Oksüzoğlu
authors.forename: Ozlem
authors.initials: O
authors.lastname: Yörük
authors.forename: Nuri
authors.initials: N
authors.lastname: Danişman
mesh_terms: D015415:Biomarkers / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D005260:Female; D006801:Humans; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D059285:Pregnancy, Twin / Q000097:blood*; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D012016:Reference Values
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A