title: First trimester maternal serum placental growth factor levels in twin pregnancies.
abstract: BACKGROUND
  An understanding of the normal behavior of biochemical markers in twin pregnancies is necessary in order to offer prenatal screening to this subgroup. This study investigates the levels of first trimester maternal serum placental growth factor (PlGF) in twin and singleton pregnancies.
  
  
  METHODS
  The PlGF concentrations were measured by an automated assay in the first trimester maternal serum of 440 dichorionic twin, 116 monochorionic twin, and 607 singleton pregnancy samples thawed from frozen storage.
  
  
  RESULTS
  The PlGF concentrations in singleton levels were predicted by gestational age, maternal ethnicity, and smoking status. Following the correction for these variables, PlGF levels were, on average, 41% higher in dichorionics, but only 16% higher in monochorionics, compared to singleton pregnancies.
  
  
  CONCLUSIONS
  First trimester maternal serum PlGF levels are increased in twin pregnancies compared with singleton pregnancies, but to less of an extent than is common with other screening markers, especially in monochorionic twins.
authors.affiliation: Prenatal Research Unit, Department of Clinical Biochemistry, King George Hospital, Goodmayes, UK.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Cowans
authors.forename: Kevin
authors.initials: K
authors.lastname: Spencer
mesh_terms: D000328:Adult; D004200:Diseases in Twins / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D005865:Gestational Age; D006801:Humans; D009035:Mothers; D000072483:Placenta Growth Factor; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood*; D059285:Pregnancy, Twin / Q000097:blood*; D011296:Prenatal Diagnosis
chemical_list: C000608036:PGF protein, human; D011257:Pregnancy Proteins; D000072483:Placenta Growth Factor