title: First trimester maternal serum placental protein 13 levels in singleton vs. twin pregnancies with and without severe pre-eclampsia.
abstract: OBJECTIVE
  To determine first trimester maternal serum placental protein 13 (PP13) in singletons vs. twins with and without severe preeclampsia (PE).
  
  
  METHODS
  Serum samples were prospectively collected at 8-14 weeks of gestation. PP13 was determined by solid-phase immunoassay. Patients were recruited in community clinics throughout the country, and from the twin antenatal assessment clinic in Assaf Harofeh Medical Center, Zerifin, Israel. Demographics, medical, and pregnancy history were obtained at enrollment. Pregnancy outcome was collected after delivery. PP13 was compared by the Wilcoxon rank sum test.
  
  
  RESULTS
  In singletons, PP13 declined with maternal weight and was lower in in vitro fertilization. Levels were converted into multiples of the median (MoMs) accordingly. In twins, the median was 1.74 MoM (n=76) vs. 1.00 in singletons (n=676, P<0.0001). Among twins with severe PE (n=10), the median was 1.53 MoM vs. 1.74 in unaffected twins (P=0.10), and 2.26 (n=6) for mild PE (P=0.30). Among singletons with severe PE, the median was 0.44 MoM (n=26, P<0.0001), and for mild PE 0.62 (n=17, P<0.001).
  
  
  CONCLUSIONS
  PP13 is higher in twins than singletons, corresponding to the larger placental mass. Among singletons with severe PE, levels were significantly reduced, however, among twins, only a non-significant tendency for a reduction was recorded, and warrants further investigation in a larger series.
authors.affiliation: Ultrasound Institute, Department of Obstetrics and Gynecology, Assaf Harofeh Medical Center, Zerifin and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ran
authors.initials: R
authors.lastname: Svirsky
authors.forename: Hamutal
authors.initials: H
authors.lastname: Meiri
authors.forename: Ayelet
authors.initials: A
authors.lastname: Herzog
authors.forename: Vered
authors.initials: V
authors.lastname: Kivity
authors.forename: Howard
authors.initials: H
authors.lastname: Cuckle
authors.forename: Ron
authors.initials: R
authors.lastname: Maymon
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro; D037161:Galectins / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D008875:Middle Aged; D011225:Pre-Eclampsia / Q000097:blood* / Q000209:etiology / Q000517:prevention & control; D011247:Pregnancy; D011256:Pregnancy Outcome; D011257:Pregnancy Proteins / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood; D059285:Pregnancy, Twin / Q000097:blood*; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D037161:Galectins; C038195:LGALS13 protein, human; D011257:Pregnancy Proteins