title: Updated reference ranges for the ductus venosus pulsatility index at 11-13 weeks.
abstract: OBJECTIVE
  To update the reference ranges for the ductus venosus pulsatility index (DVPI) at 11+0 to 13+6 gestational weeks.
  
  
  METHODS
  DVPI was calculated in 14,444 singleton fetuses at 11+0 to 13+6 weeks in two Fetal Medicine Centers, during a 4-year period. Using previously described medians, DVPI evolution was assessed both over the study period on a yearly basis and over gestation, grouping fetuses according to 5-mm crown-rump length (CRL) ranges. Weighted DVPI medians, the 5th and 95th percentiles and distribution parameters for unaffected and trisomy 21 fetuses were newly calculated.
  
  
  RESULTS
  A significant DVPI multiple of the median decrease was observed over both the study period (p < 0.01) and over gestation (p < 0.01) using previous medians, in the two centers. Newly calculated weighted medians were lower than those previously described, decreasing with CRL. Distribution parameters calculated using the new medians were different from those previously described.
  
  
  CONCLUSIONS
  DVPI reference ranges were lower than those previously reported and decreased with CRL. Updated medians and distribution parameters should be considered to include the DVPI as a Gaussian marker in trisomy 21 screening and for quality control purposes.
authors.affiliation: Ultrasound Unit, Department of Obstetrics and Gynecology, Hospital Sant Joan de Déu, Esplugues de Llobregat, Spain. jsabria@hsjdbcn.org
authors.forename: Joan
authors.initials: J
authors.lastname: Sabria
authors.forename: Carmina
authors.initials: C
authors.lastname: Comas
authors.forename: Carles
authors.initials: C
authors.lastname: Barceló-Vidal
authors.forename: Raul
authors.initials: R
authors.lastname: Garcia-Posada
authors.forename: Monica
authors.initials: M
authors.lastname: Echevarria
authors.forename: Maria Dolors
authors.initials: MD
authors.lastname: Gomez-Roig
authors.forename: Antoni
authors.initials: A
authors.lastname: Borrell
mesh_terms: D000328:Adult; D015415:Biomarkers; D018568:Crown-Rump Length; D004314:Down Syndrome / Q000000981:diagnostic imaging / Q000196:embryology / Q000503:physiopathology; D005260:Female; D047109:Fetal Development; D006801:Humans; D016011:Normal Distribution; D011169:Portal Vein / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology* / Q000503:physiopathology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011673:Pulsatile Flow; D012016:Reference Values; D012079:Renal Circulation; D013030:Spain; D016216:Ultrasonography, Prenatal
chemical_list: D015415:Biomarkers