title: Mid-second trimester measurement of fetal nasal bone length in the Japanese population.
abstract: OBJECTIVE
  We carried out a preliminary study to compare the nasal bone length (NBL) and biparietal diameter/NBL (BPD/NBL) ratio between the Japanese and white populations.
  
  
  METHODS
  Three hundred and fifty nine (359) singleton fetuses of healthy Japanese couples were examined from June 2004 to October 2005. NBL was measured by the strict midsagittal section. The reference range of NBL was established from cross-sectional data between 15 and 25 weeks' gestation.
  
  
  RESULTS
  The success rate of obtaining reliable NBL was 93% (333/356). There were 330 fetuses (93%) available for constructing a reference range from the population. The median NBL increased from 3.2 mm at 15 weeks' to 7.6 mm at 25 weeks' gestation. The median of BPD/NBL ratio was 9.01.
  
  
  CONCLUSIONS
  We demonstrated that NBL was significantly shorter and BPD/NBL was significantly greater in the Japanese population than those in the white and black populations.
authors.affiliation: Department of Obstetrics and Gynecology, Osaka University Faculty of Medicine, Osaka, Japan. kanagawa@gyne.med.osaka-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kanagawa
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Fukuda
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kinugasa
authors.forename: Mihyon
authors.initials: M
authors.lastname: Son
authors.forename: Koichiro
authors.initials: K
authors.lastname: Shimoya
authors.forename: Yuji
authors.initials: Y
authors.lastname: Murata
authors.forename: Takuhei
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Isaka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nagamatsu
mesh_terms: D000293:Adolescent; D000328:Adult; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007564:Japan; D009295:Nasal Bone / Q000000981:diagnostic imaging / Q000196:embryology*; D049451:Nomograms; D011247:Pregnancy; D012016:Reference Values; D016216:Ultrasonography, Prenatal