title: Vasa previa is not infrequent.
abstract: OBJECTIVE
  To clarify certain frequency of vasa previa using ultrasonography.
  
  
  METHODS
  Umbilical cord insertion site were examined prospectively by the ultrasound during first trimester in 3647 cases between 2006 and 2011.
  
  
  RESULTS
  10 cases (1: 365) of vasa previa were found. All cases with vasa previa at the delivery had been diagnosed as a lower cord insertion in the uterine cavity in the first trimester, whereas we do not have any misdiagnosed cases.
  
  
  CONCLUSIONS
  Although it is believed that the incidence of vasa previa is very rare, according to our ultrasonographic evaluation vasa previa is not infrequent. Additional systematic identification of umbilical cord abnormalities from early gestation is recommended.
authors: Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan. hasejun@oak.dti.ne.jp
authors: Junichi
authors: J
authors: Hasegawa
authors: Masamitsu
authors: M
authors: Nakamura
authors: Kiyotake
authors: K
authors: Ichizuka
authors: Ryu
authors: R
authors: Matsuoka
authors: Akihiko
authors: A
authors: Sekizawa
authors: Takashi
authors: T
authors: Okai
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D018615:Ultrasonography, Doppler, Color; D016216:Ultrasonography, Prenatal; D014470:Umbilical Cord / Q000000981:diagnostic imaging; D014599:Uterus / Q000000981:diagnostic imaging; D055949:Vasa Previa / Q000000981:diagnostic imaging / Q000453:epidemiology*