title: Ultrasonographic findings of placenta lacunae and a lack of a clear zone in cases with placenta previa and normal placenta.
abstract: OBJECTIVE
  To evaluate whether the frequencies of placenta lacunae and lack of a clear zone are higher in cases of placenta previa compared with those without it.
  
  
  METHODS
  Ultrasonographic findings just before delivery, including placenta lacunae and lack of a clear zone were prospectively evaluated in consecutive subjects. After collection, a case-control study with 1:5 matched pairs was conducted. The frequencies of ultrasonographic findings were analyzed in cases with placenta previa and normal placenta.
  
  
  RESULTS
  Seventy cases with placenta previa and 350 cases with normal placentas were observed. Five and zero cases with abnormal placental adherence were observed in cases with placenta previa and normal placenta, respectively. Lack of a clear zone was observed in 60 and 1.5% of cases with and without the placental adherence (p = 0.001). Placenta lacunae and lack of a clear zone were observed in 31.4 and 9.7% of cases with and without placenta previa [odds ratio (OR) 4.2]. Lack of a clear zone was observed in 5.7 and 0.9% of cases with and without placenta previa (OR 7.0).
  
  
  CONCLUSIONS
  Placenta lacunae and lack of a clear zone are frequently observed in placenta previa even when there is no adherence of the placenta.
authors.affiliation: Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan. choko-kuu@mail.goo.ne.jp
authors.forename: Shoko
authors.initials: S
authors.lastname: Hamada
authors.forename: Junichi
authors.initials: J
authors.lastname: Hasegawa
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Nakamura
authors.forename: Ryu
authors.initials: R
authors.lastname: Matsuoka
authors.forename: Kiyotake
authors.initials: K
authors.lastname: Ichizuka
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sekizawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Okai
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D010920:Placenta / Q000000981:diagnostic imaging* / Q000473:pathology; D010921:Placenta Accreta / Q000000981:diagnostic imaging* / Q000473:pathology; D010923:Placenta Previa / Q000000981:diagnostic imaging* / Q000473:pathology; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*