title: Which type of placenta previa requires blood transfusion more frequently? A new concept of indiscernible edge total previa.
abstract: OBJECTIVE
  During cesarean section (CS) for placenta previa (PP), the size/area/portion of the lower uterine segment occupied by the placenta may affect the bleeding amount and the subsequent need for a blood transfusion (BT). We propose a new concept, indiscernible edge total PP (IEPP), when vaginal ultrasound does not discern the lower placental edge because the placenta covers the visible lower segment. We characterized IEPP, focusing on its allogeneic BT requirement.
  
  
  METHODS
  We classified PP (n = 307) into four types: marginal, partial, discernible edge total PP (DEPP) and IEPP: internal ostium (os)-placental edge distance measurable or unmeasurable on vaginal ultrasound in DEPP or IEPP, respectively. We determined the clinical characteristics according to the four types; the relationship between the intraoperative blood loss and os-edge distance in DEPP; and risk factors for allogeneic BT.
  
  
  RESULTS
  The following were significantly higher/larger in cases of IEPP: previous CS; anterior placentation; lacunae; elective cesarean hysterectomy; intraoperative blood loss; autologous BT; allogeneic BT; intensive care unit admission; and an abnormally invasive placenta (AIP). In DEPP, the os-edge distance was weakly correlated with the bleeding amount (r = 0.214). Multivariate logistic regression analysis showed that previous CS, lacunae, AIP and IEPP were independent risk factors for allogeneic BT (odds ratios 3.8, 3.1, 13.8 and 4.6, respectively). After excluding patients undergoing hemostatic procedures during CS, IEPP remained the only independent risk factor for allogeneic BT (odds ratio 5.2).
  
  
  CONCLUSIONS
  The new concept of IEPP may be useful for predicting BT in CS for patients with PP.
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, Tochigi, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Baba
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, Tochigi, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, Tochigi, Japan.
authors.forename: Akihide
authors.initials: A
authors.lastname: Ohkuchi
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, Tochigi, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Usui
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, Tochigi, Japan. matsushi@jichi.ac.jp.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsubara
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging; D000328:Adult; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001803:Blood Transfusion; D005260:Female; D006801:Humans; D008875:Middle Aged; D010923:Placenta Previa / Q000145:classification* / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D014463:Ultrasonography / Q000379:methods*; D014621:Vagina / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: blood transfusion; cesarean section; hemorrhage; placenta previa; vaginal ultrasound