title: Incidence of spontaneous twin anemia-polycythemia sequence in monochorionic-diamniotic twin pregnancies: Single-center prospective study.
abstract: OBJECTIVE
  The purpose of this study was to prospectively estimate the incidence of spontaneous twin anemia-polycythemia sequence (TAPS) in monochorionic-diamniotic twin pregnancies.
  
  
  METHODS
  We prospectively examined umbilical cord hemoglobin (Hb) and reticulocyte count of consecutive monochorionic-diamniotic twin pregnancies delivered at Seirei Hamamatsu General Hospital from December 2006 to September 2013. We excluded cases of twin-twin transfusion syndrome, intrauterine fetal demise, and missing data (Hb and reticulocyte count missing from the medical record). TAPS was diagnosed using the postnatal criteria of intertwin Hb difference >8.0 g/dL and reticulocyte count ratio >1.7. Acute feto-fetal hemorrhage was defined as Hb difference >7 g/dL and reticulocyte count ratio <1.7.
  
  
  RESULTS
  A total of 185 monochorionic-diamniotic twin pregnancies were included in this study. Three fulfilled the diagnostic criteria for postnatal TAPS, and one fulfilled the diagnostic criteria for acute feto-fetal hemorrhage.
  
  
  CONCLUSIONS
  The incidence of spontaneous TAPS in monochorionic-diamniotic twin pregnancies was 1.6% (3/185) at Seirei Hamamatsu General Hospital.
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Tae
authors.initials: T
authors.lastname: Yokouchi
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Murakoshi
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mishima
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yano
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Madoka
authors.initials: M
authors.lastname: Ohashi
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shinno
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Matsushita
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Nakayama
authors.affiliation: Division of Obstetrics and Perinatology, Maternal and Perinatal Care Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Torii
mesh_terms: D000751:Anemia, Neonatal / Q000097:blood / Q000453:epidemiology*; D004200:Diseases in Twins / Q000097:blood / Q000453:epidemiology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005319:Fetal Hemoglobin / Q000032:analysis; D006769:Hospitals, General; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D011086:Polycythemia / Q000097:blood / Q000453:epidemiology*; D011247:Pregnancy; D059285:Pregnancy, Twin; D011446:Prospective Studies; D017701:Reticulocyte Count
chemical_list: D005319:Fetal Hemoglobin
keywords: acute feto-fetal hemorrhage; hemoglobin difference; monochorionic-diamniotic twin pregnancy; reticulocyte count; twin anemia-polycythemia sequence