title: [Report of a case with twin anemia-polycythemia sequence and literature review].
abstract: OBJECTIVE
  To summarize and review the clinical characteristics including clinical features, prenatal characteristics, diagnosis, treatments and short-term outcomes of the twin anemia-polycythemia sequence (TAPS) to improve the recognition of the disease.
  
  
  METHODS
  The clinical data of one case with twin anemia-polycythemia sequence and the reports of 15 cases seen in the past 5 years were reviewed and analyzed.
  
  
  RESULTS
  There was an increasing number of reports of cases with TAPS. Prenatal manifestation: among the 16 cases, TAPS occurred in 13 cases naturally and in 3 cases occurred after laser treatment. Amniotic fluid volume showed no significant difference in 16 cases. Middle cerebral artery peak systolic velocity (MCA-PSV) > 1.5 multiples of the median (MoM) in the donor were 11/16 cases and 3/16 cases were not tested. MCA-PSV < 1.0 MoM in the recipient were seen in 10/16 cases and in 3/16 cases MCA-PSV was not tested. Hydrops fetalis was found in 6/16 cases. Intrauterine intervention: intrauterine blood transfusion was performed in 4/16 cases, fetoscopic laser occlusion of chorioangiopagus vessels was performed in 4/16 cases, umbilical cord occlusion selective feticide was done in 2/16 cases and intrauterine hemodilution in the recipient was performed in 1/16 case. Postnatal manifestation: average hemoglobin concentration in the anemic neonate was 95 g/L and in the polycythemic one was 208 g/L, intertwin Hb difference was > 80 g/L in 10/16 cases and < 80 g/L in 2/16 cases (after intrauterine laser treatment). Intertwin reticulocyte count ratio was > 1.7 in 5/16 cases and < 1.7 in 1/16 case (after intrauterine laser treatment). Postnatal treatment: 9/16 cases of donor had anemia, among them, 6/16 cases were given blood transfusions, 6/16 cases of recipient with hyperviscosity underwent partial exchange transfusions. Neurodevelopmental follow-up during neonatal period was normal in 11/16 cases, in our case, neurodevelopmental follow-up at the corrected gestational age 3 months was normal.
  
  
  CONCLUSIONS
  TAPS is a new atypical form of twin-twin transfusion syndrome (TTTS) that presents as a large intertwin hemoglobin difference with one twin developing anemia and the other developing polycythemia, without oligohydramnios-polyhydramnios sequence that is required for the diagnosis of TTTS. We suggest that routine doppler studies and MCA-PSV measurements should be performed during each follow-up visit in all uncomplicated monochorionic twin pregnancies, in order to find out the cases required intrauterine intervention to decrease neonatal mortality rates and improve the prognosis.
authors.affiliation: Department of Neonatology, Gynecology and Obstetrics Hospital, Fudan University, Shanghai, China.
authors.forename: Ji-mei
authors.initials: JM
authors.lastname: Wang
authors.forename: Guo-qiang
authors.initials: GQ
authors.lastname: Cheng
authors.forename: Bei-qian
authors.initials: BQ
authors.lastname: Qian
authors.forename: Yong-qin
authors.initials: YQ
authors.lastname: Meng
mesh_terms: D000740:Anemia / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D001783:Blood Flow Velocity; D001805:Blood Transfusion, Intrauterine; D005260:Female; D005330:Fetofetal Transfusion / Q000150:complications / Q000175:diagnosis*; D005865:Gestational Age; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D017075:Laser Coagulation; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011086:Polycythemia / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis* / Q000628:therapy; D011379:Prognosis; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal
chemical_list: D006454:Hemoglobins