title: Twin anemia-polycythemia sequence in two monochorionic twin pairs without oligo-polyhydramnios sequence.
abstract: Placental vascular anastomoses in monochorionic twins may lead to acute or chronic inter-twin transfusion. We report an uncommon form of chronic inter-twin transfusion, referred to as twin anemia-polycythemia sequence (TAPS), with severe anemia in one twin and polycythemia in the other, without the characteristically associated twin oligo-polyhydramnios sequence (TOPS) seen in the classical twin-to-twin transfusion syndrome (TTTS). The clinical course and placental characteristics of two pairs of monochorionic twins with TAPS born at, respectively, 33 and 34 weeks' gestation were reviewed. Serial fetal ultrasound examinations revealed no signs of TOPS. At birth, both donor twins were severely anemic requiring blood transfusion and both recipients were polycythemic, one requiring partial volume exchange transfusions. Inter-twin difference in reticulocyte counts was extremely high, suggesting a chronic form of inter-twin blood transfusion. Placental injection studies revealed a preponderance of very small (<1mm) arterio-venous anastomoses in one direction. In conclusion, chronic inter-twin transfusion may lead to an uncommon form of inter-twin transfusion, named TAPS, not associated with TOPS, resulting in severe fetal or neonatal hematological complications. We hypothesize that TAPS is mediated through minuscule unidirectional anastomoses. TAPS can be diagnosed antenatally with Doppler studies and postnatally by hemoglobin and reticulocyte measurements.
authors.affiliation: Division of Neonatology, Department of Pediatrics, J6-S Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands. e.lopriore@lumc.nl
authors.forename: E
authors.initials: E
authors.lastname: Lopriore
authors.forename: J M
authors.initials: JM
authors.lastname: Middeldorp
authors.forename: D
authors.initials: D
authors.lastname: Oepkes
authors.forename: H H
authors.initials: HH
authors.lastname: Kanhai
authors.forename: F J
authors.initials: FJ
authors.lastname: Walther
authors.forename: F P H A
authors.initials: FP
authors.lastname: Vandenbussche
mesh_terms: D000328:Adult; D001034:Apgar Score; D005260:Female; D005330:Fetofetal Transfusion / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D010920:Placenta / Q000098:blood supply; D006831:Polyhydramnios / Q000175:diagnosis*; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis; D011272:Pregnancy, Multiple; D014430:Twins, Monozygotic