title: Placental pathophysiology of the twin oligohydramnios-polyhydramnios sequence and the twin-twin transfusion syndrome.
abstract: Currently accepted sonographic criteria for antenatal diagnosis of twin-twin transfusion (TTT) syndrome include a monochorionic placenta with same-sex twins, marked growth discordance, and oligohydramnios of the growth-retarded twin with coexistent polyhydramnios of the larger twin. Our previous report of nine women fulfilling these criteria, examined using sequential funipuncture of both fetuses, demonstrated inter-twin blood transfusion in only four cases (44 per cent). It was proposed that traditional sonographic criteria actually describe a heterogeneous group of disorders more appropriately described as the twin oligohydramnios-polydramnios sequence (TOPS). True TTT is a subset of this population, the antenatal diagnosis of which requires specific demonstration of transfusion from one fetus (donor) to the other (recipient). In this report, antenatal placental evaluation has been correlated using duplex pulsed-wave Doppler analysis of arterial blood flow velocity with postpartum gross and histopathologic evaluation of the placenta, with special attention to microvasculature. There was a higher incidence of resistance to blood flow, abnormal umbilical cord insertion, and diminished placental microvasculature associated with oligohydramnic growth-retarded (donor) twins when compared with polyhydramnic (recipient) twins. Based on these observations, it is proposed that TTT and TOPS represent asymmetric placental insufficiency resulting from aberrant placentation.
authors.affiliation: Department of Obstetrics and Gynaecology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2529, USA. joe.bruner@mcmail.vanderbilt.edu
authors.forename: J P
authors.initials: JP
authors.lastname: Bruner
authors.forename: T L
authors.initials: TL
authors.lastname: Anderson
authors.forename: R L
authors.initials: RL
authors.lastname: Rosemond
mesh_terms: D001783:Blood Flow Velocity; D005314:Embryonic and Fetal Development; D005260:Female; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging* / Q000473:pathology*; D005865:Gestational Age; D006801:Humans; D016104:Oligohydramnios / Q000000981:diagnostic imaging*; D010920:Placenta / Q000473:pathology*; D006831:Polyhydramnios / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018616:Ultrasonography, Doppler, Duplex; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging