title: Fetal hypertension: an insight into the pathogenesis of the twin-twin transfusion syndrome.
abstract: OBJECTIVE
  To investigate if systemic hypertension occurs in fetuses with twin-to-twin transfusion syndrome (TTTS).
  
  
  METHODS
  We conducted an observational cohort study in a tertiary care centre in 23 pregnant women with TTTS. Polyhydramnios stuck twin sequence occurred at a median gestational age of 22 weeks (range 15-27). Biventricular myocardial hypertrophy was diagnosed in 22/23 recipient fetuses. In cases with atrioventricular valve regurgitation (AVR), it was possible to estimate the fetal systolic systemic blood pressure by ultrasound, on the basis of the simplified Bernouilli equation. The diagnosis of fetal hypertension (FHT) was made when the estimated systolic arterial pressure was equal to or above 1.6-fold the expected value.
  
  
  RESULTS
  In 10 pregnancies (group A), fetal blood pressure could be assessed in recipients with AVR. The maximum velocities ranged from 2.9 to 5 m/s, leading to estimates of systemic fetal arterial pressure from 37 to 104 mmHg, that is, 1.6- to 2.8-fold the expected values. In 13 pregnancies (group B), fetal blood pressure could not be assessed in the absence of AVR. In group A, perinatal death (16/20) and hydrops (7/20) were significantly more frequent than in group B (8/26 and 1/26 respectively).
  
  
  CONCLUSIONS
  Fetal systemic hypertension may occur in recipient twins and could play a role in the pathophysiology of TTTS.
authors.affiliation: Maternité, Hôpital Necker-Enfants Malades, AP-HP and Université Paris V, Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Mahieu-Caputo
authors.forename: L J
authors.initials: LJ
authors.lastname: Salomon
authors.forename: J
authors.initials: J
authors.lastname: Le Bidois
authors.forename: L
authors.initials: L
authors.lastname: Fermont
authors.forename: A
authors.initials: A
authors.lastname: Brunhes
authors.forename: P
authors.initials: P
authors.lastname: Jouvet
authors.forename: Y
authors.initials: Y
authors.lastname: Dumez
authors.forename: M
authors.initials: M
authors.lastname: Dommergues
mesh_terms: D015331:Cohort Studies; D005260:Female; D005315:Fetal Diseases; D005330:Fetofetal Transfusion / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D005865:Gestational Age; D006325:Heart Atria / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000453:epidemiology; D011247:Pregnancy; D016216:Ultrasonography, Prenatal