title: Acute twin-twin transfusion syndrome in labor: pathophysiology and associated factors.
abstract: OBJECTIVE
  To review reported cases of acute twin-twin transfusion syndrome (TTTS) in monochorionic twin pregnancies to help define variants of disease and determine associated factors.
  
  
  METHODS
  PubMed literature review using the search terms, "acute" and "twin transfusion." Articles were reviewed for clinical factors. Reference lists were carefully assessed for any additional articles. In order to rule out sudden progression of chronic TTTS as the cause, gestational age ≥31 weeks was chosen. Cases were classified into subsets of acute TTTS.
  
  
  RESULTS
  There were 150 publications from 1942-2010. There were 51 cases that were classified into four variants of acute TTTS. Four cases were difficult to classify, with hemoglobin levels that were high normal and low normal, high normal and anemic, or low normal and polycythemic. Three publications defined the incidence for acute perinatal TTTS of 1.8-5.5% of monochorionic twins. Common factors associated with acute perinatal TTTS included monochorionicity and labor.
  
  
  CONCLUSIONS
  Monochorionicity and labor are common factors underlying the propensity to acute perinatal TTTS. A spectrum of severity is for acute TTTS was seen. Perinatal specialists and neonatologists should be aware of the possibility of acute TTTS during labor, so rapid volume replacement can be performed for neonatal resuscitation.
authors.affiliation: Obstetrics and Gynecology, Weill Cornell Medical College/New York Hospital Queens, Flushing, NY 11355, USA. dwskupsk@med.cornell.edu
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Skupski
authors.forename: George
authors.initials: G
authors.lastname: Sylvestre
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Di Renzo
authors.forename: Amos
authors.initials: A
authors.lastname: Grunebaum
mesh_terms: D000208:Acute Disease; D005260:Female; D005330:Fetofetal Transfusion / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D007744:Obstetric Labor Complications / Q000209:etiology / Q000503:physiopathology*; D011247:Pregnancy; D012307:Risk Factors; D012720:Severity of Illness Index; D014430:Twins, Monozygotic