title: Selective intrauterine growth restriction in monochorionic twins: pathophysiology, diagnostic approach and management dilemmas.
abstract: Selective intrauterine growth restriction (sIUGR) in monochorionic twins is associated with a substantial increase in perinatal mortality and morbidity for both twins. Clinical evolution depends on the combination of the effects of placental insufficiency in the IUGR twin with inter-twin blood transfer through placental anastomoses. Classification of sIUGR into types according to the characteristics of umbilical artery diastolic flow in the IUGR twin permits the differentiation of clinical and prognostic groups. sIUGR type I has normal diastolic flow and relatively good outcome. Type II is defined by persistently absent/reverse end-diastolic flow and is associated with a high risk of intrauterine demise of the IUGR twin and/or very preterm delivery. Type III is defined by the presence of intermittent absent/reverse end-diastolic flow (iAREDF), and is associated with 10-20% risk of unexpected fetal demise of the smaller twin and 10-20% risk of neurological injury in the larger twin. The management strategy for sIUGR with abnormal umbilical artery Doppler (types II and III) remains a challenge, and may include elective fetal therapy or close surveillance with fetal therapy or elective delivery in the presence of severe fetal deterioration. Small clinical series reporting the use of cord occlusion or laser therapy in severe cases suggest that the outcome of the larger twin might be improved. There is probably no single optimal strategy, since decisions will ultimately be influenced by the severity of IUGR, gestational age, parents' wishes and technical issues.
authors.affiliation: Department of Maternal-Fetal Medicine (Institut Clínic de Ginecologia, Obstetrícia i Neonatologia), Hospital Clinic-IDIBAPS, University of Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBER-ER), Spain.
authors.forename: Dan V
authors.initials: DV
authors.lastname: Valsky
authors.forename: Elisenda
authors.initials: E
authors.lastname: Eixarch
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Martinez
authors.forename: Fatima
authors.initials: F
authors.lastname: Crispi
authors.forename: Eduard
authors.initials: E
authors.lastname: Gratacós
mesh_terms: D004200:Diseases in Twins / Q000503:physiopathology / Q000517:prevention & control*; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology / Q000517:prevention & control*; D046128:Fetal Therapies; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging* / Q000628:therapy; D006801:Humans; D010927:Placental Insufficiency / Q000000981:diagnostic imaging* / Q000628:therapy; D011247:Pregnancy; D012039:Regional Blood Flow; D014430:Twins, Monozygotic; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging*