title: Adverse perinatal outcome of twin pregnancies according to chorionicity: review of the literature.
abstract: Twin gestations are at significant increased risk for adverse perinatal outcome. As a result, although prospective randomized data is lacking, increased fetal surveillance has been advocated for twins. Growth concordance is considered a reassuring sign in twins and conversely, discordancy to possibly reflect a hostile intrauterine environment at least to the smaller twin. Consequently, increased surveillance of discordant twins is commonly practiced. Monochorionic twins are at further risk for type-specific perinatal complications, for example, twin-twin transfusion syndrome. Recently, precise first-trimester depiction of chorionicity has enabled early antepartum stratification of twin gestations according to chorionicity, in comparison with previous later (mid- and third-trimester) ultrasonographic diagnosis of chorionicity. This immediately leads to the question whether antenatal testing of twins should differ according to chorionicity? Review of the literature supports that despite the existence of complications unique to monochorionic twin gestations, dichorionic twins sustain an increased risk of adverse perinatal outcome (such as fetal growth restriction) in comparison with singletons, and that close antenatal fetal surveillance of twins should be performed, irrespective of chorionicity.
authors.affiliation: Department of Obstetrics & Gynecology, St Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, New York 10019, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Sherer
mesh_terms: D004200:Diseases in Twins / Q000175:diagnosis / Q000196:embryology*; D005314:Embryonic and Fetal Development; D005260:Female; D005313:Fetal Death / Q000150:complications / Q000196:embryology; D005330:Fetofetal Transfusion / Q000196:embryology; D005865:Gestational Age; D006801:Humans; D010920:Placenta / Q000473:pathology; D011247:Pregnancy; D011256:Pregnancy Outcome; D011295:Prenatal Care / Q000592:standards; D012307:Risk Factors; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal