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A review of the mechanisms and evidence for typical and atypical twinning
journal contribution
posted on 2016-02-01, 00:00 authored by Helen C McNamara, Stefan C Kane, Jeffrey CraigJeffrey Craig, Roger V Short, Mark P UmstadThe mechanisms responsible for twinning and disorders of twin gestations have been the subject of considerable interest by physicians and scientists, and cases of atypical twinning have called for a reexamination of the fundamental theories invoked to explain twin gestations. This article presents a review of the literature focusing on twinning and atypical twinning with an emphasis on the phenomena of chimeric twins, phenotypically discordant monozygotic twins, mirror-image twins, polar body twins, complete hydatidiform mole with a coexistent twin, vanishing twins, fetus papyraceus, fetus in fetu, superfetation, and superfecundation. The traditional models attributing monozygotic twinning to a fission event, and more recent models describing monozygotic twinning as a fusion event, are critically reviewed. Ethical restrictions on scientific experimentation with human embryos and the rarity of cases of atypical twinning have limited opportunities to elucidate the exact mechanisms by which these phenomena occur. Refinements in the modeling of early embryonic development in twin pregnancies may have significant clinical implications. The article includes a series of figures to illustrate the phenomena described.
History
Journal
American journal of obstetrics and gynecologyVolume
214Issue
2Pagination
172 - 191Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
eISSN
1097-6868Language
engPublication classification
C1 Refereed article in a scholarly journalCopyright notice
2016, ElsevierUsage metrics
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No categories selectedKeywords
assisted reproductive technologieschimeric twinscomplete hydatidiform mole with coexistent twindizygoticfetus in fetufetus papyraceusmirror-image twinsmonozygoticphenotypically discordant monozygotic twinspolar body twinssuperfecundationsuperfetationtwinsvanishing twinAmnionChorionEmbryonic DevelopmentFemaleFetusHumansHydatidiform MoleMorulaPregnancyPregnancy ComplicationsPregnancy, TwinReproductive Techniques, AssistedTwins, DizygoticTwins, MonozygoticUterine Neoplasms
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