A vanishing twin, also known as twin resorption, is a
fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...
in a multigestation pregnancy that dies ''
in utero
''In Utero'' is the third and final studio album by American rock band Nirvana. It was released on September 21, 1993, by DGC Records. After breaking into the mainstream with their second album, ''Nevermind'' (1991), Nirvana hired Steve Albin ...
''and is then partially or completely
reabsorbed. In some instances, the dead twin is compressed into a flattened, parchment-like state known as ''fetus papyraceus''.
Vanishing twins occur in up to one of every eight multifetus pregnancies and may not even be known in most cases.
"High resorption rates, which cannot be explained on the basis of the expected abortion rate, suggest intense fetal competition for space, nutrition, or other factors during early gestation, with frequent loss or resorption of the other twin(s)."
In pregnancies achieved by
''in vitro'' fertilization, "it frequently happens that more than one amniotic sac can be seen in early pregnancy, whereas a few weeks later there is only one to be seen and the other has 'vanished'".
See also
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Chimera (genetics)
A genetic chimerism or chimera ( ) is a single organism composed of cells with more than one distinct genotype. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood ...
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Mosaicism
Mosaicism or genetic mosaicism is a condition in multicellular organisms in which a single organism possesses more than one genetic line as the result of genetic mutation. This means that various genetic lines resulted from a single fertilized ...
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Parasitic twin
A parasitic twin, also known as an asymmetrical or unequal conjoined twin, is the result of the processes that also produce vanishing twins and conjoined twins, and may represent a continuum between the two. Parasitic twins occur when a twin embry ...
References
Further reading
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External links
Vanishing twin at eMedicine.com50 articles about vanishing twin phenomenon in PubMed
{{Medical-stub
Twin
Pregnancy with abortive outcome