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Vanishing twin Wikipedia

DiseaseDisorder infobox |
Name = Vanishing twin |
ICD10 = |
ICD9 = 651.33 |


A vanishing twin, also called twin embolisation syndrome' or foetus papiricus, is the term for a fetus who is partially or completely reabsorbed during the pregnancy, as opposed to a normal birth or a miscarriage.

One theory for the creation of a vanishing twin is due to an atypical fertilization process. Fraternal twins usually develop by the fertilization of two ova by two sperm each of which grow in one common sac within the womb. This is called dizygotic monochorionic twins. Vanishing twin is thought to occur when two difference sacs are formed causing one, the vanishing twin, to be squished flat as it is out competed for space by the other twin.

According to some researchers, vanishing twins occur in up to one out of every eight pregnancy|pregnancies and may not even be known in most cases. In other cases, the vanished twin appears to be painted on a translucent sheath of skin delivered with the birth of the surviving baby. The twin is lifeless form with what could be described as a 'fossilized' look. This may not affect the birth of the live baby at all. However, there are other cases where the vanishing twin can create further complications in the pregnancy like slow growth of the fetus and premature deliveries. Since it hypothesized that some instances of vanishes twins leave no detectable trace, it is impossible to say for certain how frequent the phenomenon is. Logically, something that is asserted to leave no trace cannot be proven or disproven to exist.

The Vanishing Twin Syndrome has been cited by biotech company Acu-Gen as an ad hoc hypothesis to explain false results of the company's Baby Gender Mentor test. According to the company, on occasions where their pregnancy gender test has apparently given the incorrect gender of the fetus, the apparent mistake can be explained by a fetus having been present at the time of testing, but later being reabsorbed as a vanished twin.

It has been speculated that the children born in such a pregnancy may have some memories of their vanishing twins, and may feel lonely because of this. There is no scientific evidence to support this claim.

A wombtwin is a term used since 2003 to describe an embryo or fetus that was a member of a twin pair or triplet set and who died in the womb. The loss of a twin very early in pregnancy has been called "vanishing twin" phenomenon since the 1980s when twin pregnancies were made visible by means of ultrasound (sonograph) scanning. Two developing gestational sacs are seen at the first ultrasound scan but only one is visible at the second scan. The wombtwin dies owing to a poorly implanted placenta; a developmental anomaly that may cause major organs to fail or be missing completely; there may be a chromosome abnormality incompatible with life. Frequently the twin is a blighted ovum, that never developed beyond the very earliest stages of embryogenesis.

Last Modified:   2005-12-23