The parasitic twin, also called fetus in fetu, corresponds to the presence of a fetus within another that has normal development, usually within the abdominal or retoperineal cavity. The occurrence of parasitic twin is rare, and it is estimated that it occurs in 1 in every 500 000 births.
The development of the parasitic twin can be identified even during pregnancy when an ultrasound is performed, in which two umbilical cords and only one baby can be observed, for example, or after birth, both through imaging tests and also by development of structures that are projected out of the baby's body, like arms and legs, for example.
Why does it happen?
The appearance of the parasitic twin is rare and, therefore, the reason for its appearance is not yet well established. However, there are some theories that explain the parasitic twin, such as:
- Some scientists believe that the emergence of the parasitic twin happens due to the alteration in the development or death of one fetus and the other fetus ends up encompassing its twin; Another theory says that during pregnancy, one fetus cannot form its right body, which causes his brother to "parasite" in order to survive; a final theory suggests that the parasitic twin corresponds to a highly developed cell mass, also called teratoma.
The parasitic twin can be identified even during pregnancy, but also after birth or during childhood by means of X-rays, magnetic resonance and computed tomography, for example.
What to do
After identifying the fetus in fetu , it is recommended that surgery be done to remove the parasitic twin and, thus, to prevent complications from happening to the born baby, such as malnutrition, weakening or organ damage.
