What is vanishing twin syndrome?
this is what VTS is Vanishing Twin Syndrome occurs when one of a set of twin fetuses apparently disappears from the womb during pregnancy, usually resulting in a normal singleton pregnancy.
What really happens? One of the fetuses in a twin pregnancy spontaneously aborts, usually during the first trimester; the fetal tissue is absorbed by the other twin, the placenta, or the mother, thus giving the appearance that the twin "vanished."
Uhh... isn't that where you have twins on the ultrasound but you have a miscarrage with one and keep the other?
I think that's it...