Part 1 of the introduction to the Womb Twin Survivors Research Project. Explaining what a womb twin survivor is. Womb twin survivors are the sole survivors of a twin or multiple pregnancy. Their twin died in the womb or around birth and this includes the "vanishing twin" pregnancies. Various signs are explained, first during the pregnancy, then at the birth and finally inside the body of the survivor, which includes a dermoid cyst and a teratoma.