Hello, I would be happy to help you with your question.
I am terribly sorry about your loss! From what you are saying, it does not sound like your wife has delivered yet. The
umbilical cord cysts are not common, but I have seen them a few times over my career. It is the only clue thus far to a problem that has resulted in the worst possible outcome. Hopefully this will prompt a thorough evaluation of the fetus after the birth, that will specifically include a
karyotype (chomosomal analysis) in order to look for an explanation for what has happened.
The fact that you recently had a normal
ultrasound was reassuring at the time, but the workup of a
fetal death is extensive and includes evaluation of the mother (e.g. looking for diabetes, blood pressure disease), evaluation of the
pregnancy and placenta (e.g. looking for an abruption or bleeding related to the placenta) and evaluation of the baby (e.g. an autopsy and karyotype).
I hope that this helps. I cannot express enough my sorrow for your situation.