Pregnancy Complications (VSD, SUA)

Hi. My wife is pregnant with her first child. I'm 22, she's 20, she's now in
her 30th week and the 21st wk ultrasound found that she has a single
umbilical artery (SUA) and so we were told to get a foetal echocardiography.
This was performed yesterday and the foetus was discovered to have 2 to 3
Ventricular Septal Defects (VSD) of "small-to-moderate" size:

to quote the relevant bit of his report:
"Normal right and left ventricular size and function, 2-3 muscular VSDs - A
3mm apical, 2mm mid-muscular and possibly another 1mm mid-high muscular VSD.
6MMHG shunt is seen (no PS)."
the rest of his report reports everything's fine.

The doctor said that this may be a sign of one of the "syndromes".

The 21st week ultrasound revealed no other defects or deformities, so we
want to know what the chances of the child being born being with a syndrome
is, given these factors? Is the doctor right? Should we worry?

Does anyone know the chances of this number (2-3) of defects of these sizes
at this "age" closing spontaneously either before or after birth?

(We won't do an "amniocentesis" because of the small chance of
miscarriage and because we wouldn't consider an abortion whatever the
circumstances.)

thanks,
Ash.

PS. We're going to have another foetal echocardiography in 3 weeks so the
doctor can check if the defects are closing, or worse.

PPS. One other point, which the doctor says is unrelated, is that my wife
has
thrombocytopenia (a very low PLT count - her's is about 45k).