Subject: Erythroblastosis Fetalis: communication between mother's and fetal blood

1) In erythroblastosis for the mother's Rh- blood to receive RBCs from 
fetus Rh+ blood, there should be a communication thru the placenta i.e. 
thru the villi of the fetus projecting into the intervillous spaces in the 
placenta. There would be a flow of mother's blood cells into the fetal 
circulation also. Please confirm this!!

2) Why does the first baby have less chances to develop the disease than 
the subsequent children. The mother takes about 3 months to develop a good 
titer of antibodies; therefore if the communication occurs in the early 
2nd trimester the first baby should also have lot of chances to develop 
erythroblastosis fetalis! Is this early communication possible? Comment 
and please clear it

3) Only Ig-G antibodies can cross the placenta, this means that the Rh 
antibodies prepared by the mother are Ig-G. Confirm

Re: Erythroblastosis Fetalis: communication between mother's and fetal blood