Need advice please

Patient: I am rh negative. my doctor did not give me my rhogam shot until 34 weeks. a few days i had a placenta ebruption then 5 days later it happened again they finally decided to do a c section they said my son was born with seizures and was completely brain dead. a few days later his kidneys started working, he started breathing on his own and was moving when i touched him well without my consit the took the oxygen from his nose and later on in the middle of the night he passed away. i have had 4 other perfectly fine pregnancies. everything was fine with the last one until that day. what could have caused my placenta to ebrupt?

Doctor: