Mother Catches Cold For Nearly 15 Days..along With Cough..has Been

Mother catches cold for nearly 15 days..along with cough..has been under treatment with cough syrup......after 12 or 13 days mom suddenly gets fever 100 degrees.....treated with dolo 650.....
..doctor says baby could get breathlessness if fever rises.....suddenly movement stops....after a scan doctor confirms death of the baby in the womb......what could be the reason