the most common abnormality is downs syndrome, downs syndrome babies/children can have a good life, but they can also be affected with other health disorders, such as heart problems, as mentioned above, your aunty needs to talk to her doctors and find out why they reccomend that she aborts, there are others chromosomal problems other than downs syndrome where a baby can continue to grow but once born usually do not live very long
Make sure the doctors explain to you exactely what's going on and why they recommend you abort. They need to be clear!
What sort of abnormality? It is depends if baby can still live after birth....