The argument that abortion is ok if the fetus does not feel the pain is flawed.Infliction of pain is complete the moment one who inflicts pain on the inflicted.It need not be supported by the feeling of pain by the afflicted.
If the argument that feeling of pain is to be confirmed then Hitler’s genocide of millions can be justified on the ground that cyclon B did not cause pain and disposed of people (scientists assert).
Mere intention to cause pain to others is a sin, assert Hindu scriptures.
We may not be able to help others for it depends on factors excluding us.
But avoiding hurting others is fully under our control.
Following this principle is the greatest of all Virtues.