All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
If the existence of the four embryos leads to critical reprusccusions on mother's health, pose a threat over her life or abort all of her embryos, then aborting some of them is permissible to ward off some of those risks stipulated that the ages of the embryos don't exceed four months. And Allah Knows Best.