Complex sentence: The most difficult decisions are about whether or not to resuscitate a premature baby and admit him or her to neonatal intensive care, or whether to withdraw intensive care and give the child palliative care.
Split into simpler sentences: The most difficult decisions are about whether or not to resuscitate a newborn baby or admit him or her to neonatal intensive care. And then whether or not to withdraw intensive care and give the child palliative care.