Add a "life status" field in the patient form, sync-ed with the one in the pedigree.
Section: Patient information (before dob)
Display: dropdown (not radio buttons)
--unborn (displayed as "Not born yet").--
(it's unlikely that an actual patient record be created for a "patient" that is stillborn, miscarried or aborted, right ?).
Remove the "date of death unknown" field, which is to be replaced semantically by "Life status: deceased".