But they have got some Vampire for example.
It all depends on the Vampire's known ability and the human's ability. But normally the hybrid children don't have a mother due to the fact that they kill their mother after birth. But if it is not dealt with as soon as possible like when Edward transformed with his Bella venom into a vampire in order for her to live. Plus it has got to do with the mothers will to live and how quick the vampire is to act to keep the mother alive.