If we can't decide on when life begins, let her kill her child after birth, as well, if it is better for her? Why not as a toddler, if it is a burden? It's not a fully-formed human, the same argument applies.

Why not default to protecting life as a default instead of murder?

Why not spend resources to help the mother with pregnancy and taking care of the child or adoption?

If there are alternatives to killing innocent life, why not pursue them instead?