I see no reason why they cannot give birth and if they do not want the child, give him/her for adoption...
There are many couples who, for some reason, want, but cannot have a child...And there doesn’t seem to be a lot of young ones for adoption anymore...They are being killed off before birth...
However, adoption can be as difficult for the birthmother as abortion. It is physically more demanding, and it can leave a bigger attachment-wound when she has to part with her little one, even if she didn't "want" the little one to begin with.
Adoption would be the ONLY right and just solution if she and the child's father cannot properly parent their child, but most men AND women will be no better than they *have* to be --- even if it involves complicity in murder.