A woman has a choice between aborting or continuing a pregnancy because pregnancy is a condition of the woman's body. The choice to abort also means that a child isn't going to be born and a choice to continue means that a child is really likely to be born alive. That's all.
If you choose to continue the pregnancy to term and give birth, and the child is born alive, you don't have a choice to end that child's life because it is unrelated to your body after birth. It does not cause any particular condition of your body or, indeed, affect your body in the slightest degree any more. Because it is outside of and not attached to your body, it has its own life independent of yours.
If the woman didn't want the babies after she gave birth, she could have put them up for adoption or dropped them off at safe haven site or asked somebody else to take care of them.
The woman had been offered legal choices by society - abort or carry to term, if you carry to term, keep or give away. She chose to carry to term instead of abort - okay, that's a choice - but when she gave birth, she had two legal choices, to keep or to give away, and she chose to kill them, which is illegal - it's a choice against the law and it's not okay. She had no justification for killing them because she had a legal option to give them away.
This is thus completely different from having an abortion, especially in early pregnancy, because there is no way to give away embryos to others. Scrab is just saying that if she didn't want to keep the babies, she could have chosen not to continue her pregnancies at all, which is a legal choice because ending a pregnancy is ending a particular state of one's own body.