I don't know if you've got kids or not but there are plenty of girls who would be beaten or worse for a pregnancy out of marriage.
Obviously we dont know the circumstances but it's entirely possible this was a young and very frightened woman who acted out of fear.
It might of course be a heartless fiend who chose to put her baby's life at risk for shots shits and giggles, in which case throw the book at her. But these incidents are usually a case of a vulnerable woman who cannot think her way out of what she perceives to be an awful situation she can't escape from.
I'd perhaps exercise a little modification of your ire.
Just for now, at least.