Indeed. The post referenced here mentions “that in very infrequent cases, babies and mothers may actually survive an ectopic pregnancy.” (The web link link therein seems to be dead.) The right thing to do, as we know, if to make every effort to preserve innocent life when we can.
I note with interest as well, how the author mentions instances of killing that are within the realm of moral rectitude. Also that moral choices are not a matter of self-justification in the scheme of eternal matters.
Here are links to stories about ectopic pregnancies survived by mother and child.
http://realchoice.blogspot.com/2011/05/another-baby-survives-ectopic-pregnancy.html
Haven’t found anything like a statistical analysis. In a world with 6B people, lots of weird stuff will happen. Given the way an ectopic pregnancy works, I really don’t think survival is anything to bet the farm on.