The way that I see sacrificing the child to save the mother is that it is no different that the same decision if the child were already born. Let’s say a mother has 5 kids, and she’s needs a heart transplant or she will certainly die. Does it make sense that she should take the heart of one of her children–let’s say the youngest, a 4 year old? Certainly no 4 year old would want to be without a mother. And she has to think of the other children. See, it just becomes ludicrous. But why is the decision any different if the child is 4 years old or 4 months old in the womb?

The ONLY exception I can think of is in the case where saving the baby may not be possible under any circumstances, such as a tubal (ectopic) pregnancy where in theory the baby absolutely cannot survive (because it is not growing in the womb, but in some other part of the body), and the mother absolutely cannot survive bringing the baby to term. Again, I’m not a doctor, so “absolutely” may be too strong a word in both cases. But assuming such a scenario exists, it would be perhaps the only rationale for abortion given that the option of saving both mother and child may not exist. Even in this case, though, there are examples of ectopic pregnancies resulting in live births (according to the wiki article). So again, we may be left without any concrete examples of such a case.

However, if the decision is kill the baby to save the mother, or save the baby at the risk of the mother’s life, even if you somehow knew with 100% certainty that the mother could not survive, it seems clear to me that you could not sacrifice the child to save her any more than you could do the same to a child already born.