It is not true that many can survive. The baby never survives in the tube, because it ruptures if allowed to grow. Very rarely a fetus implants somewhere else in the abdominal cavity and, while risky to the mom, some do survive.
But aside from ectopic pregnancies, most "high risk" pregnancies can be dealt with in a way that preserves both the mother's and baby's life. It is not possible in every single case, but in the vast majority, it is.
And that, frankly, is a distinction without a difference. Death is death, alas.