Well, many didn't. In prior centuries it was fairly common to have children die of any number of things... Along with quite a few mothers that died in childbirth. I think I'd be slow to just assume that modern medicine is some kind of enemy.
True, many didn’t. But not because of a few brief moments of exposure to cold. Babies born in Alaska/Siberia do not stay in hospitals until the climate changes. Al Gore’s possibly, but not the rest of us ;)
Sure, modern medicine is good...and ridiculously overboard with people running around worried about the most natural of occurrences as if they constituted the danger of the black plague.
Exposure to the elements is one of the very thing that ‘sets’ our immune system. If we live in a bubble filled with all the chemicals that ‘modern medicine’ feeds us, is it shocking that we get sick? We develop no natural resistance to anything.
And anyone thinking a walk with a newborn in fresh air, even cold air is a danger ignores the reality of the non-central heated and air conditioned world that constitutes a huge portion of this planet.