> old world pregnancies happened left and right with little to say about it.

Yes.

> Support systems existed because the problem was pervasive. Now the problem is generally gone, and the support systems thereafter.

Meh, support for single moms or pregnant teenagers was not all that great. To large extend, they were punished and suffered, they were blamed. Their kids were oftentimes blamed.

You are better off being pregnant teenager is a single mom today then in 1950 or 1925 or whatever.