@FireMadeFlesh
I agree with the emotional component but 14 vs.16, biologically speaking, really doesn’t matter. People did mature more quickly way back when, out of necessity.
Once a female is of puberty, having regular reproductive cycles, the hormones she produces contribute to her being able to successfully incubate a fetus and her body is well prepared to give birth. Certainly it is not optimum but infant mortality had more to do with lack of modern medical care, sanitation, no ability to perform C-sections during a difficult or breech birth, no prenatal care, no incubators and medications for preemies, no basic medications for infant illnesses and many women died of postpartum infection regardless of their age.
Birth weight was already compromised due to lack of adequate diet for most women, lack of prenatal care/supplements and the amount of daily work they had to perform to keep their home fires burning and bread on the table. It really isn’t any different than breeding an animal of any species, a 7 month old dog can give birth and while it is harder on an animal that is not mature itself it can happen without grave outcome. Not ideal but possible as well as probable. Once the hormones kick in the body is prepped for pregnancy and delivery even if not an optimal situation.
Bottom line, nature trumps, and if it wasn’t possible for a young animal to give birth biology would not play out as it does. Disclaimer: I am not advocating teen pregnancies or breeding adolescent animals of any kind, just sayin’ it is possible or nature would readjust it’s time table.