You are wildly wrong, my wife is an addiction nurse, the number of miscarriages through addiction is horrifying.
If you are talking about addiction that is one thing, and one particular population
But plenty of women who don’t smoke, drink, take drugs, still have miscarriages. The great majority of pregnant women are not substance abusers; the great majority of miscarriages do not occur because of substance abuse. Roughly 20% of recognized pregnancies end in miscarriages, more as maternal age increases.
You also mentionned too much exercise, so it really does seem that you attribute miscarriages to the mother’s actions
Not sure what point you’re trying to make.