Apparently it’s the first pregnancy ending before coming to full term that causes the problems.
There are changes that begin in the breast tissue when a woman gets pregnant that are completed when she delivers at full term. When that process is interrupted, the changes are not brought to completion and that leaves the tissue susceptible to cancer growth.
If a woman has a first pregnancy come to full term, those changes are completed and subsequent interrupted pregnancies do not cause the damage that an interrupted first pregnancy does.
One thing that is VERY protective against breast cancer is breast feeding, the longer the better. That is not very widely publicized for some reason.
You’d think that with all the brouhaha about breast cancer and preventing it, they’d focus on that more. But I guess they don’t like to do or say anything that makes women who bottle fed feel bad about themselves.
Nope, it's more sinister than that. They don't want ANYTHING to come out that would threaten their vaunted 'right to choose'.