No. Pregnancy itself does.
No not necessarily. My friend breastfed and her boobs are still perky. Me on the other hand lol I had a massive supply of milk so my boobs were HUGE. I guess it depends on how big your breasts grow during pregnancy and when your milk comes through
It depends on lots of things. Make sure you have a very supportive bra, and that will help, but sometimes there isn't much you can do to stop it if it will happen
I like having boobies.! Before my pregnancy they were just small lol but yea everyone is different