Your breasts grow larger when you are pregnant. First, there is a change in the nipples. They grow darker and become more sensitive, and the areola also increase in size.
This is because the acinus, which produces breastmilk and is located at the tip of the breast duct that is the path of breastmilk, grows and develops during pregnancy in preparation for lactation after the baby is born.
The average non-pregnant breasts (left and right) weigh about 200 g in total. This increases to 400-600 g in late pregnancy and 600-800 g during the lactation period, or 3-4 times heavier than normal.
The breasts grow smaller 6-9 months after the start of breastfeeding, but it has been reported that the ability to produce breastmilk does not change even after that.