No, some stay the same size during and after pregnancy.
Yes, after heat cycles, a female dog's nipples usually return to their normal size and appearance. It is common for the nipples to swell and become more prominent during heat due to hormonal changes and increased blood flow to the area.
nipples vary in size, so yes they're normal.
Pregnancy will cause breast changes, they may not ever go back to "normal" or pre pregnancy size. And they will never be pre-pregnancy shape. Many people assume breastfeeding causes the breasts to sag which is completely false. It is preganancy, age, heredity and weight loss/gain.
When your breast grows & when you have nipples.
when your hormones get crazy
Yes, it is normal. There are very small openings on the nipples to allow breast milk to flow during lactation and breastfeeding. Males can also have small openings, but it is not as common to be able to actually see any of them, because of the difference in size of the nipples, being so small.
During breastfeeding, a woman's nipples may temporarily enlarge and become more prominent due to increased blood flow and stimulation. However, this change is usually temporary and they typically return to their pre-pregnancy size once breastfeeding ceases. Each woman's body may respond differently to breastfeeding, so there may be variation in how nipples change and revert back after breastfeeding.
during pregnancy
In many women pregnancy, depending on the length of the pregnancy, results in a darkening and enlargement of the nipples. Breasts usually enlarge and then return to their usual size, or smaller, or not.
A spurt in their size is a sign of puberty, after that they darken if u are pregnant, the areolas become large and Montgomery glands are visible and of course the mammary glands also inc. in size.
Breast-feeding is highly recommended. The "sucking" of the infant on the nipples alters the physiology of milk production. In this case, size doesn't matter.