The fourth, fifth, and sixth months of pregnancy is the period called the second trimester. The breasts continue to enlarge but there is less nipple tenderness. A small amount of colostrum may start leaking from the breasts.
Mothers will notice the tissue just behind the nipple (nipple root) becoming stretchier and easier to grasp. This will allow the baby to latch and breastfeed effectively. The nipple root is assessed using the pinch test.
As the milk tissues grow and develop to get ready to produce milk, blood flow to the breast increases. In lighter-skinned women, this can result in the veins of the breasts becoming more prominent.
If the milk tissues are not developing (a condition called insufficient glandular tissue), the breasts do not change. There is no tenderness and no growth of the breast and in lighter-skinned women, there is no increase in the number of visible veins.