Breasts and colostrum when pregnant
Your breasts will feel a lot fuller by third trimester, due to the combined and continued action of the hormones that are responsible for breast growth in pregnancy. The veins on the surface of your breasts become more prominent and more visible during the last third trimester and the nipples and areolae continue to darken.
Under the influence of these hormones, the internal structure of your breasts has been changing and developing ready for lactation and breastfeeding. While the placenta is still in the uterus, high levels of estrogen and progesterone block the key hormones that trigger milk secretion but you may notice from this stage onward that you are producing a clear liquid, which leaks from the nipple at all sorts of strange times, for example, when you are in the bath or making love.
This liquid is called colostrum and it is the fluid that your baby will suckle for the first few days of life, before your real milk comes through. Colostrum contains sugar, protein, and antibodies-in fact, all your baby's nutritional needs- and the most likely reason it has started to be produced now is to cater for those babies that decided to make an early appearance into this world.
Having said that, please do not worry if you do not see any colostrum throughout your entire pregnancy. I can assure you it is there, it is just that you are one of the fortunate women from whom it ha snot actually leaked out.