Typically, if you leak breast milk, it is no more than a few drops at the time. It might be yellowish in color, like butter milk, and it's going to be very thick. Some women start leaking colostrum as early as the first trimester of pregnancy, but leaking breasts are mostly a third trimester symptom. If you are leaking substantial amounts of milk, you can try using breast pads to keep your clothes from getting wet. Colostrum is your first milk, and it contains everything your baby needs in the first few days of life. It contains a myriad of antibodies that serve to protect your baby from infections and diseases, and colostrum also has more proteins and fat than the breastmilk you will start producing some time after birth. Colostrum is the perfect way to deliver many nutrients to your baby in a small concentration, given the fact that the digestive system is still imperfect and the stomach tiny. For more about breast changes in pregnancy, see sore and tender breasts.