Colostrum is the very first substance your breast will produce in preparing for milk. Colostrum is a yellowish color and thick. Colostrum is so good for your baby it is full of protein and rich in immunoglobulin that help prevent infection and boot your baby immune system. In the beginning your baby will nurse just a little and this is normal on the first day.
The production of milk does not incur until three days postpartum. And for 1-2 weeks postpartum there is a transition from colostrum to milk. As the days and weeks move along you will notice some changes in milk production there is what is called the foremilk and a hindmilk.
The foremilk is much thinner and watery and the hindmilk is much richer in calories so it is important to make sure that your baby nurses until the breast is empty so that your baby is getting the nutrients of the hindmilk.
The letdown reflex occurs spontaneously when your body releases the hormone oxytocin and causes the ducts in your breast to release milk. Having the baby suck on your nipples will initiate the letdown reflex. When the nipples are stimulated oxytocin is a released and the milk is letdown. This is the same hormone that is used in labor and delivery to bring on contractions so often when you’re breast-feeding you start to feel the same contractions especially the few days following the birth.
This reflex can occur at other times such as when your hear baby cry if you hold your baby or if your breasts are stimulated during sexual intercourse or if you have an orgasm these will all bring out the letdown reflex and will cause your breasts to release milk.