Breastmilk production begins anywhere from 1-5days after birth. The placenta detaching is what signals milk production.

Colostrum starts being produced between 16-21 weeks. It will stay colostrum until about 3-5 days after your baby is born and it will mature into the white milk you’re used to thinking and hearing of. The colostrum is full of nutrients for a newborn and will fill their tummy jus right until the milk comes in

After birth.

Your actual milk won’t come in, until after you give birth.