Agree with the above, the lactation specialist told me not to try pumping before birth. It can cause you complications later, especially if it's your first. Plus it's SO MUCH easier after baby comes; your body knows. I started pumping 4 days after birth.
Best not to pump until a week after birth. The pre milk and colostrum are really important for a new born and unless for any reason u anticipate not being around or available that firatvweek its better for u and baby to get it fresh
You will start producing colostrum immediately after labor. Its best to get baby nursing within the first hour of birth to get skin to skin bonding time going and get milk production flowing. It takes about 3-4 days for your milk to start flowing. It also helps if You're pumping on a strict schedule. That'll help your milk come in faster.
Dont start pumping till after you are around 37 weeks as bubs is not classed as full team and by using a pump you could also bring on preteam laber
Your full supply usually won't come in until a few days after birth. But its different for most. Some get their milk earlier. Your baby will be fine feeding on the colostrum until your supply comes in.
Breast milk does start being produced until about 3 days after baby is born.