Parents always want to know, "What should we do? Formula or breast milk?" As a pediatrician, I always recommend breast milk and breastfeeding, although that's not the right answer for every single family. What I like to recommend is happy baby, happy mother, happy mother, happy baby. I will never force a mother to breastfeed who does not want to breastfeed.
We do know that breast milk offers fantastic protection for a baby's immune system. The immunoglobulins that get transferred from the mother to the baby stay with the baby for the rest of their life. The gut is colonized initially and the baby is much less likely to get diarrheal infections, to get ear infections, much less likely to have asthma. It's protected against a lot of common illnesses in childhood. That being said, not all mothers feel breastfeeding is right for them.
You don't have to exclusively breastfeed. Some moms breastfeed during the day and they give formula at night. Some moms alternate and some moms don't breastfeed at all. And that's fine, too. The formula that is available on the market now provides a baby with all the vitamins and nutrients as comparable to human breast milk. You have to talk to your doctor - which formula would be right for your baby? We recommend babies who drink formula start with cow's milk formula. If there's something wrong - the baby's not tolerating it, the baby has severe rash or bloody diarrhea - let your doctor know and the doctor will help you choose a different formula for your baby.
Babies who are exclusively breastfed at two weeks of age should start Vitamin D drops, 400 units a day. Babies who are on formula do not need to take vitamins because all of the vitamins are supplemented in the formula.
Every family has to figure what out is right for them. Society often pressures parents to do things that they might not feel comfortable about, and that's when you need to talk to your doctor. Some moms want to only breastfeed and don't want to pump. Some moms only want to pump and don't want to breastfeed. Whatever is right for you is what you have to do for your baby, because baby will not thrive if the mom or family is not happy.