A reader asks:

Is it ok to use the same formula, but ready-made for some feedings and powder for others? Or if you use the powder should you stick with the powder?

That’s a common question.  Generally speaking, I like parents to stick to one type of formula for at least the first month of life.  Since most newborn nurseries provide ready-to-feed formulas for their bottle-fed babies, it makes sense to stick with the same formula if the baby is happy.  After a month of adjusting to formula at increasing volumes, most young infants can be switched to most other brands or types of formulas without noticing any significant changes with stooling, spitting up, gas, or other signals that determine their tolerance of the formula.  Other reasons why you might want to change formulas after one month of age:

  • Some parents prefer one brand over another, usually based on prior experience with that formula.  Most hospital nurseries and pediatricians subscribe to a “flavor-of-the-month” policy, where brand changes are regularly scheduled.  My suggestion is that if parents have a preference of one brand over another, let the nursery staff know as soon as possible so that brand can be provided.
  • The pre-filled 2 ounce bottles used in hospitals are good for the first week or so.  After that, your baby will probably need more than 2 ounces per feeding.  Buying a larger container of the ready-to-feed formula will then be more practical.
  • By 3-4 weeks of age, most babies are taking 3-4 ounces every 3-4 hours.  At this point, due to the volume of formula that needs to be prepared daily, it makes sense to make the switch to powder.  Anyway, powdered formula is lighter to carry from the car to the kitchen!
  • Most families of newborns receive coupons and even samples of formula, and these can significantly lower the overall cost of bottle-feeding.  Formula is expensive, so I encourage families to use these cost-savers.


Most full-term, healthy babies will do fine on any formula they start with.  In addition, most will be able to handle a change in brand or type after one month of age without any problems.  They might even handle that change sooner, but I don’t like to rock the boat in the first month of life if things are going well (and they usually do)!  To answer our reader’s question:  After one month of age, it really shouldn’t matter whether ready-to-feed or powdered formulas are used.  You can choose either or use both.  Over time, you will probably stick to one.

Finally, there are lots of different formulas for different issues babies may face:  prematurity, reflux (GERD), colic, gas, eczema, milk-protein intolerance, milk allergy, and more.  If breastfeeding is not an option, your pediatrician will work with you to make sure your baby is on the right formula.