A New Parent's Guide to Baby Formula

Formula-feeding your baby? Here's everything you need to know to start out right—from which formula to choose to how much to feed your little one. 

Baby Drinking Formula Romrodphoto/Shutterstock
With so many different brands and types baby formula at the store, it can be a bit overwhelming to figure out what's the best one to feed your baby. So how do you narrow it down?

"To start, it is helpful to understand that there [are] cow milk-based formulas, soy-based formulas and special formulas, which have different proteins if the baby has allergies," says Alison Mitzner, M.D., a board-certified pediatrician from New York. "Most babies can start on a cow milk-based formula."

If you're choosing between a major brand or a store brand, you don't have to worry that you're giving your baby something of inferior quality. Formulas are regulated by the Food & Drug Administration so they must all meet federal nutreint requirements. That means you're pretty safe in choosing any American brand for your child, says Danelle Fisher, M.D., FAAP, chair of pediatrics at Providence Saint John's Health Center in Santa Monica, California. "It may not matter as to the particular brand," Dr. Mitzner adds. "Often parents start on the formula that the hospital gives new moms or pediatrician may give at the first visit."  

Should you ever change formula?

For most babies, gassiness and fussiness are the big triggers for switching formula brands or types. "Both gas and fussiness are reasons to consider a switch to another formula," says Dr. Fisher. "It is safe to try another brand that may be made for babies with fussiness or gas, but it is important to consult your pediatrician before making more than one switch. Remember to give the baby a good three to five days on a different formula in order to assess how the baby is doing, as you may not see symptomatic improvement after one day." 

Deborah A. Sandrock, M.D., IBCLC, assistant professor of pediatrics at Drexel University College of Medicine and attending physician at St. Christopher's Hospital for Children in Philadelphia suggests that you stick with a brand once you've made a choice. "Given enough time, most babies will adjust to formula; therefore, formula should not be switched without good reason," she says.

What formulation should you pick?

Since all formula is regulated to contain the same calories and nutrients, the difference between liquid, powder and ready-to-go just boils down to convenience and price. The powdered formula that comes in a canister with a scoop is the most affordable, but needs to be mixed with the right amount of water each time. Liquid formula is concentrated so it also needs to be mixed with water. It's more expensive than the powder, but is a little easier to prepare. The ready-to-go is already premixed so it requires no special preparation: just add to a bottle and you're set to feed your baby.

How much should your baby eat?

For many parents, making sure their baby is getting enough to eat is a big concern. Fortunately, there's an easy way to monitor if your baby's getting what she needs. "Wet diapers are one of the best indicators that your baby is getting enough," says Dr. Mitzner. "With formula, also since you can quantify exactly how much your baby is getting you (and your pediatrician) will know if your baby is getting enough." 

Remember that as your baby grows, the amount of formula your baby needs will change. According to Dr. Sandrock, the amount your child should eat on average is as follows:

  • One week old: 1 to 2 ounces about every two hours
  • Two weeks old: 2 to 3 ounces every 2 to 3 hours
  • Three weeks old: 3 to 4 ounces every 3 to 4 hours
  • Four weeks old: 4 ounces every 3 to 4 hours
  • Two months old: 5 ounces every 3 to 4 hours
  • Three months old: 6 ounces every 3-4 hours

She adds that 6 ounces per bottle is usually enough for babies older than two months old, but some babies drink up to 8 ounces at a time, drinking on average 24 to 32 ounces in 24 hours.

If your baby seems to spit up a little bit—not vomit a full stomach of formula—try offering a little less in the next bottle and see if that helps. "Drinking too much can be associated with wet burps and spit ups," Dr. Sandrock says 

How do you safely prepare formula?

Since formula is the main source of food for your baby, it's important to pay attention to the mixing guidelines and food safety procedures so you can ensure your child is getting the right mix of nutrients and not opening them up for potential harm.

"Formula must be mixed properly," Dr. Sandrock says. If you're using powdered formula, she suggests adding water to the bottle first, then the powder with approximately 2 ounces of water for every scoop. Concentrated liquid formula is mixed 1:1 with water. It is recommended that the water comes to a rolling boil for about one minute—boiling for longer than that could increase the concentration of impurities. If you live in an area where tap water is safe to drink, it's safe to use to prepare your baby's formula.

"As far as temperature of the milk, it is okay to give babies the formula without warming it up, either cold or room temperature," adds Dr. Mitzner. "If you do warm it up, the simplest way is to put the bottle in a cup of hot water for a few minutes. Also, test it first on your skin to make sure it is not too hot. The formula should be lukewarm only." Dr. Mitzner warns against warming bottles in the microwave, because it heats unevenly and can put your baby at risk of scalding the mouth if it's too hot.

How to Prepare a Bottle of Formula

How long can you store a prepared bottle?

Formula may be mixed ahead of time and refrigerated for up to 24 hours, says Dr. Sandrock. "Once your baby has been drinking from a bottle of formula, it must be discarded after one hour."

What do you do when you're on the go? You can buy ready-to-go formula that requires no mixing, but it does come with a higher price tag. Alternatively, you can place clean water in your baby's bottle and store the proper amount of powder or liquid you need in another container to be mixed together at the time of feeding.

How do you choose the right bottle?

Just like formulas, there are tons of different styles and options for bottles. Most bottles aren't that different from each other, but some do claim to be easier on little tummies and gentler for fussy babies. Look for bottles made of safe, BPA-free plastic or glass or the ones with the disposable liner where you can squeeze out any extra air. "A slow flow nipple is recommended for a newborn to slow the volume of feed," says Dr. Sandrock. You can increase the flow speeds as your child gets older, but that's only a matter of preference.

Like anything else for your baby—from the formula you use to the diapers you choose—what it comes down to is what's best for you and for your baby.