Formula Feeding Basics for New Parents

Whether you are formula feeding from day one, supplementing breast milk, or switching after a few months, formula gives your baby the nutrition they need to grow. The basics are simple once you learn them: pick a suitable formula, mix it exactly as the label says, keep bottles clean, and follow your baby's hunger and fullness cues. This guide walks through each step.

Choosing a formula

Infant formulas sold in the United States must meet federal nutrition and safety standards, so a store brand and a name brand of the same type are both acceptable choices. Most healthy, full-term babies do well on a standard cow's milk-based formula with added iron.

• Forms. Powder is the least expensive and keeps longest. Liquid concentrate is mixed with water exactly as the label directs. Ready-to-feed costs the most but needs no mixing, which is handy for newborns and travel.
• Special formulas. Soy, partly broken down (hydrolyzed), lactose-reduced and other specialty formulas are meant for specific needs. Talk with your pediatrician before switching to one, especially if you suspect an allergy.
• Switching brands. Changing between brands of the same type is usually fine. Frequent switching while trying to fix fussiness rarely helps; bring that concern to your pediatrician instead.

Do not use formula made at home, imported formula that has not been approved for sale here, or plain cow's milk, goat's milk or plant milks for babies under 12 months. These do not have the right balance of nutrients and can make babies seriously ill.

Safe preparation

Mixing formula correctly is one of the most important things you will do for your baby.

1. Wash your hands and use a clean surface.
2. Check the expiration date on the container.
3. Read the label directions every time, especially if you change brands. Scoop sizes differ.
4. For powder, put the measured water in the bottle first, then add level, unpacked scoops of powder using the scoop that came with that can.
5. Close the bottle and shake well.

Never add extra water to stretch formula, and never add less water than directed. Too much water can lower the salt level in your baby's blood and cause seizures. Too little water can strain the kidneys and cause dehydration. Never add water to ready-to-feed formula.

What water to use

For most families, safe tap water is fine for mixing. If your home uses well water, or if you are told your local water is unsafe, use bottled water or ask your pediatrician. For babies younger than 2 months, babies born early, and babies with weak immune systems, the AAP suggests boiling the water and letting it cool before mixing. The AAP explains this in its page on how to safely prepare formula with water.

Warming and storing

• Babies can drink formula at room temperature or slightly warm. To warm it, set the bottle in a bowl of warm water. Do not use a microwave; it heats unevenly and can scald your baby's mouth.
• Test a few drops on the inside of your wrist. It should feel lukewarm, not hot.
• Throw away any formula left in the bottle within an hour after your baby starts feeding. Saliva lets germs grow.
• Mixed formula that your baby has not touched can be kept in the refrigerator for up to 24 hours.

Keeping bottles clean

Take bottles apart and wash every piece, including nipples and rings, in hot soapy water with a bottle brush, or in the dishwasher if the parts are dishwasher safe. Let them air dry fully. Sanitizing bottles often matters most for newborns under 3 months, babies born early and babies who are sick. Replace nipples that are cracked, sticky or torn.

How much and how often

Newborns usually start with small amounts and eat often, roughly every 3 to 4 hours, with feeds getting bigger over the first weeks and months. The AAP's page on formula amounts and feeding schedules gives typical ranges by age, and notes that most babies take no more than about 32 ounces in a day. In the first few weeks, if your baby sleeps longer than 4 to 5 hours, wake them to feed.

Numbers are only a guide. Follow your baby's cues:

• Hungry: rooting, sucking on hands, smacking lips, fussing. Crying is a late sign.
• Full: slowing down, turning away, closing the mouth, relaxed hands, falling asleep.

Do not push your baby to finish a bottle. Steady weight gain, about six or more wet diapers a day after the first week, and a content baby between feeds are the best signs your baby is getting enough.

Paced bottle feeding

Paced feeding lets your baby control the flow, a bit like nursing. It can help prevent overfeeding and gas.

• Hold your baby fairly upright, not lying flat.
• Keep the bottle more level so the nipple is only partly full of formula.
• Let your baby draw the nipple into their mouth.
• Every few minutes, tip the bottle down to give a short break. Burp midway and at the end.
• Never prop a bottle or put your baby to bed with one. Propping raises the risk of choking, ear infections and tooth decay.

Combining formula and breast milk

Many families use both. If you want to keep up your milk supply, it helps to nurse or pump on a regular schedule and use formula for set feeds. Do not add formula powder to breast milk unless your pediatrician tells you to. Your pediatrician or a lactation consultant can help you find a balance that works.

When to call us

Call your A thru Z Pediatrics office if:

• Your baby has fewer wet diapers than usual, a dry mouth or no tears.
• Your baby vomits forcefully, often spits up large amounts, or has blood in the stool.
• Your baby refuses feeds, seems very sleepy at feeds, or is not gaining weight.
• You notice hives, swelling or ongoing rash after feeds, or you are thinking of changing formula types.
• Your baby is under 3 months old and has a temperature of 100.4°F or higher. Call right away.

Call 911 if your baby has trouble breathing, swelling of the lips or face, turns blue, or is limp. Have questions about feeding? Request a visit.