How much milk do babies need?

Many mothers wonder how much expressed breastmilk they need to have available if they are away from baby.

In exclusively breastfed babies, milk intake increases quickly during the first few weeks of life, then stays about the same between one and six months (though it likely increases short term during growth spurts). Current breastfeeding research does not indicate that breastmilk intake changes with baby’s age or weight between one and six months. After six months, breastmilk intake will continue at this same level until — sometime after six months, depending in baby’s intake from other foods — baby’s milk intake begins to decrease gradually (see below).

The research tells us that exclusively breastfed babies take in an average of 25 oz (750 mL) per day between the ages of 1 month and 6 months. Different babies take in different amounts of milk; a typical range of milk intakes is 19-30 oz per day (570-900 mL per day).

We can use this information to estimate the average amount of milk baby will need at a feeding:

  • Estimate the number of times that baby nurses per day (24 hours).
  • Then divide 25 oz by the number of nursings.
  • This gives you a “ballpark” figure for the amount of expressed milk your exclusively breastfed baby will need at one feeding.

Example: If baby usually nurses around 8 times per day, you can guess that baby might need around 3 ounces per feeding when mom is away. (25/8=3.1).

Infant’s Maximum Stomach Capacity

Per feeding

  • Day one: 5-7 mL/ 1/2 Tbs
  • Day Three: 22-27 mL/ .75-1oz
  • One Week: 45-60 mL/ 1.5-2 oz
  • One Month: 80-150 mL/ 2.5-5 oz

If your baby is taking substantially more than the average amounts, consider the possibility that baby is being given too much milk while you are away. Things that can contribute to overfeeding include:

  • Fast flow bottles. Always use the lowest flow bottle nipple that baby will tolerate.
  • Using bottle feeding as the primary way to comfort baby. Some well-meaning caregivers feed baby the bottle every time he makes a sound. Use the calculator above to estimate the amount of milk that baby needs, and start with that amount. If baby still seems to be hungry, have your caregiver first check to see whether baby will settle with walking, rocking, holding, etc. before offering another ounce or two.
  • Baby’s need to suck. Babies have a very strong need to suck, and the need may be greater while mom is away (sucking is comforting to baby). A baby can control the flow of milk at the breast and will get minimal milk when he mainly needs to suck. When drinking from a bottle, baby gets a larger constant flow of milk as long as he is sucking. If baby is taking large amounts of expressed milk while you are away, you might consider encouraging baby to suck fingers or thumb, or consider using a pacifier for the times when mom is not available, to give baby something besides the bottle to satisfy his sucking needs.

If baby is taking significantly less expressed milk than the average, it could be that baby is reverse-cycling, where baby takes just enough milk to “take the edge off” his hunger, then waits for mom to return to get the bulk of his calories. Baby will typically nurse more often and/or longer than usual once mom returns. Some mothers encourage reverse cycling so they won’t need to pump as much milk. Reverse cycling is common for breastfed babies, especially those just starting out with the bottle.

If your baby is reverse cycling, here are a few tips:

  • Be patient. Try not to stress about it. Consider it a compliment – baby prefers you!
  • Use small amounts of expressed milk per bottle so there is less waste.
  • If you’re worrying that baby can’t go that long without more milk, keep in mind that some babies sleep through the night for 8 hours or so without mom needing to worry that baby is not eating during that time period. Keep an eye on wet diapers and weight gain to assure yourself that baby is getting enough milk.
  • Ensure that baby has ample chance to nurse when you’re together.

What is normal when it comes to pumping output and changes in pumping output?

Most moms who are nursing full-time are able to pump around 1/2 to 2 ounces total (for both breasts) per pumping session. Moms who pump more milk per session may have an oversupply of milk, or may respond better than average to the pump, or may have been able to increase pump output with practice. Many moms think that they should be able to pump 4-8 ounces per pumping session, but even 4 ounces is an unusually large pumping output.

It is quite normal to need to pump 2-3 times to get enough milk for one feeding for baby (remember that the pump cannot get as much milk as a baby who nurses effectively).

Many moms are able to pump more milk per session when they are separated from baby. Milk pumped when you are nursing full-time is “extra” milk — over and beyond what baby needs. Don’t get discouraged if you are trying to build up a freezer stash when nursing full time and don’t get much milk per pumping session — this is perfectly normal and expected.

It is very common to have more milk than baby needs in the early weeks, which regulates down to baby’s needs over the first few weeks or months. When your milk supply regulates (this change may occur either gradually or rather suddenly), it is normal for pumping output to decrease. For moms who have oversupply, this change often occurs later (6-9+ months postpartum rather than 6-12 weeks).

It is normal for pumping output to vary from session to session and day to day. Having an occasional low volume day is not unusual.

During a growth spurt, don’t be surprised if baby drinks more expressed milk than usual, making it harder for mom to provide enough expressed milk. Growth spurts are temporary – try increasing nursing and adding a pumping session or two at home until the growth spurt is over.

Menstruation or ovulation can result in a temporary drop in milk supply. You might also notice cyclical dips in milk supply before your period returns, as your body begins the return to fertility. Hormonal changes also cause milk supply to decrease during pregnancy.

Remember that the amount of milk that you pump is not a measure of your milk supply!

What can cause a decrease in pumping output?

First, consider the possibility that baby is being overfed when you’re apart. If this is the case, you may actually not need to be expressing as much milk as is being requested. This is certainly not always the case, but it is not at all uncommon. See How much expressed milk will my baby need? for additional information.

When you do need to pump more milk, the first thing to check is your pump:

  • Are you using an appropriate pump for the amount of pumping that you do?
  • How old is your pump? If you have an older electric pump (particularly older than a year), or if you are pumping more often than the pump was designed for, the motor may be wearing out.
  • Many times a decrease in pumping output is because pump parts need to be replaced. Have you checked your pump and replaced any parts that are worn or that haven’t been replaced in the last 3-6 months?
  • Do you have a type of pump (like the Avent Isis) that benefits from occasionally boiling the boilable parts?
  • Switching to a larger pump flange makes a difference in pumping comfort and/or output for some moms. See Choosing a Correctly-Fitted Breastshield for more information.

Supply-demand cycle:

  • Have you reduced the number of pumping or nursing sessions recently, or cut back on nursing/pumping in other ways? Milk production is a demand-supply process. More nursing/pumping results in a greater milk supply. If you consistently decrease nursing or pumping for several days, your overall milk supply will decrease and you can expect to see a decrease in pumped amounts.
  • Has baby started solids recently? As baby eats more solids and takes in less milk, overall milk supply naturally decreases and you may see a decrease in pumping output. You may not notice a change in nursing pattern, as some babies nurse just as often, but take in less milk during those sessions. If baby started solids early (before around 6 months) or is eating lots of solids early on, you are more likely to notice a drop in supply. A very gradual start to solids around 6 months or later is less likely to affect milk supply.

Hormonal causes of decreased milk supply:

  • Have you started hormonal birth control recently? Hormonal birth control, particularly that containing estrogen, can significantly decrease milk supply.
  • Are you expecting either ovulation or your period soon, or has it recently started?
  • Are you pregnant?

Taking care of mom:

  • Have you started a strict diet? Are you getting enough calories? Snacking during the day on healthy, protein-rich foods may be helpful.
  • Are you drinking to thirst? Some moms, particularly when they are at work, will get busy and forget to drink enough fluids.
  • Are you getting enough rest? This can be hard to do when you have a baby. Try to go to bed a little earlier and to take a nap each day on your days off. Consider co-sleeping so you can get more sleep. Just a little added rest may make a big difference.
  • Have you been under an unusually large amount of stress? Stress can affect let-down and pumping output.
  • Have you been sick? Illness, especially if you have a fever, mastitis or get dehydrated, can result in a temporary decrease in milk supply. Some medications can also decrease milk supply (hormonal birth control, pseudoephedrine, ethanol/alcoholic beverages, bromocriptine, ergotamine, cabergoline).

Resources

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