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1 oz an hr rule

Posted by on Oct. 24, 2012 at 10:25 AM
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I just want to ask, who came up with this rule and what fact is it even based on? This 'rule' was advice given to me on this site and the worst, and most regrettable thing i have ever done to my child. It might work for some babies but not all. I work full time, and we followed this 'rule' for about a month and a half. In that time, dd stopped sleeping through the night and woke up 8-9 times in the middle of the night to bf. Not okay or healthy. She also became incredibly fussy and cried and screamed all day. I mean, who could blame her, she was starving. She also started losing weight. After we stopped this and i let her father feed her pumped bm on demand ,and as much as she needed, she went back to normal. Thank god. I now feel the need to warn mothers you shouldn't listen to all coocoo babble you hear or read on the internet.
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by on Oct. 24, 2012 at 10:25 AM
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by Bronze Member on Oct. 24, 2012 at 10:27 AM

I don't think I've heard this one before, what's the 1 oz an hour rule?

by Gold Member on Oct. 24, 2012 at 10:30 AM
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It's based on the average milk intake. You have to be feeding on demand when home.

by Gold Member on Oct. 24, 2012 at 10:31 AM
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How much expressed milk will my baby need?

October 28, 2011. Posted in: Pumping issues

By Kelly Bonyata, BS, IBCLC

Image credit: Jerry Bunkers on flickr

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).

Here’s a calculator so you don’t need to do the math…

Milk Calculator
(for the exclusively breastfed baby)

Average number of feedings per day

Average per feeding, ounces Average per feeding, mL
Low range, ounces Low range, mL
High range, ounces High range, mL


  1. Babies younger than one month old and babies who are more established on solid foods are expected to have a lower daily milk intake.
  2. This calculator is based upon an average daily intake of 25 ounces, with a range of 19-30 ounces per day. Equivalent in mL is an average daily intake of 750 mL, with a range of 570-900 mL per day.


What if baby is eating solid foods?

Sometime between six months and a year (as solids are introduced and slowly increased) baby’s milk intake may begin to decrease, but breastmilk should provide the majority of baby’s nutrition through the first year. Because of the great variability in the amount of solids that babies take during the second six months, the amount of milk will vary, too. One study found average breastmilk intake to be 30 oz per day (875 ml/day; 93% of total intake) at 7 months and 19 oz (550 ml/day; 50% of total energy intake) at 11-16 months.

Several studies have measured breastmilk intake for babies between 12 and 24 months and found typical amounts to be 14-19 oz per day (400-550 mL per day). Studies looking at breastmilk intake between 24 and 36 months have found typical amounts to be 10-12 oz per day (300-360 mL per day).

Is baby drinking too much or too little expressed milk?

Keep in mind that the amount of milk that baby takes at a particular feeding will vary, just as the amount of food and drink that an adult takes throughout the day will vary. Baby will probably not drink the same amount of milk at each feeding. Watch baby’s cues instead of simply encouraging baby to finish the bottle.

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, after trying these suggestions, you’re still having a hard time pumping enough milk, see I’m not pumping enough milk. What can I do?

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.

Other ways of estimating milk intake

There are various ways of estimating the amount of milk intake related to the weight of the baby and the age of the baby, based upon formula intakeresearch has shown that after the early weeks these methods overestimate the amount of milk that baby actually needs. These are the estimates that we used for breastfed babies for years, with the caveat that most breastfed babies don’t take as much expressed milk as estimated by these methods. Current research tells us that breastmilk intake is quite constant after the first month and does not appreciably increase with age or weight, so the current findings are validating what moms and lactation counselors have observed all along.

The Milk Calculator from the The Adoptive Breastfeeding Resource Website does this type of estimation.



Onyango, Adelheid W., Receveur, Olivier and Esrey, Steven A. PDF The contribution of breast milk to toddler diets in western Kenya. Bull World Health Organ, 2002, vol.80 no.4. ISSN 0042-9686.

Salazar G, Vio F, Garcia C, Aguirre E, Coward WA. Energy requirements in Chilean infants. Arch Dis Child Fetal Neonatal Ed. 2000 Sep;83(2):F120-3.

Kent JC, Mitoulas L, Cox DB, Owens RA, Hartmann PE. Breast volume and milk production during extended lactation in women. Exp Physiol. 1999 Mar;84(2):435-47.

Persson V, Greiner T, Islam S, and Gebre-Medhin M. The Helen Keller international food-frequency method underestimates vitamin A intake where sustained breastfeeding is common. Food and Nutrition Bulletin, vol.19 no.4. Tokyo, Japan: United Nations University Press, 1998.

Cox DB, Owens RA, Hartmann PE. Blood and milk prolactin and the rate of milk synthesis in women. Exp Physiol. 1996 Nov;81(6):1007-20.

Dewey KG, Heinig MJ, Nommsen LA, Lonnerdal B. Maternal versus infant factors related to breast milk intake and residual milk volume: the DARLING study. Pediatrics. 1991 Jun;87(6):829-37.

Neville MC, et al. Studies in human lactation: milk volumes in lactating women during the onset of lactation and full lactation. Am J Clin Nutr. 1988 Dec;48(6):1375-86.

Dewey KG, Finley DA, Lonnerdal B. Breast milk volume and composition during late lactation (7-20 months). J Pediatr Gastroenterol Nutr. 1984 Nov;3(5):713-20.

Butte NF, Garza C, Smith EO, Nichols BL. Human milk intake and growth in exclusively breast-fed infants. J Pediatr. 1984 Feb;104(2):187-95.

Dewey KG, Lonnerdal B. Milk and nutrient intake of breast-fed infants from 1 to 6 months: relation to growth and fatness. J Pediatr Gastroenterol Nutr. 1983;2(3):497-506.

Brown K, Black R, Robertson A, Akhtar N, Ahmed G, Becker S. Clinical and field studies of human lactation: methodological considerations. Am J Clin Nutr 1982;35:745-56.

Jelliffe D, Jelliffe E. The volume and composition of human milk in poorly nourished communities: a review. Am J Clin Nutr 1978;31:492-515.

Summary of Research Data
Baby’s Age Average Milk Intake per 24 hours Reference
g ml oz
5 days 498 129 g 483 ml 16 oz Neville 1988
1 mo 728 g 706 ml 24 oz Salazar 2000
1 mo 673 ml 23 oz Dewey 1983
1 mo 708 54.7 g 687 ml 23 oz Cox 1996
1-6 mo 453.6201 g per breast 440 ml x2 = 880 ml 30 oz Kent 1999
3 mo 818 g 793 ml 27 oz Dewey 1991
3-5 mo 753 89 g 730 ml 25 oz Neville 1988
6 mo 896 ml 30 oz Dewey 1983
6 mo 742 79.4 g 720 ml 24 oz Cox 1996
7 mo 875 ml (93% of total energy intake) 30 oz Dewey 1984
11-16 mo 550 ml (50% of total energy intake) 19 oz Dewey 1984
11-16 mo 502 34 g 487 ml (32% of total energy intake) 16.5 oz Onyango 2002
12-17 mo 563 g 546 ml 18 oz Brown 1982
12-23 mo 548 g 532 ml 18 oz Persson 1998
15 mo 208.056.7 g per breast 202 ml x2 = 404 ml 14 oz Kent 1999
18-23 mo 501 g 486 ml 16 oz Brown 1982
>24 mo 368 g 357 ml 12 oz Brown 1982
24-36 mo 312 g 303 ml 10 oz Persson 1998
Specific Gravity of Mature Human Milk = 1.031, so Density of Mature Human Milk ~ 1.031 g/ml;1 oz = 29.6 ml;Numbers in gray were derived using the above conversion factors.
by Gold Member on Oct. 24, 2012 at 10:32 AM
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One of the frequently asked questions of breastfeeding is “How much milk should I leave my baby while we are separated?”

The answers that I’ve seen vary. The answer that I subscribe to is “The One Ounce Per Hour Rule”.  (Which could be better described as the 1-1.25oz/hour rule).

The one ounce per hour rule is based on the average daily requirements of a breastfed infant who will take in 25oz/day of milk. (This does not vary much between one and six months). While amounts might be more or less during exclusive pumping / bottle feeding, the “One Ounce Per Hour” rule is considered the standard for shorter periods of mother and infant separation.

This method is the “breastfeeding friendly” method that is most likely to lead to longer term breastfeeding success. Other methods that allow on-demand feeding from bottles or that follow amount guidelines for formula fed babies often lead to supply decrease and early weaning or supplementation of non-human milk.

I’ve heard a lot of moms say that they are anxious about the one-ounce-per-hour rule of feeding a breastfed infant while separated from mom. I understand it. I was anxious as a new mom, too, and wanted to leave MORE than my baby needed because it hurt to leave him and I wanted to make sure he would be happy and satisfied while I was away.

The thing is.. It’s not starving your baby and it’s not letting your baby go hungry. It’s something your baby is already used to. The supply in your breasts is not static. It goes up and down across the day. Your baby is already used to this.

Your baby eats the same amount each day between one month and when solids are introduced. (A bit more during growth spurts- but this should happen at mom’s breast, since her supply has to scale.) This amount for breastfed babies averages out to 25oz/day with some babies eating as little as 19oz/day. Your supply is not static across the day, it increases and decreases across the day, so baby learns to nurse more during high supply hours, and less during low supply hours (which are typically in the evening)

What the one ounce per hour rule does is it encourages baby to view the bottle feeds as “low supply”, and mom-feeds as “high supply” and baby nurses more with mom and less with the bottle. Baby’s needs are met, not exceeded. More than one ounce per hour means baby finds bottle = high supply, breast = low supply, and starts fussing for more bottle, less mom. This means mom is stuck pumping HUGE amounts of milk.

This causes problems because the pump is ineffective. It’s like trying to siphon water out of a well with a drinking straw. It’s tedious, it’s boring, it’s a pain in the butt. Mom’s breasts let down easily to an eager baby, and noooot so well to a pump. 1-2oz per pumping session is actually EXCELLENT output. If baby is downing 2oz/hour or more than one ounce/hour? Mom would have to pump constantly at work to make up for it.

Better to convince baby that the bottle has a rotten supply and that it’s easier to gorge off mom. Easier on mom, easy enough on baby, and baby’s needs are more than met with the ounce per hour.

by on Oct. 24, 2012 at 10:34 AM
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The rule is based on the average amount of milk that a baby will need per 24 hours. (between 19-30oz) It's not a hard/fast rule, but it's a rule that IF POSSIBLE allows mom to maintain a healthy supply while not needing to supplement.

it's actually a 1-1.25oz/hour rule, and there are other components to it such as "bottles no larger than 3oz at a time".

Since mom's milk production varies significantly across the day, and since what mom pumps is different from what baby gets directly from the breast I can think of a number of situations that would cause the one ounce per hour rule to not work too well.

I am wondering at what age you found the rule to be bad for you, though. Because breastfed babies go through multiple growth spurts where that behavior is normal (waking frequently at night). If you experienced that behavior during a growth spurt it was normal.

How much milk does your baby eat when fed on demand? (ounces per hour)? And in what size bottles? I'm just curious.

by Silver Member on Oct. 24, 2012 at 10:35 AM
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She was reverse cycling when with you. The point is for her to see mom as her main milk source and not the bottle. Did you limit her night feedings? That may be why she lost weight.
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by Gold Member on Oct. 24, 2012 at 10:35 AM
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BTW, sleeping through the night really shouldn't be a goal. The 1 ounce per hour rule is to keep baby from developing a flow preference. She was behaving exactly as she should. BTW, waking at night often happens for lots of other reasons and is a safety mechanism against sids. You know that 5 hours is medically considered "through the night," correct?

by on Oct. 24, 2012 at 10:35 AM
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It's some ridiculous rule on kellymom that you should only feed your baby 1-1.25 oz of pumped milk an hr when you're not home to bf. It may work if you're going out for a few hours, or even if you work part time, but it's a terrible rule to follow if you work full time. I researched it more and there's no science behind it. There's also no lactation consultant that will endorse it.

Quoting MamaToCollin:

I don't think I've heard this one before, what's the 1 oz an hour rule?

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by on Oct. 24, 2012 at 10:37 AM

Never heard this before. 

by on Oct. 24, 2012 at 10:38 AM
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We also tried the ounce per hour rule, but it only lasted about a day. Baby boy was NOT NOT NOT happy with only three ounces every three hours. We went to four ounces every three hours and he was much better. (which I realize is only .25 ounces more than the 1.25 ounce per hour, but does go against the only offering a  3 ounce bottle.

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