Breastfeeding, Weight Gain and Growth Charts

A baby’s weight can be a big source of stress for breastfeeding mothers. Is my baby gaining too little or too much? Are they on the right percentile? Am I making enough milk? Often, these concerns stem from parents, and even health care providers, not having a good understanding of what is normal when it comes to babies and weight.

So what is normal? Well, to start with, it is normal for babies to lose some weight after birth. Peak weight loss usually happens on day three (just before mom’s milk “comes in”). Weight loss in hospital is often a big concern, and unfortunately, often a reason for breastfed babies being unnecessarily supplemented with formula. Most hospitals use the measurement of 7% loss from birth weight as an indicator of a problem. The latest research however is giving us new insight into normal newborn weight loss. Dr. Joy Noel-Weiss recently completed a research study looking at newborn weight loss and how that weight loss is affected by IV fluids given to mom during labour. Her findings confirmed what many in the lactation community have thought for some time. IV fluids can artificially inflate a baby’s birth weight. Her study found that IV fluids given to mom during labour and delivery, particularly in the two hours immediately prior to birth, have an impact on how much weight a baby loses after birth. All of that extra fluid has to go somewhere, and some of it goes to baby. After a baby is born and gets rid of the extra fluid, it can look like that baby has lost too much weight. One of the recommendations of the study is that all babies be weighed at 24hrs to allow babies to get rid of any extra fluids they may have in their system, and to use the 24hr weight to calculate weight loss/gain rather than birth weight.

In terms, of weight gain, a healthy term newborn should regain their birth weight by about 7-10 days. A healthy newborn baby who is transferring milk well, is a baby who is growing and gaining weight (after about day 3). If your baby isn’t gaining, or is gaining very slowly, it’s a red flag that something isn’t quite right and breastfeeding needs to be assessed. The first course of action should always be to figure out what is causing the slow weight gain. Whether it’s an issue with mom’s milk production or a problem with baby’s ability to transfer milk effectively, the cause of the problem needs to be determined by someone knowledgeable about breastfeeding. In the first few days in hospital, if your baby is not nursing well and weight gain is a concern, then constant skin-to-skin contact and frequent hand expression and spoon feeding of colostrum are the best approach. If you are being pressured to give formula, you can ask for more time and then get help from an IBCLC.

Once breastfeeding is established, we expect babies to gain at a rate of about 5-7 oz per week (close to an ounce per day), for about the first 3 months. Between months 3-12, weight gain tends to slow down. It is normal for the rate of weight gain to slow down, but it is not normal for weight gain to stop completely or for babies to lose weight. The average breastfed baby doubles their birth weight by about 5-6 months, and at 1 year, they typically weigh 2.5 times their birth weight.

The Centers for Disease Control and Prevention (CDC) and the Canadian Pediatric Society (CPS) both recommend that children’s growth be plotted on the new World Health Organization (WHO) growth charts. The WHO charts, unlike the old CDC charts, are based on the growth of babies under biologically normal conditions (breastfeeding, mothers who don’t smoke etc). When looking at a child’s growth, it is important to be comparing their growth with the biological norm.

For many parents (and health care providers!) growth charts can be a source of great confusion and misunderstanding. When you visit your child’s doctor, their weight is usually plotted on a weight for age growth chart. These charts are used to compare your child to others of the same gender and age. If (for example) your baby’s weight falls on the 25th percentile, it means that statistically speaking, 25% of all babies are that weight or below. Or, to look at it the other way, that 75% of all babies are above that weight. It is very important to understand that the percentile itself is NOT an indicator of health. A baby on the 97th percentile is not healthier than a baby on the 3rd percentile, they just weigh more. Someone has to fall in the 97th percentile, and someone has to fall in the third. What is important is whether or not your child is following their own curve. It is also very important to understand that the 50th percentile does not equal normal or healthiest weight.  The 50th percentile simply means that 50% of all babies are that weight or below. Parents should never be instructed to supplement with formula simply because their breastfed baby is following the 3rd percentile or reduce feedings because their baby is on the 97th percentile. That is NOT how growth charts are meant to be used.

Growth charts are screening tools, not diagnostic tools. This means that if a child is not following the expected pattern according to where they are on the chart, then the doctor needs to look closer to see if something else might be going on. It does not automatically mean that there is a problem.  If a doctor has concerns about a child’s growth then that doctor needs to be looking closely at all aspects of that child’s growth and development. There are several different types of charts available from the World Health Organization, and the weight for length charts or BMI for age charts provide a more accurate picture of an individual child’s growth than the the weight for age ones do.

Weight is only one indicator of growth and should never be looked at in isolation. It is necessary to look at the big picture. The most important thing for parents (and health care providers) to remember is  look at your baby, not just the scale. If your baby is alert and happy, content after feeding, pooping, peeing, meeting developmental milestones, feeling heavier, and outgrowing clothes and diapers, then everything is good (look how many other factors besides weight can tell you that your baby is thriving on your milk!).


  1. Athenkosi Allen says:

    hello my daughter is 3months old and she weighs 8kg,is it normal im a bit worried about her weight that maybe I’m breastfeeding her too much.Exclusive breastfeeding.

    • Morning Athenkosi

      My baby was weighing 9kg at our 15 weeks checkupand they said he was overweight, he is 5 months today but still look big…. im hoping he will shed some of the weight when he starts crawling. what’s your situation now?

  2. Hi my baby is 12weeks so I’m worried she gain her weight well

  3. My daughter is 12 months 3 weeks, she weighs 16,5 kgs, started walking, must I be concerned?

  4. Kathrine de guzman says:

    Hello everyone i give birth to my youngest may 31 2016,,she weight 2,8kl,and now she is 1 month and 25 days old,,she weight 5,4kl now,,is this a normal weight?what is the average weight of a 1 month and 25 days old almost 2 months.can someone answer my question.thank you 🙂

  5. 11 days old boy baby not passing stools but he is having milk every two hours but his voice is also very low when he crys

  6. Tanimomo Fisayo says:


    my baby girl is 7 1/2 month old and she weighs 6. Though i did exclusive breastfeeding and she also went through surgery at 2 months. Her birth weight was 4kg

    Now, she does like bottle fed but spoony. The amazing thing now she only eat with force.

    Please help.

  7. My son is 5 months old now, he was 8lbs 12 oz at birth and lost 10% after birth was 8lbs when I was sent home with him. He took 3 weeks to get back up birth weight and is currently only 13 lbs 3oz. He was born with a heart murmur, has severe reflux, and severe case if Laryngomalacia which he had surgical intervention at 3 months to help him breathe. Now he’s recovered from his surgery and not gaining weight still and is now being referred to ,”ready set grow” a clinic that deals with failure to thrive children. I’m just trying to get him all the help he needs

  8. Tina Hein says:

    I was needing some advice from some experts on breastfed babies. I have a son who was born on 12-23-2014 and was 7 pounds and 1 ounce. Now he is 4 months old and is falling off the charts for his weight. He is 12 pounds and 3 ounces. He went from 15% to now like 2%. He is very healthy-not been sick at all, strong and active. He is eating fine I told the doctor he is fed like every 2-3 hours in the day and at night I feed him once. He sleeps fine at night. He is a happy and mostly content baby. He does get fussy but we think he is starting to teeth. Oh and he has good output for urine and stools no problems there. I went through this with my older daughter who is going to be 8 years old. The doctors just gave me a hard time because of her weight and she is fine now.

  9. what is the awerage weight of a fourth month baby tell me in kg….

  10. Saritha Mary says:

    My son was born on March 12, 2013 & his birth weight was 3.07kg. Now he is in 4th month & carrying a weight of 7.5kg. Exclusively he is under breastfedding. I was worried that he is fat & one of the Doctor said that he is little fat due to genetic. But as far as my knowledge there is none of them from my side or my husband’s relatives are fat… Can any one clarify my doubt whether my son’s weight is normal or what can i do to keep him in normal weight.

    Thanks in advance…

  11. It is helpful to know that normally babies reach twice their birth weight by 5-6 months. My son has always been small and ‘slow’ to gain weight, gaining only around 100g a week, if that. I was made to worry, but I refused and went with my instinct. At five months, he is now about 4.6kg, so looks on track to reach twice his 2.5kg birth weight by 6 months. He is ‘small’ compared to every other baby I have seen! He is also constantly moving, kicking, chattering and absorbing every moment of his life.

    • Hi I know it is a really old post but I was wondering how your son has being since, as I am experiencing the same problem. My daughter is only gaining 100g a week. At 8weeks she is 3460g from 2800g… Is your son still petit?

      • Hi,
        I am shocked how everybody worries about child weights.myself too. Just spoke to my mum and she said that my middle sister was really far baby. She was breastfeeding every 3 hours and supplementing with formula ( cause thats what her doctor advised 25 years ago!) And my wee fat sister is 176 cm just now and look like anorexic. Eats normally and never tried to loose weight in her life. So I would not worry 😉 I am breastfeeding on demand and my 5 mo this old is 8.40kg (18lbs) and she was born normal weight 3.45kg (7 lbs 10). No solids yet bit will start soon 😉

    • Wow that sounds like what my baby is like now at 4 months he’s only 4.200 and pediatrician wants him to go to gastro. How is ur one now 3 years later?

    • How is your bubs doing now? My Bub is 4mo and 4kg

  12. Shelley Schwamberger says:

    So comforting and wish I could have read this 8 months ago when I was beside myself crying because lactation said our daughter was losing too much, almost 1.5 pounds, and want back to her birth weight by 2 Weeks! I was given so many fluids during labor with an epidural and she looked bloated when she was born and reading this makes sense that she was probably “water logged”! She is a happy, healthy 8 month old little girl and a pure joy and blessing! I would love to print this off and send it to our hospital lactation staff to prevent them from freaking other moms like me out! Thanks again for this article!

  13. It took my last baby 17 days to regain his “inflated” birthweight, but 14 days to go from his 3-day low of 8 pounds even to 8 pounds 12 ounces…. which is plenty in that time.

  14. Caroline says:

    I take issue with the blanket assertion that baby must have gained back all weight lost at birth by 2 weeks. Dr. Sears has noted in The Baby Book, for example, that small babies of small parents tend to put on weight more slowly and it is not unusual for them not to be back at their birthweight by two weeks. The same goes for the long, thin “banana” newborns. These are important exceptions. Supplementing indiscriminately because a baby has not met the 2-week birthweight target is a bad rule.

  15. Love this! “Look at your baby, not just the scale”- my husband and I are both small people but our daughter was born with weight and height in the 95 % . When she dropped to the 25% by her one year appointment, her nurse practioner wanted to run many types of tests. She made me feel terrible about my daughter’s health, suggesting things like cystic fibrosis, hyperthyroidism, and dwarfism. My daughter is a happy, healthy, active little girl who eats well and still breastfeeds. She has only had one cold in her short life and her size in clothes has always lined up with her age as well. I switched healthcare providers and was reassured she was in good health and her weight was fine.

  16. Stacey Donelson says:

    Thank you, thank you, thank you! This so clearly and explicitly explains the growth chart and how to appropriatly use them. My 2nd born was 6 lbs 6 oz at birth and even though she was growing, gaining weight and meeting all of her milestones either on time or early and is a very happy, healthy baby I still worried that she wasn’t getting enough milk because she consistently charts in the 25th percentile. It was so confusing because I knew she was doing ok…just couldn’t figure out how to get her into the 50%…its nice to know that my original feeling was correct. She’s perfectly fine.


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