Scales and growth charts – Making sense of them

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How much did the baby weigh? That is one of the first things people will ask once your baby has arrived. They may comment, upon hearing the answer, “that’s big!” or perhaps, “oh, so tiny!” I almost never hear, “sounds like the perfect weight.”

As your baby grows, weight can be a source of pride, almost like it’s equivalent to IQ. It can also be a source of stress, especially if your baby is not gaining enough, or is a slow grower.

I have a scale at the breastfeeding group that I facilitate and the moms use it every time they come. Every single time. Some moms will come, just to weigh their baby. Some of those babies are huge! Still, moms want to know how much they weigh They want that reassurance that he is gaining.

Issues around weight are one of the most common questions I get at that group. Is he gaining enough? Is he gaining too much? He didn’t gain as much this week as he did last week, should I supplement him with formula? The doctor says he’s not gaining enough, and I need to supplement him with formula, but I don’t want to do that, what are my alternatives? The weight questions are endless.

There are many things you should know about weight that should reassure you. Remember though, always look at your baby first. Is he reaching his developmental milestones? Is he alert and interactive? Does he have roll upon roll, and three double chins? What are his other measurements, especially head circumference?

When it comes to weight, there seem to be two things that can make a mom beam with pride, or strike fear in her heart. The baby scale, and the growth curve chart.


Photo credit: bikesandwich via / CC BY-NC-SA

Let’s first go back to the beginning. When a baby is born it is weighed, and that weight is plotted on a graph that determines if it is an average weight for its gestation, larger than average or smaller than average. Gestation is the number of weeks you were pregnant. In the first 2-3 days, your baby will usually lose some weight. A loss of up to 10% of his body weight is considered normal. A baby that loses too much weight may be supplemented. After your milk comes in, your baby should start gaining weight. If you have a sufficient amount of milk, and if he is feeding well, then he should be back to his birth weight at no later than two weeks of age. It is expected that he will be gaining steadily during that time and then will continue to gain ¾ to 1 oz. a day, or 5-7 oz. every week. This is going to be a little less than 1 pound every 2 weeks. The weight gain should continue at this rate until he is 3-4 months old, at which time that weight gain will have slowed to a rate of 3-5 oz. per week, which is roughly a pound a month. The rate of gain slows down even more after 6 months. If your baby is gaining an average amount of weight, he will probably have doubled his birth weight by 5-6 months and tripled it by a year.

In the first couple of months, it is expected that your baby will grow at a consistent weight. The vast majority of the time a baby is not growing enough is because they are not getting enough to eat, for one reason or another. By about 3 months a lot of babies will not grow as consistently. I believe this didn’t use to be as much of an issue because babies weren’t weighed as frequently, and we just didn’t know. Moms weren’t weighing their baby every week. Your baby may not gain as much or even gain anything at all one week, and then he will make up for it a week or two later.

To review expected weight gain:

  • Up to 10% weight loss normal in the first few days
  • Should start gaining weight back when milk comes in
  • Back to birth weight by 2 weeks
  • Gain 3/4 – 1 oz./day for 1st 3-4 months = 3-5 oz./week
  • Gain 1/2 oz./day months 4-6 = 3-5 oz./week
  • Gain 1-2 oz. week months 6-12
  • Double birth weight by 5-6 months
  • Triple birth weight by 1 year

Growth Charts

Breastfed babies grow in a pattern similar to formula fed babies for the first 3 months and then usually grow at a slower rate for the rest of the first year. That is the reason I tell moms who have very chubby babies and are worried that their baby may be gaining too much weight, that it is not a concern. They usually will slim down once they start crawling and walking.

When you take your baby to the pediatrician they will weigh him, at least at his well-baby check-ups, and usually any time you come in for a visit. They will put this weight on a growth chart. Make sure they always weigh him naked, and it will be most accurate if it is right before he eats, or midway between the last and the next feeding. Weighing a baby with clothes or a diaper, as well as weighing right after a feeding, will give a weight that is higher than is his true weight. When we are looking at how many ounces he has gained in a week or two, 3 oz. makes a difference.

What is a growth chart? How did they come up with what is used today?

“The WHO growth charts are international standards that show how healthy children should grow. The standards describe the growth of children living in six countries (including the United States) in environments believed to support optimal growth. One of the several criteria defined for optimal growth is breastfeeding. The WHO growth charts use the growth of breastfed infants as the norm for growth. This is in agreement with national guidelines that recommend breastfeeding as the optimal infant feeding method. The WHO growth charts should be used with all children up to aged 2 years, regardless of the type of feeding. • The CDC growth charts are a national reference that represents how US children and teens grew primarily during the 1970s, 1980s, and 1990s. The CDC recommends using the references from ages 2 through 19 years so health care providers can track weight, stature, and body mass index (BMI) from childhood through age 19 years.” (

Growth charts used to be based on the growth of formula-fed infants. Then for awhile, they were based on a combination of some breastfed infants and some formula fed. Now the charts that are used are usually based on breastfed infants because that is recognized as the normal way to feed a baby. There are different charts for boys and girls. There are a number of Apps that you can use if you want to have your growth chart.

Some of the moms I work with have shared with me that their baby’s pediatrician told them that in the first few months a gain of only ½ oz. per day is ok. This will result in a baby falling down in percentile on a growth chart. You can see from the picture below that would result in a baby going from being born at the 50th percentile to being below the 3rd percentile by 3 months.

Percentiles and Curves

It is important to remember that it’s not really important where your baby is on a growth chart, but whether they are growing along their curve, even if it is below the 3rd percentile. Somebody has to be there, by definition of a statistical curve, which is what the growth charts are based on.

It seems that when a baby is at a high percentile on the growth chart, parents will brag about it. However, it just means their baby is larger than most other babies. It doesn’t mean they will be smarter, better looking, a better athlete or a nicer person. It only means they are larger than other babies their age. It’s kind of funny. When your child is older, and certainly this is certainly true for adults, nobody thinks it’s better to weigh than average.

Parents often will be worried if their baby is in the lower percentile on a growth chart. I am often asked how to get a baby to gain more to move them up on the growth curve. One mother came to my breastfeeding group and was worried because her baby had only been gaining ½ oz. a day on average. I just explained the problem with that. Her pediatrician had told her that this was fine, however, she started feeling like it wasn’t fine. Moms usually have good instincts. We talked about some ways to increase his intake, and it was primarily by breastfeeding him more often. This did result in a more average weight gain, and he did move to a higher percentile on the growth chart. She became fixated on getting him to the 50th percentile though and kept asking me how she could get him there. I looked at her one day and said, “You could force feed him, but I don’t recommend it.”

I also had a mom whose baby was a slow gainer. She didn’t worry about it at all. Her baby was healthy and progressing at a developmentally appropriate rate. She didn’t worry about the weight at all. She looked healthy, she was just small.

Growth charts are a reference, and a tool, that let your baby’s doctor know if your baby is growing at an average rate. Furthermore, they are only one type of measurement that is taken. Length and head circumference, and later on, BMI, will also be measured. Developmental milestones will also be assessed.

If your baby is a slow grower, step back and take a look at everything. Is everything else I just mentioned increasing appropriately? Is there an adequate amount of milk? Is that milk made available to your baby? Rigid schedules and sleep training are really not appropriate for a slow grower. Are you reading your babies cues for hunger properly? If you are concerned, talk to a lactation consultant.

One final thought

Large, average, or small, it’s your baby. He is your perfect baby. You are his perfect mom. If you are worried whether he is growing perfectly, there is help out there.

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