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Breaking Down Growth Spurts

Provider measuring growth of an infant.

Someone recently challenged my use of the term “growth spurt.” The question was, “Marie, is there any evidence to support the concept of “growth spurts”?

It did give me pause.

Using the phrase “growth spurt” I searched PubMed and filtered results to pull up only studies in the birth to 23 months group. I found 10 studies, none of which substantiated the definition of a “growth spurt.”

I did find one article (not a study) written by Karlberg in 1990 that addressed growth spurts. The abstract said:

Early normal human linear growth is unstable and oscillates owing to an increase in growth rate between 6 and 12 months of age. This defines the onset of the infancy-childhood growth spurt (IC spurt).

Hence, I suppose one could argue that the term “growth spurt” is not evidence-based. But from a more practical, clinical standpoint I can tell you, with certainty, that infants do have periods of increased caloric needs and resulting growth during that first year after birth.

So, what’s easier to say? “Growth spurt” or “periods of increased caloric needs and resulting growth in weight and length?”

Like most parents — and most professionals — I call this a “growth spurt.”

Maybe you don’t care what to call it. You just want some answers to a few basic questions.

What is an infant growth spurt? 

When a baby has increased caloric needs here’s what you’re likely to see:

  • Increased frequency of hunger cues; hunger signals occur every hour or so.
  • Increased impatience at eating time. The baby seems ravenously hungry. Not just “regular” hungry, but frantic-hungry.
  • Alterations in sleep patterns: Sleeping more or sleeping during hours that are usually waking hours. Or, sleeping less and waking during times that are usually sleeping hours.
  • Increases in body weight
  • Having clothing that suddenly looks a little too snug.

When do growth spurts happen?

Well, babies don’t read calendars. So, it’s tough to say. And, if you read 10 different articles, you’ll probably find 10 different answers. Most would agree that these episodes usually occur at:

  • 10 days
  • 3 weeks
  • 3 months
  • 6 months
  • 9 months

What’s that? You hadn’t heard of the “10 days” growth spurt? Okay, well, it doesn’t get talked about much, but I’ve seen it happen many times.

How long do growth spurts last?

I’d say, count on 72 hours. Be happy if it passes sooner than that.

Meanwhile, that’s when I get all the calls from breastfeeding mothers who say, “I don’t have enough milk.” Well, for today, that’s probably true!

If you feel like you’re providing a 24-hour a day smorgasbord, your baby is probably having a growth spurt.

How can you tell if baby is getting enough milk?

At first, the baby probably isn’t getting enough milk. He’s getting enough milk to survive, but not to thrive.

Thankfully, your body knows how to make more milk. As I explained earlier, milk is regulated by a positive feedback loop.

Feel reassured by seeing many wet diapers in a day, and generally alert behavior.

How much do babies grow?

What about infant weight gain?  

Here’s a formula I learned more than 40 years ago. It’s not exact, but it’s a quick and easy way to help you know that growth is on track. In the first year, a healthy baby who was born at term will:

  • double in weight by 6 months
  • triple in weight by 1 year
  • quadruple in weight by 3 years

Similarly, linear growth has a clear pattern. Length will increase about:

  • ½ to 1 inch (1.5 to 2.5 cm) per month during the first 6 months
  • 3/8 inch (1 cm) a month during the last 6 months of the first year

In general, babies will gain 50% in length by the end of the first year.

We all know that babies grow. And hence, they all have “growth spurts” that are observable, and transient.

What indicators do you look for during growth spurts? When have you seen them happen? Share your experiences in the comments!

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    • Marie Biancuzzo

      Oh Jenya, I’m glad it was clear. I certainly thought I “knew” but I did a few re-writes in order to explain it! Thank you for such positive feedback.

  1. Jean Bonnyman, IBCLC

    Thank you. This was helpful. I cared for a Turkish family who are recent immigrants. They did not have a word for or even a concept of growth spurts, which I find so interesting.

    Also, I hear moms talk about “leaps.” Are they talking about growth spurts?

    • Marie Biancuzzo

      Yikes, Jean, I don’t know! I presume that means the same thing. My guess is that somebody is going around saying “there’s no such thing as a growth spurt” (which is why I wrote the post) and as a result, someone made up the term “leaps.” That would be my guess. I’m fairly persnickety about terms, and what they mean in a professional context, But in talking to parents, we need to be practical. To me, “growth spurt” works just fine. Which is why in the post I wrote: So, what’s easier to say? “Growth spurt” or “periods of increased caloric needs and resulting growth in weight and length?” Thank you for your comment.

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