Motherhood

What’s the Average Newborn Weight?

Team Peanut
Team Peanutabout 2 months ago4 min read

Just how heavy is a new baby? We check out the average newborn weight and what affects it. And we explain why there’s no such thing as “normal.”

Average Newborn Weight

As a new mama, some questions are guaranteed to come your way.

Just behind “boy or girl?” might be “how much did they weigh?”

So what is the average newborn weight?











That’s what we’re here to find out!

We’re going to look at birth weight and what affects it.

And we’ll investigate whether there’s such a thing as normal (spoiler: there isn’t!).

In this article: 📝

  • Average weight of a newborn: the figures
  • What affects average newborn weight?
  • Is 6 pounds 14 ounces a small baby?
  • Is a 9 pound baby big?
  • Average newborn weight: The bottom line

Average weight of a newborn: the figures

So what is the average weight of a newborn?

A 2020 study found it was about 7 pounds 2.5 ounces.

That figure had decreased since 1990.

And it varies by sex. Boys tend to be slightly bigger.

Data from 2010 showed newborn boys weighed an average of 7 pounds 6 ounces.

The same year saw the average newborn girl weigh in at just under 7 pounds 4 ounces.

What affects average newborn weight?

Other factors, besides sex, also affect birth weight.

Genetics

Your baby inherits their physical characteristics from their parents.

So if you’re both tall with a bigger build, the chances are, your little peanut will be too.

That means they may be heavier at birth.

And if you’re both smaller in stature, it won’t be surprising if your baby follows suit.

Is your baby a twin — or even a quintuplet?!

If they were sharing your uterus, they’re likely to be born smaller than single babies.

There’s only so much room in there, after all!

With multiple births, babies are also often born early.

That, too, usually means a lower birth weight.

Length of the pregnancy

Babies that are born preterm — before the 37th week of pregnancy — will be smaller.

That’s because if they hadn’t arrived early, they’d still have been growing inside your uterus if they hadn’t arrived early.

Birth order

If this is your first baby, they’ll often be smaller than siblings that follow later.

A 2020 study found that birth weight increased with birth order.

Your health

Some health conditions can affect your baby’s growth in the uterus.

If you have diabetes, your baby may be larger than average.

If you have high blood pressure or problems with your heart, they may be smaller.

Your diet and weight

Putting on weight while you’re pregnant often means a bigger baby.

You might think that’s logical — carrying a larger baby means you’ll be heavier yourself.

But the relationship works the other way around too.

A study in 2000 found that gaining 35 pounds or more during pregnancy led to higher birth weights.

On the other end of the spectrum, being undernourished leads to smaller babies.

Your baby’s health

Just as your health can affect birth weight, so can your baby’s.

Some medical conditions can affect their growth and result in lower birth weight.

Is 6 pounds 14 ounces a small baby?

The question of what counts as a small or big baby is tricky.

We can talk about average weights — but that disguises a big range.

Most babies born full term weigh between about 6 and 9 pounds.

6 pounds 14 ounces is towards the lower end of that range.

But that doesn’t make a baby of that weight officially “small.”

Is a 9 pound baby big?

The same goes for what counts as “big.”

A baby weighing 9 pounds is above the average newborn weight.

But they’re still in the same range as lots of their peers.

And as we’ve seen, many different factors influence newborn baby weight.

So what’s a normal weight for one baby can be quite different for another.

Average newborn weight: The bottom line

While lots of us love talking about baby weight, there’s really no such thing as normal here.

The average newborn weight encompasses a big range of perfectly healthy-sized babies.

If your baby’s weight falls outside that 6 to 9-pound range, the doctors will probably just want to keep an eye on things so they can take action if it’s needed.

And if you need support along the way, reach out to your Peanut community.

We don’t have to do this alone. ❤️

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