Skip to content

Expert advice for local mamas: How fast should your baby grow?

West End Mamas founder, Sarah Mickeler, today kicks off a regular column at NewmarketToday
Sarah Mickeler, founder of West End Mamas. Greg King for NewmarketToday

Welcome to the first instalment in a regular column by Sarah Mickeler, founder of West End Mamas, a prenatal and postnatal clinic serving clients at two locations in Newmarket and Toronto.

Today, Mickeler breaks down how much you can expect your baby to grow, month by month.


Healthy babies differ in size and shape just as much as adults do and a baby’s growth will vary depending on multiple factors. 

While this is true, their growth will still usually follow a predictable path within the first year of their lives. 

Newborns (0-3 months) 
It is extremely common that immediately after birth, newborns can lose anywhere between 5 per cent and 10 per cent of their birth weight. 

Babies are born with extra fluid in their systems, so it’s expected for them to drop a few ounces when they start to lose that fluid. 

This is a completely normal process and healthy babies should start to gain back that weight within two weeks or so of being born. 

It shouldn’t take long for them to be right back at their birth weight, but if you are concerned that they haven’t, speak to your health-care professional.

In fact, newborns will grow faster in the first couple of months than at any other point in their lives. 

This has a lot to do with the kind of food they are eating, among other considerations. 

Babies who are exclusively breastfed will grow faster in the first two months than babies who are fed using formula. 

Breast milk provides optimal nutrition for infants as it has a near-perfect blend of proteins, vitamins and fat your baby needs to grow. 

However, breastfed infants will grow at a slower pace than those who are formula-fed after the first few months. 

Breastmilk changes to respond to your baby’s nutritional needs as they grow and develop, whereas formula remains relatively the same. 

Ultimately, there is no right or wrong answer when it comes to breast milk versus formula, it all comes down to what’s right for each and every mama and their little one.

Once your baby’s growth and weight have stabilized, their expected growth trajectory should be relatively easy to track. 

Each month after the first, your baby should gain about 1.5 to 2 pounds and grow 1 inch to 1.5 inches. 

Closer to the end of the newborn phase, your baby might start to look a little chubby, however, as their activity level increases, their little rolls will soon give way to developing muscle. 

It is rare that a baby is too big. The only real reason for concern would be if your baby has grown too large as an outcome of you having gestational diabetes, which is diagnosable during pregnancy through blood tests and ultrasounds. 

Gestational diabetes simply means your baby received higher amounts of sugar than normal while in the womb. It is manageable with a proper diet and medication to regulate insulin production, if necessary.

Infants (4-8 months) 
After three months, babies’ weight gain starts to slow down to 4 to 5 ounces per week on average. 

However, these averages can be misleading. A baby’s growth is tracked in a growth chart that shows the pattern of anticipated growth for healthy babies using centiles. 

For example, if your baby is marked on the 25th percentile at birth, they will be bigger than approximately 25 per cent of babies and smaller than 75 per cent. 

While these centile measurements can be helpful, a better way to judge your baby’s growth is using their growth curve. 

It doesn’t really matter what centile they are in, so long as they are growing at the expected rate in a healthy manner. 

When using these charts, it is just as important to look at height as well as weight, and how they correlate. 

If your baby has gained a lot of weight, but they’ve also grown significantly, then it’s OK. Whereas, if your baby’s weight gain does not match an increase in height, they could be slightly overweight, which is something your doctor can help you manage.

By 4 to 6 months, your baby should be double their birth weight. Within the first 6 months, their head’s circumference will increase by roughly 8 cm to 9 cm. 

At the infancy stage of your child’s life, they will require more calories in relation to size than a preschooler or school-aged child. This is to help them build muscle, gain weight and have more energy.

Toddler (9 months and up) 
It is common for babies to have a growth spurt around 9 months of age, and also have a corresponding sleep regression, unfortunately. 

We’re not going to quote average baby weights here because, truly, the most important thing is your own baby’s curve.  

If you have any concerns about your baby’s growth at this time, by all means, contact your pediatrician.  

By 12 months, your baby may have tripled their birth weight. Again, some babies will grow bigger than others, so don’t be alarmed if your baby hasn’t.  

Babies, just like adults, come in all shapes and sizes. Your baby will likely also have grown roughly 9 inches to 11 inches from their birth height. 

After their first year, a baby’s growth will decrease in speed. On average, your kiddo will gain 3 pounds to 5 pounds and 3 inches to 5 inches every year after 12 months. 

By 24 months, most baby’s birth weight may have quadrupled and they may have grown 14 inches to 16 inches from their birth length.

The National Center for Chronic Disease Prevention and Health Promotion (CDC) has a complete baby-growth chart guide that is grouped by age, height, weight and percentile for 0- to 36-month-olds. 

While we have discussed how babies will follow a growth curve, it’s important to know and keep in mind that healthy babies can go through brief periods when they stop gaining or even lose weight. It is likely nothing to be concerned about. 

Your doctor will only worry if there hasn’t been any weight gain from one well-baby exam to the next. At each of these visits, your baby’s weight, height and head circumference will be tracked on their growth chart.

Just remember, every baby is different and no two babies will develop in the same way. 

That being said, if you’re ever at all concerned, make an appointment with your pediatrician and they can point you in the right direction for the care your baby needs.

West End Mamas was established in 2017, and is the GTA’s original and premier prenatal and postnatal clinic with two locations serving Toronto and York Region. A dedicated wellness clinic for mothers and mothers-to-be, West End Mamas provides a wide range of services including acupuncture, chiropractic care, pelvic floor physiotherapy, osteopathy, psychotherapy and counseling, nutrition, doula services, lactation support, postpartum support, plus engaging workshops, a caring community, and more. For more information, visit here.