Body Mass Index in babies

A baby's BMI is something that concerns us from the very first moments of their life. And it is so important that we've decided to bring together a few key points about it. So — how to calculate it, what it is for, and how to choose baby's clothing based on BMI: these are all the questions we'll attempt to answer in this article.

What is BMI and how do you calculate it?

BMI is a correlation between weight and height. What we call BMI stands for Body Mass Index. It assesses a person's build in order to identify potential health risks. Moreover, it is the only index validated by the World Health Organisation. It is a universal formula that involves dividing weight by height squared. So: BMI = Weight / Height x Height (in metres).

What is BMI used for with babies?

Using this figure, we essentially categorise the individual. This is how we determine whether a person is underweight, of normal build, overweight or indeed obese. Obesity can be moderate, severe or morbid. But in truth, for a child — and especially a baby — things work slightly differently. Indeed, once calculated, the result is plotted on the growth curve in their health record. It is from this that the type is identified against the norm, in order to prevent overweight and obesity. It is worth keeping in mind that baby's sex is taken into account in this calculation. A small tip: at every check-up, make sure the practitioner records it properly in the health booklet!

Tracking baby's development

If you would like to closely monitor your little one's development, there are centres known as maternal and child health centres (PMI — Protection Maternelle et Infantile). These are a regional service responsible for safeguarding the health of both mother and child. These places, specially adapted for monitoring mums and babies, allow you to, among other things, check baby's growth curve. So don't hesitate to ask about weight-monitoring sessions at your local PMI. This can also help you when choosing clothing to buy.

Buying baby clothes based on their BMI

It is important that we alert you about choosing the right sizes based on BMI. That is to say, just because baby is 6 months old does not mean you should buy 6-month-sized clothing. Of course not. Just as when buying shoes: if their foot measures a size 4, that doesn't mean their foot is actually that many centimetres long!

Indeed, we tend to go by height in centimetres instead. Sometimes you may even buy a 3-month bodysuit whilst the sleepsuit needed is 6 months. What matters most in all of this is that baby is comfortable in everything you put on them. The only way to know is to check. Simply take the time to see. Nappy-changing time is a moment of closeness. Even if baby tends to wriggle a great deal, do take the time to try everything on them.

And one last little tip before we go — think about the season before stocking up on clothes in advance! On the other hand, you can always embrace a minimalist approach to life.