All Babies Should Ideally Be the Same Size

Newborns are quite literally not created equal, boasting very different sizes depending on how and when they were birthed. However, researchers are now claiming that despite ethnicity, the size of their mother, or how tall or large they will grow further down the line, all babies should be born the same.

That is, according to a study recently published in the journal The Lancet, which details how, given ideal conditions, a human fetus should not start experiencing a varied rate of growth until after birth.

To determine this, data was collected on thousands of health and happy newborns from the United States, United Kingdom, China, Brazil, Oman, Kenya and Italy, as part of the INTERGROWTH-21st Project. This data was then used to plot out standard growth charts for newborns, focusing on weight, length, and head circumference.

Interestingly, while there were some regional differences, they were found to be only slight as long as the birth was timely and the mother was of a healthy weight. Even more encouragingly, these average global sizes fit perfectly in with the World Health Organization's existing Child Growth Standards.

"The fact that when mothers are in good health, babies grow in the womb in very similar ways the world over is a tremendously positive message of hope for all women and their families," Zulfiqar Bhutta, the chair of the Steering Committee of the INTERGROWTH research team, said in a statement.

Research lead Stephen Kennedy adds that this "one size fits all" approach for assessing baby growth could make it significantly easier for doctors, no matter where they are in the world, to ensure a newborn's health. He claims that as things stand, without a standardized and globally recognized size, it is far too likely that intervention could be taken where none is needed, and vice-versa.

However, not everyone agrees. Jason Gardosi, director of the Perinatal Institute in Birmingham, UK, told New Scientist that by ignoring genetic influences, this new standard could confuse things further.

"It means that smallish ladies, or ladies of different ethnicities who are absolutely normal and healthy, could be told that their baby is pathologically small because of a one-size-fits-all standard."

However, Kennedy stands by his team's work, claiming that while a standardized measurement will never be perfect, it has been shown that genetics has a far smaller effect on growth than environment .

"Don't tell us nothing can be done. Don't say that women in some parts of the world have small children because they are predestined to do so. It's simply not true," added the study's lead author, Jose Villar. "We can create a similar start for all by making sure mothers are well educated and nourished, by treating infection and by providing adequate antenatal care."