Growth, size of babies worldwide remarkably similar

Ana Langer, director of the Women and Health Initiative and Maternal Health Task Force (MHTF) at Harvard School of Public Health, says that new findings from an international study on fetal growth and birth length debunk longstanding beliefs that variations among fetal and infant sizes have something to do with genetics, race, or ethnicity.

The consortium that produced this study — the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) — calls the new findings “landmark” on its website. Why is it so important to show that babies everywhere are born at roughly the same size?

Until now there has been no body of evidence that provided an answer to the question of whether fetal and infant growth was determined by maternal health and nutrition, genetics, race, or ethnicity. With this new study, the idea that some ethnicities and races may be genetically pre-determined to be smaller than others — which may have originated from current disparities in growth and size between and within countries — has been shown to be unfounded and untrue. Instead, the study found that fetal growth and birth length are incredibly similar around the world when babies are born to well-nourished, well-educated mothers. The new findings have, in short, provided us with a globally relevant understanding of what “normal” fetal and newborn growth is.