Australasian Science: Australia's authority on science since 1938

Why Size Matters at Birth

Credit: Dmitry Lobanov/Adobe

Credit: Dmitry Lobanov/Adobe

By Marie-Jo Brion

A large genetic study has determined why small babies are at greater risk of disease as adults.

The full text of this article can be purchased from Informit.

There’s a longstanding interest in birthweight, with documented examples of its routine assessment in European hospitals as far back as the 1850s. Today, birthweight is an established indicator of an infant’s health at birth, but it also relates to a baby’s chances of survival and health later in life. As such, measurement of birthweight is almost universally a part of all modern newborn health assessments.

Birthweights vary widely, spanning from 2500–4500 grams within the normal range. Around one in 16 Australians are born in the low birthweight category of less than 2500 grams.

Birthweight is a blunt measure of the overall growth and development of a foetus in the womb. It reflects the accumulation of many biological processes, some of which are known but many of which have simply not yet been identified.

Pre-term births, as well as multiple births, are associated with low birthweight because an early birth or a shared womb limits the extent to which a baby can grow in utero. However, the causes of low birthweight for a full-term infant are not entirely clear.

Parental size, as well as maternal health and behaviour during pregnancy, play a role. In particular, smoking during pregnancy and poor prenatal nutrition can adversely affect the developing foetus and reduce its size at birth. These factors are also linked to lower socioeconomic...

The full text of this article can be purchased from Informit.